Merge remote-tracking branch 'github-sgothel/master' into armv6hf

1 files changed, 1943 insertions, 0 deletions

diff --git a/src/jogl/classes/com/jogamp/opengl/FBObject.java b/src/jogl/classes/com/jogamp/opengl/FBObject.java
new file mode 100644
index 000000000..644d87b1a
--- /dev/null
+++ b/src/jogl/classes/com/jogamp/opengl/FBObject.java
@@ -0,0 +1,1943 @@
+/**
+ * Copyright 2012 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
+package com.jogamp.opengl;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+import javax.media.opengl.GL;
+import javax.media.opengl.GL2GL3;
+import javax.media.opengl.GL3;
+import javax.media.opengl.GLBase;
+import javax.media.opengl.GLContext;
+import javax.media.opengl.GLException;
+import javax.media.opengl.GLProfile;
+
+import jogamp.opengl.Debug;
+
+import com.jogamp.opengl.FBObject.Attachment.Type;
+
+/**
+ * Core utility class simplifying usage of framebuffer objects (FBO)
+ * with all {@link GLProfile}s. 
+ * <p>
+ * Supports on-the-fly reconfiguration of dimension and multisample buffers via {@link #reset(GL, int, int, int)}
+ * while preserving the {@link Attachment} references.
+ * </p>
+ * <p>
+ * Integrates default read/write framebuffers via {@link GLContext#getDefaultReadFramebuffer()} and {@link GLContext#getDefaultReadFramebuffer()},
+ * which is being hooked at {@link GL#glBindFramebuffer(int, int)} when the default (<code>zero</code>) framebuffer is selected.
+ * </p>
+ * 
+ * <p>FIXME: Implement support for {@link Type#DEPTH_TEXTURE}, {@link Type#STENCIL_TEXTURE} .</p>
+ */
+public class FBObject {
+    protected static final boolean DEBUG = Debug.debug("FBObject");
+    
+    /** 
+     * Returns <code>true</code> if basic FBO support is available, otherwise <code>false</code>.
+     * <p>
+     * Basic FBO is supported if the context is either GL-ES >= 2.0, GL >= core 3.0 or implements the extensions
+     * <code>ARB_ES2_compatibility</code>, <code>ARB_framebuffer_object</code>, <code>EXT_framebuffer_object</code> or <code>OES_framebuffer_object</code>.
+     * </p>
+     * <p>
+     * Basic FBO support may only include one color attachment and no multisampling,
+     * as well as limited internal formats for renderbuffer.
+     * </p>
+     * @see GLContext#hasFBO()
+     */
+    public static final boolean supportsBasicFBO(GL gl) {
+        return gl.getContext().hasFBO();
+    }
+  
+    /** 
+     * Returns <code>true</code> if full FBO support is available, otherwise <code>false</code>.
+     * <p>
+     * Full FBO is supported if the context is either GL >= core 3.0 or implements the extensions
+     * <code>ARB_framebuffer_object</code>, or all of
+     * <code>EXT_framebuffer_object</code>, <code>EXT_framebuffer_multisample</code>, 
+     * <code>EXT_framebuffer_blit</code>, <code>GL_EXT_packed_depth_stencil</code>.
+     * </p>
+     * <p>
+     * Full FBO support includes multiple color attachments and multisampling.
+     * </p>
+     */
+    public static final boolean supportsFullFBO(GL gl) {
+        return gl.isGL3() ||                                                         // GL >= 3.0
+                
+               gl.isExtensionAvailable(GLExtensions.ARB_framebuffer_object) ||       // ARB_framebuffer_object
+               
+               ( gl.isExtensionAvailable(GLExtensions.EXT_framebuffer_object) &&     // All EXT_framebuffer_object*
+                 gl.isExtensionAvailable(GLExtensions.EXT_framebuffer_multisample) &&
+                 gl.isExtensionAvailable(GLExtensions.EXT_framebuffer_blit) &&
+                 gl.isExtensionAvailable(GLExtensions.EXT_packed_depth_stencil) ) ;
+    }
+    
+    public static final int getMaxSamples(GL gl) {
+        if( supportsFullFBO(gl) ) {
+            int[] val = new int[] { 0 } ;
+            gl.glGetIntegerv(GL2GL3.GL_MAX_SAMPLES, val, 0);
+            return val[0];
+        } else {
+            return 0;
+        }
+    }
+    
+    /** Common super class of all attachments */
+    public static abstract class Attachment {
+        public enum Type { 
+            NONE, DEPTH, STENCIL, DEPTH_STENCIL, COLOR, COLOR_TEXTURE, DEPTH_TEXTURE, STENCIL_TEXTURE;
+            
+            /** 
+             * Returns {@link #COLOR}, {@link #DEPTH}, {@link #STENCIL} or {@link #DEPTH_STENCIL}
+             * @throws IllegalArgumentException if <code>format</code> cannot be handled. 
+             */
+            public static Type determine(int format) throws IllegalArgumentException {
+                switch(format) {
+                    case GL.GL_RGBA4:
+                    case GL.GL_RGB5_A1:
+                    case GL.GL_RGB565:
+                    case GL.GL_RGB8:
+                    case GL.GL_RGBA8:
+                        return Type.COLOR;
+                    case GL.GL_DEPTH_COMPONENT16:
+                    case GL.GL_DEPTH_COMPONENT24:
+                    case GL.GL_DEPTH_COMPONENT32:
+                        return Type.DEPTH;
+                    case GL.GL_STENCIL_INDEX1:
+                    case GL.GL_STENCIL_INDEX4:
+                    case GL.GL_STENCIL_INDEX8:
+                        return Type.STENCIL;
+                    case GL.GL_DEPTH24_STENCIL8:
+                        return Type.DEPTH_STENCIL;
+                    default:
+                        throw new IllegalArgumentException("format invalid: 0x"+Integer.toHexString(format));
+                }        
+            }
+        };
+                
+        /** immutable type [{@link #COLOR}, {@link #DEPTH}, {@link #STENCIL}, {@link #COLOR_TEXTURE}, {@link #DEPTH_TEXTURE}, {@link #STENCIL_TEXTURE} ] */
+        public final Type type;
+        
+        /** immutable the internal format */
+        public final int format;
+        
+        private int width, height;
+        
+        private int name;
+        
+        /** <code>true</code> if resource is initialized by {@link #initialize(GL)}, hence {@link #free(GL)} is allowed to free the GL resources. */
+        protected boolean resourceOwner;
+        
+        private int initCounter;
+        
+        protected Attachment(Type type, int iFormat, int width, int height, int name) {
+            this.type = type;
+            this.format = iFormat;
+            this.width = width;
+            this.height = height;
+            this.name = name;
+            this.resourceOwner = false;
+            this.initCounter = 0;
+        }
+        
+        /** width of attachment */
+        public final int getWidth() { return width; }
+        /** height of attachment */
+        public final int getHeight() { return height; }
+        /* pp */ final void setSize(int w, int h) { width = w; height = h; }
+        
+        /** buffer name [1..max], maybe a texture or renderbuffer name, depending on type. */
+        public final int getName() { return name; }        
+        /* pp */ final void setName(int n) { name = n; }
+        
+        public final int getInitCounter() { return initCounter; }
+        
+        /** 
+         * Initializes the attachment buffer and set it's parameter, if uninitialized, i.e. name is <code>zero</code>.
+         * <p>Implementation employs an initialization counter, hence it can be paired recursively with {@link #free(GL)}.</p>
+         * @throws GLException if buffer generation or setup fails. The just created buffer name will be deleted in this case. 
+         */
+        public void initialize(GL gl) throws GLException {
+            initCounter++;
+            /*
+            super.initialize(gl);
+            if(1 == getInitCounter() && 0 == getName()  ) {
+                do init ..
+                freeResources = true; // if all OK
+            }
+            */
+        }
+        
+        /** 
+         * Releases the attachment buffer if initialized, i.e. name is <code>zero</code>.
+         * <p>Implementation employs an initialization counter, hence it can be paired recursively with {@link #initialize(GL)}.</p>
+         * @throws GLException if buffer release fails. 
+         */
+        public void free(GL gl) throws GLException {
+            /*
+            if(1 == getInitCounter() && freeResources && .. ) {
+                do free ..
+            }
+            super.free(gl);
+            */
+            initCounter--;
+            if(0 == initCounter) {
+                resourceOwner = false;
+                name = 0;
+            }
+            if(DEBUG) {
+                System.err.println("Attachment.free: "+this);
+            }
+        }
+        
+        /**
+         * <p>
+         * Comparison by {@link #type}, {@link #format}, {@link #width}, {@link #height} and {@link #name}.
+         * </p>
+         * {@inheritDoc}
+         */
+        @Override
+        public boolean equals(Object o) {
+            if( this == o ) return true;
+            if( ! ( o instanceof Attachment ) ) return false;
+            final Attachment a = (Attachment)o;
+            return type == a.type &&
+                   format == a.format ||
+                   width == a.width   ||
+                   height== a.height  ||
+                   name == a.name     ;
+        }
+        
+        /**
+         * <p>
+         * Hashed by {@link #type}, {@link #format}, {@link #width}, {@link #height} and {@link #name}.
+         * </p>
+         * {@inheritDoc}
+         */
+        @Override
+        public int hashCode() {
+            // 31 * x == (x << 5) - x
+            int hash = 31 + type.ordinal();
+            hash = ((hash << 5) - hash) + format;
+            hash = ((hash << 5) - hash) + width;
+            hash = ((hash << 5) - hash) + height;
+            hash = ((hash << 5) - hash) + name;
+            return hash;
+        }
+        
+        int objectHashCode() { return super.hashCode(); }
+        
+        public String toString() {
+            return getClass().getSimpleName()+"[type "+type+", format 0x"+Integer.toHexString(format)+", "+width+"x"+height+
+                   ", name 0x"+Integer.toHexString(name)+", obj 0x"+Integer.toHexString(objectHashCode())+
+                   ", resOwner "+resourceOwner+", initCount "+initCounter+"]";
+        }
+        
+        public static Type getType(int attachmentPoint, int maxColorAttachments) {
+            if( GL.GL_COLOR_ATTACHMENT0 <= attachmentPoint && attachmentPoint < GL.GL_COLOR_ATTACHMENT0+maxColorAttachments ) {
+                return Type.COLOR;
+            }
+            switch(attachmentPoint) {
+                case GL.GL_DEPTH_ATTACHMENT:
+                    return Type.DEPTH;
+                case GL.GL_STENCIL_ATTACHMENT:            
+                    return Type.STENCIL;
+                default: 
+                    throw new IllegalArgumentException("Invalid attachment point 0x"+Integer.toHexString(attachmentPoint));
+            }
+        }
+    }
+    
+    /** Other renderbuffer attachment which maybe a colorbuffer, depth or stencil. */
+    public static class RenderAttachment extends Attachment {
+        private int samples;
+        
+        /**
+         * @param type allowed types are {@link Type#DEPTH}, {@link Type#STENCIL} or {@link Type#COLOR}
+         * @param iFormat
+         * @param samples
+         * @param width
+         * @param height
+         * @param name
+         */
+        public RenderAttachment(Type type, int iFormat, int samples, int width, int height, int name) {
+            super(validateType(type), iFormat, width, height, name);
+            this.samples = samples;
+        }
+        
+        /** number of samples, or zero for no multisampling */
+        public final int getSamples() { return samples; }
+        /* pp */ final void setSamples(int s) { samples = s; }
+        
+        private static Type validateType(Type type) {
+            switch(type) {
+                case DEPTH:
+                case STENCIL:
+                case COLOR:
+                    return type;
+                default: 
+                    throw new IllegalArgumentException("Invalid type: "+type);
+            }
+        }
+        
+        /**
+         * <p>
+         * Comparison by {@link #type}, {@link #format}, {@link #samples}, {@link #width}, {@link #height} and {@link #name}.
+         * </p>
+         * {@inheritDoc}
+         */
+        @Override
+        public boolean equals(Object o) {
+            if( this == o ) return true;
+            if( ! ( o instanceof RenderAttachment ) ) return false;
+            return super.equals(o) &&
+                   samples == ((RenderAttachment)o).samples;
+        }
+        
+        /**
+         * <p>
+         * Hashed by {@link #type}, {@link #format}, {@link #samples}, {@link #width}, {@link #height} and {@link #name}.
+         * </p>
+         * {@inheritDoc}
+         */
+        @Override
+        public int hashCode() {
+            // 31 * x == (x << 5) - x
+            int hash = super.hashCode();
+            hash = ((hash << 5) - hash) + samples;
+            return hash;
+        }
+
+        @Override
+        public void initialize(GL gl) throws GLException {
+            super.initialize(gl);
+            if( 1 == getInitCounter() && 0 == getName() ) {
+                final int[] name = new int[] { -1 };
+                gl.glGenRenderbuffers(1, name, 0);
+                if( 0 == name[0] ) {
+                    throw new GLException("null renderbuffer, "+this);
+                }
+                setName(name[0]);
+                
+                gl.glBindRenderbuffer(GL.GL_RENDERBUFFER, getName());
+                if( samples > 0 ) {
+                    ((GL2GL3)gl).glRenderbufferStorageMultisample(GL.GL_RENDERBUFFER, samples, format, getWidth(), getHeight());            
+                } else {
+                    gl.glRenderbufferStorage(GL.GL_RENDERBUFFER, format, getWidth(), getHeight());
+                }
+                int glerr = gl.glGetError();
+                if(GL.GL_NO_ERROR != glerr) {
+                    gl.glDeleteRenderbuffers(1, name, 0);
+                    setName(0);
+                    throw new GLException("GL Error 0x"+Integer.toHexString(glerr)+" while creating "+this);
+                }
+                resourceOwner = true;
+                if(DEBUG) {
+                    System.err.println("Attachment.init: "+this);
+                }
+            }
+        }
+        
+        @Override
+        public void free(GL gl) {
+            if(1 == getInitCounter() && resourceOwner && 0 != getName() ) {
+                final int[] name = new int[] { getName() };
+                gl.glDeleteRenderbuffers(1, name, 0);
+            }
+            super.free(gl);
+        }
+        
+        public String toString() {
+            return getClass().getSimpleName()+"[type "+type+", format 0x"+Integer.toHexString(format)+", samples "+samples+", "+getWidth()+"x"+getHeight()+
+                   ", name 0x"+Integer.toHexString(getName())+", obj 0x"+Integer.toHexString(objectHashCode())+
+                   ", resOwner "+resourceOwner+", initCount "+getInitCounter()+"]";
+        }
+    }
+    
+    /** 
+     * Marker interface, denotes a color buffer attachment.
+     * <p>Always an instance of {@link Attachment}.</p>
+     * <p>Either an instance of {@link ColorAttachment} or {@link TextureAttachment}.</b> 
+     */
+    public static interface Colorbuffer {        
+    }
+    
+    /** Color render buffer attachment  */
+    public static class ColorAttachment extends RenderAttachment implements Colorbuffer {
+        public ColorAttachment(int iFormat, int samples, int width, int height, int name) {
+            super(Type.COLOR, iFormat, samples, width, height, name);
+        }    
+    }
+    
+    /** Texture attachment */
+    public static class TextureAttachment extends Attachment implements Colorbuffer  {
+        /** details of the texture setup */
+        public final int dataFormat, dataType, magFilter, minFilter, wrapS, wrapT;
+
+        /**
+         * @param type allowed types are [ {@link Type#COLOR_TEXTURE}, {@link Type#DEPTH_TEXTURE}, {@link Type#STENCIL_TEXTURE} ]
+         * @param iFormat
+         * @param width
+         * @param height
+         * @param dataFormat
+         * @param dataType
+         * @param magFilter
+         * @param minFilter
+         * @param wrapS
+         * @param wrapT
+         * @param name
+         */
+        public TextureAttachment(Type type, int iFormat, int width, int height, int dataFormat, int dataType, 
+                                 int magFilter, int minFilter, int wrapS, int wrapT, int name) {
+            super(validateType(type), iFormat, width, height, name);
+            this.dataFormat = dataFormat;
+            this.dataType = dataType;
+            this.magFilter = magFilter;
+            this.minFilter = minFilter;
+            this.wrapS = wrapS;
+            this.wrapT = wrapT;
+        }
+        
+        private static Type validateType(Type type) {
+            switch(type) {
+                case COLOR_TEXTURE:
+                case DEPTH_TEXTURE:
+                case STENCIL_TEXTURE:
+                    return type;
+                default: 
+                    throw new IllegalArgumentException("Invalid type: "+type);
+            }
+        }
+        
+        /** 
+         * Initializes the texture and set it's parameter, if uninitialized, i.e. name is <code>zero</code>.
+         * @throws GLException if texture generation and setup fails. The just created texture name will be deleted in this case. 
+         */
+        @Override
+        public void initialize(GL gl) throws GLException {
+            super.initialize(gl);
+            if( 1 == getInitCounter() && 0 == getName() ) {
+                final int[] name = new int[] { -1 };            
+                gl.glGenTextures(1, name, 0);
+                if(0 == name[0]) {
+                    throw new GLException("null texture, "+this);
+                }
+                setName(name[0]);
+                
+                gl.glBindTexture(GL.GL_TEXTURE_2D, name[0]);
+                gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, format, getWidth(), getHeight(), 0, dataFormat, dataType, null);
+                if( 0 < magFilter ) {
+                    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, magFilter);
+                }
+                if( 0 < minFilter ) {
+                    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, minFilter);
+                }
+                if( 0 < wrapS ) {
+                    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, wrapS);
+                }
+                if( 0 < wrapT ) {
+                    gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, wrapT);            
+                }        
+                int glerr = gl.glGetError();
+                if(GL.GL_NO_ERROR != glerr) {
+                    gl.glDeleteTextures(1, name, 0);
+                    setName(0);
+                    throw new GLException("GL Error 0x"+Integer.toHexString(glerr)+" while creating "+this);
+                }
+                resourceOwner = true;
+            }
+            if(DEBUG) {
+                System.err.println("Attachment.init: "+this);
+            }
+        }
+
+        @Override
+        public void free(GL gl) {
+            if(1 == getInitCounter() && resourceOwner && 0 != getName() ) {
+                final int[] name = new int[] { getName() };
+                gl.glDeleteTextures(1, name, 0);
+            }
+            super.free(gl);
+        }
+    }
+    
+    private boolean initialized;
+    private boolean basicFBOSupport;
+    private boolean fullFBOSupport;
+    private boolean rgba8Avail;
+    private boolean depth24Avail;
+    private boolean depth32Avail;
+    private boolean stencil01Avail;
+    private boolean stencil04Avail;
+    private boolean stencil08Avail;
+    private boolean stencil16Avail;
+    private boolean packedDepthStencilAvail;            
+    private int maxColorAttachments, maxSamples, maxTextureSize, maxRenderbufferSize;
+
+    private int width, height, samples;
+    private int vStatus;
+    private int fbName;
+    private boolean bound;
+
+    private int colorAttachmentCount;
+    private Colorbuffer[] colorAttachmentPoints; // colorbuffer attachment points 
+    private RenderAttachment depth, stencil; // depth and stencil maybe equal in case of packed-depth-stencil
+
+    private final FBObject samplesSink; // MSAA sink
+    private TextureAttachment samplesSinkTexture; 
+    private boolean samplesSinkDirty;
+
+    //
+    // ColorAttachment helper ..
+    //
+    
+    private final void validateColorAttachmentPointRange(int point) {
+        if(maxColorAttachments != colorAttachmentPoints.length) {
+            throw new InternalError("maxColorAttachments "+maxColorAttachments+", array.lenght "+colorAttachmentPoints);
+        }
+        if(0 > point || point >= maxColorAttachments) {
+            throw new IllegalArgumentException("attachment point out of range: "+point+", should be within [0.."+(maxColorAttachments-1)+"]");
+        }
+    }
+    
+    private final void validateAddColorAttachment(int point, Colorbuffer ca) {
+        validateColorAttachmentPointRange(point);
+        if( null != colorAttachmentPoints[point] ) {
+            throw new IllegalArgumentException("Cannot attach "+ca+", attachment point already in use by "+colorAttachmentPoints[point]);
+        }        
+    }
+    
+    private final void addColorAttachment(int point, Colorbuffer ca) {
+        validateColorAttachmentPointRange(point);
+        final Colorbuffer c = colorAttachmentPoints[point];
+        if( null != c && c != ca ) {
+            throw new IllegalArgumentException("Add failed: requested to add "+ca+" at "+point+", but slot is holding "+c+"; "+this);
+        }
+        colorAttachmentPoints[point] = ca;
+        colorAttachmentCount++;
+    }
+    
+    private final void removeColorAttachment(int point, Colorbuffer ca) {
+        validateColorAttachmentPointRange(point);
+        final Colorbuffer c = colorAttachmentPoints[point];
+        if( null != c && c != ca ) {
+            throw new IllegalArgumentException("Remove failed: requested to removed "+ca+" at "+point+", but slot is holding "+c+"; "+this);
+        }
+        colorAttachmentPoints[point] = null;
+        colorAttachmentCount--;
+    }
+    
+    /**
+     * Return the {@link Colorbuffer} attachment at <code>attachmentPoint</code> if it is attached to this FBO, otherwise null.
+     * 
+     * @see #attachColorbuffer(GL, boolean)
+     * @see #attachColorbuffer(GL, boolean)
+     * @see #attachTexture2D(GL, int, boolean, int, int, int, int)
+     * @see #attachTexture2D(GL, int, int, int, int, int, int, int, int) 
+     */
+    public final Colorbuffer getColorbuffer(int attachmentPoint) {
+        validateColorAttachmentPointRange(attachmentPoint);        
+        return colorAttachmentPoints[attachmentPoint];
+    }
+    
+    /**
+     * Finds the passed {@link Colorbuffer} within the valid range of attachment points
+     * using <i>reference</i> comparison only.
+     * <p>
+     * Note: Slow. Implementation uses a logN array search to save resources, i.e. not using a HashMap.
+     * </p>
+     * @param ca the {@link Colorbuffer} to look for.
+     * @return -1 if the {@link Colorbuffer} could not be found, otherwise [0..{@link #getMaxColorAttachments()}-1] 
+     */
+    public final int getColorbufferAttachmentPoint(Colorbuffer ca) {
+        for(int i=0; i<colorAttachmentPoints.length; i++) {
+            if( colorAttachmentPoints[i] == ca ) {
+                return i; 
+            }
+        }
+        return -1;
+    }
+    
+    /**
+     * Returns the passed {@link Colorbuffer} if it is attached to this FBO, otherwise null.
+     * Implementation compares the <i>reference</i> only.
+     * 
+     * <p>
+     * Note: Slow. Uses {@link #getColorbufferAttachmentPoint(Colorbuffer)} to determine it's attachment point
+     *       to be used for {@link #getColorbuffer(int)}
+     * </p>
+     * 
+     * @see #attachColorbuffer(GL, boolean)
+     * @see #attachColorbuffer(GL, boolean)
+     * @see #attachTexture2D(GL, int, boolean, int, int, int, int)
+     * @see #attachTexture2D(GL, int, int, int, int, int, int, int, int) 
+     */
+    public final Colorbuffer getColorbuffer(Colorbuffer ca) {
+        final int p = getColorbufferAttachmentPoint(ca);
+        return p>=0 ? getColorbuffer(p) : null;
+    }
+        
+    /**
+     * Creates an uninitialized FBObject instance.
+     * <p>
+     * Call {@link #init(GL, int, int, int)} .. etc to use it.
+     * </p>
+     */
+    public FBObject() {
+        this(false);
+    }
+    /* pp */ FBObject(boolean isSampleSink) {
+        this.initialized = false;
+        
+        // TBD @ init
+        this.basicFBOSupport = false;
+        this.fullFBOSupport = false;
+        this.rgba8Avail = false;
+        this.depth24Avail = false;
+        this.depth32Avail = false;
+        this.stencil01Avail = false;
+        this.stencil04Avail = false;
+        this.stencil08Avail = false;
+        this.stencil16Avail = false;
+        this.packedDepthStencilAvail = false;
+        this.maxColorAttachments=-1;
+        this.maxSamples=-1;
+        this.maxTextureSize = 0;
+        this.maxRenderbufferSize = 0;
+        
+        this.width = 0;
+        this.height = 0;
+        this.samples = 0;
+        this.vStatus = -1;        
+        this.fbName = 0;
+        this.bound = false;
+        
+        this.colorAttachmentPoints = null; // at init ..
+        this.colorAttachmentCount = 0;
+        this.depth = null;
+        this.stencil = null;                
+        
+        this.samplesSink = isSampleSink ? null : new FBObject(true);
+        this.samplesSinkTexture = null;
+        this.samplesSinkDirty = true;
+    }
+    
+    private void init(GL gl, int width, int height, int samples) throws GLException {
+        if(initialized) {
+            throw new GLException("FBO already initialized");
+        }        
+        fullFBOSupport = supportsFullFBO(gl);
+        
+        if( !fullFBOSupport && !supportsBasicFBO(gl) ) {
+            throw new GLException("FBO not supported w/ context: "+gl.getContext()+", "+this);
+        }
+        
+        basicFBOSupport = true;
+        
+        rgba8Avail = gl.isGL2GL3() || gl.isExtensionAvailable(GLExtensions.OES_rgb8_rgba8);
+        depth24Avail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_depth24);
+        depth32Avail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_depth32);
+        stencil01Avail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_stencil1);
+        stencil04Avail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_stencil4);
+        stencil08Avail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_stencil8);
+        stencil16Avail = fullFBOSupport;
+        
+        packedDepthStencilAvail = fullFBOSupport || gl.isExtensionAvailable(GLExtensions.OES_packed_depth_stencil);
+        
+        final boolean NV_fbo_color_attachments = gl.isExtensionAvailable(GLExtensions.NV_fbo_color_attachments);
+                                
+        int val[] = new int[1];
+        
+        int glerr = gl.glGetError();
+        if(DEBUG && GL.GL_NO_ERROR != glerr) {
+            System.err.println("FBObject.init-preexisting.0 GL Error 0x"+Integer.toHexString(glerr));
+        }
+
+        int realMaxColorAttachments = 1;
+        maxColorAttachments = 1;
+        if( null != samplesSink && fullFBOSupport || NV_fbo_color_attachments ) {
+            try {
+                gl.glGetIntegerv(GL2GL3.GL_MAX_COLOR_ATTACHMENTS, val, 0);
+                glerr = gl.glGetError();
+                if(GL.GL_NO_ERROR == glerr) {
+                    realMaxColorAttachments = 1 <= val[0] ? val[0] : 1; // cap minimum to 1
+                } else if(DEBUG) {
+                    System.err.println("FBObject.init-GL_MAX_COLOR_ATTACHMENTS query GL Error 0x"+Integer.toHexString(glerr));
+                }
+            } catch (GLException gle) {}
+        }
+        maxColorAttachments = realMaxColorAttachments <= 8 ? realMaxColorAttachments : 8; // cap to limit array size
+        
+        colorAttachmentPoints = new Colorbuffer[maxColorAttachments];
+        colorAttachmentCount = 0;
+        
+        maxSamples = 0;
+        if(fullFBOSupport) {
+            gl.glGetIntegerv(GL2GL3.GL_MAX_SAMPLES, val, 0);
+            glerr = gl.glGetError();
+            if(GL.GL_NO_ERROR == glerr) {
+                maxSamples = val[0];
+            } else if(DEBUG) {
+                System.err.println("FBObject.init-GL_MAX_SAMPLES query GL Error 0x"+Integer.toHexString(glerr));
+            }
+        }
+        gl.glGetIntegerv(GL.GL_MAX_TEXTURE_SIZE, val, 0);
+        maxTextureSize = val[0];
+        gl.glGetIntegerv(GL.GL_MAX_RENDERBUFFER_SIZE, val, 0);
+        this.maxRenderbufferSize = val[0];
+        
+        glerr = gl.glGetError();
+        if(DEBUG && GL.GL_NO_ERROR != glerr) {
+            System.err.println("FBObject.init-preexisting.1 GL Error 0x"+Integer.toHexString(glerr));
+        }
+        
+        this.width = width;
+        this.height = height;
+        this.samples = samples <= maxSamples ? samples : maxSamples;
+        
+        if(DEBUG) {
+            System.err.println("FBObject "+width+"x"+height+", "+samples+" -> "+samples+" samples");
+            System.err.println("basicFBOSupport:          "+basicFBOSupport);
+            System.err.println("fullFBOSupport:           "+fullFBOSupport);
+            System.err.println("maxColorAttachments:      "+maxColorAttachments+"/"+realMaxColorAttachments);
+            System.err.println("maxSamples:               "+maxSamples);
+            System.err.println("maxTextureSize:           "+maxTextureSize);
+            System.err.println("maxRenderbufferSize:      "+maxRenderbufferSize);
+            System.err.println("rgba8:                    "+rgba8Avail);
+            System.err.println("depth24:                  "+depth24Avail);
+            System.err.println("depth32:                  "+depth32Avail);
+            System.err.println("stencil01:                "+stencil01Avail);
+            System.err.println("stencil04:                "+stencil04Avail);
+            System.err.println("stencil08:                "+stencil08Avail);
+            System.err.println("stencil16:                "+stencil16Avail);
+            System.err.println("packedDepthStencil:       "+packedDepthStencilAvail);
+            System.err.println("NV_fbo_color_attachments: "+NV_fbo_color_attachments);
+            System.err.println(gl.getContext().getGLVersion());
+            System.err.println(JoglVersion.getGLStrings(gl, null).toString());
+            System.err.println(gl.getContext());
+        }
+        
+        checkNoError(null, gl.glGetError(), "FBObject Init.pre"); // throws GLException if error
+        
+        if(width > 2 + maxTextureSize  || height> 2 + maxTextureSize ||
+           width > maxRenderbufferSize || height> maxRenderbufferSize  ) {
+            throw new GLException("size "+width+"x"+height+" exceeds on of the maxima [texture "+maxTextureSize+", renderbuffer "+maxRenderbufferSize+"]");
+        }
+
+        if(null != samplesSink) {        
+            // init sampling sink
+            samplesSink.reset(gl, width, height);
+            resetMSAATexture2DSink(gl);
+        }
+
+        // generate fbo ..
+        gl.glGenFramebuffers(1, val, 0);
+        fbName = val[0];
+        if(0 == fbName) {
+            throw new GLException("null framebuffer");
+        }
+
+        // bind fbo ..
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, fbName);        
+        checkNoError(gl, gl.glGetError(), "FBObject Init.bindFB");  // throws GLException if error        
+        if(!gl.glIsFramebuffer(fbName)) {
+            checkNoError(gl, GL.GL_INVALID_VALUE, "FBObject Init.isFB"); // throws GLException
+        }
+        bound = true;        
+        initialized = true;
+        
+        updateStatus(gl);
+        if(DEBUG) {
+            System.err.println("FBObject.init(): "+this);
+        }
+    }
+
+    /**
+     * Initializes or resets this FBO's instance.
+     * <p>
+     * In case the new parameters are compatible with the current ones
+     * no action will be performed. Otherwise all attachments will be recreated
+     * to match the new given parameters.
+     * </p>
+     * <p>
+     * Currently incompatibility and hence recreation is given if
+     * the size or sample count doesn't match for subsequent calls.
+     * </p>
+     * 
+     * <p>Leaves the FBO bound state untouched</p>
+     * 
+     * @param gl the current GL context
+     * @param newWidth
+     * @param newHeight
+     * @throws GLException in case of an error
+     */
+    public final void reset(GL gl, int newWidth, int newHeight) {
+        reset(gl, newWidth, newHeight, 0);
+    }
+    
+    /**
+     * Initializes or resets this FBO's instance.
+     * <p>
+     * In case the new parameters are compatible with the current ones
+     * no action will be performed. Otherwise all attachments will be recreated
+     * to match the new given parameters.
+     * </p>
+     * <p>
+     * Currently incompatibility and hence recreation is given if
+     * the size or sample count doesn't match for subsequent calls.
+     * </p>
+     * 
+     * <p>Leaves the FBO bound state untouched</p>
+     * 
+     * @param gl the current GL context
+     * @param newWidth
+     * @param newHeight
+     * @param newSamples if > 0, MSAA will be used, otherwise no multisampling. Will be capped to {@link #getMaxSamples()}.
+     * @throws GLException in case of an error
+     */
+    public final void reset(GL gl, int newWidth, int newHeight, int newSamples) {
+        if(!initialized) {
+            init(gl, newWidth, newHeight, newSamples);
+            return;
+        }
+        newSamples = newSamples <= maxSamples ? newSamples : maxSamples; // clamp
+        
+        if( newWidth !=  width || newHeight !=  height || newSamples != samples ) {
+            if(DEBUG) {
+                System.err.println("FBObject.reset - START - "+this);
+            }        
+            
+            final boolean wasBound = isBound();
+            
+            width = newWidth;
+            height = newHeight;
+            samples = newSamples;
+            detachAllImpl(gl, true , true);
+            resetMSAATexture2DSink(gl);
+            
+            if(wasBound) {
+                bind(gl);
+            } else {
+                unbind(gl);
+            }
+            
+            if(DEBUG) {
+                System.err.println("FBObject.reset - END - "+this);
+            }
+        }        
+    }
+            
+    /** 
+     * Note that the status may reflect an incomplete state during transition of attachments.
+     * @return The FB status. {@link GL.GL_FRAMEBUFFER_COMPLETE} if ok, otherwise return GL FBO error state or -1
+     * @see #validateStatus() 
+     */
+    public final int getStatus() {
+        return vStatus;
+    }
+
+    /** return the {@link #getStatus()} as a string. */
+    public final String getStatusString() {
+        return getStatusString(vStatus);
+    }
+    
+    public static final String getStatusString(int fbStatus) {
+        switch(fbStatus) {
+            case -1:
+                return "NOT A FBO";
+                
+            case GL.GL_FRAMEBUFFER_COMPLETE:
+                return "OK";
+                
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
+                return("GL FBO: incomplete, incomplete attachment\n");
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
+                return("GL FBO: incomplete, missing attachment");
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
+                return("GL FBO: incomplete, attached images must have same dimensions");
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_FORMATS:
+                 return("GL FBO: incomplete, attached images must have same format");
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
+                return("GL FBO: incomplete, missing draw buffer");
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
+                return("GL FBO: incomplete, missing read buffer");
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
+                return("GL FBO: incomplete, missing multisample buffer");
+            case GL3.GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:                
+                return("GL FBO: incomplete, layer targets");
+                
+            case GL.GL_FRAMEBUFFER_UNSUPPORTED:
+                return("GL FBO: Unsupported framebuffer format");
+            case GL2GL3.GL_FRAMEBUFFER_UNDEFINED:
+                 return("GL FBO: framebuffer undefined");
+                 
+            case 0:
+                return("GL FBO: incomplete, implementation fault");
+            default:
+                return("GL FBO: incomplete, implementation ERROR 0x"+Integer.toHexString(fbStatus));
+        }
+    }
+    
+    /**
+     * The status may even be valid if incomplete during transition of attachments.
+     * @see #getStatus()
+     */
+    public final boolean isStatusValid() {
+        switch(vStatus) {
+            case GL.GL_FRAMEBUFFER_COMPLETE:
+                return true;
+                
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
+            case GL.GL_FRAMEBUFFER_INCOMPLETE_FORMATS:
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
+            case GL2GL3.GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
+            case GL3.GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:
+                if(0 == colorAttachmentCount || null == depth) {
+                    // we are in transition
+                    return true;
+                }
+         
+            case GL.GL_FRAMEBUFFER_UNSUPPORTED:
+            case GL2GL3.GL_FRAMEBUFFER_UNDEFINED:
+                
+            case 0:                
+            default:
+                System.out.println("Framebuffer " + fbName + " is incomplete: status = 0x" + Integer.toHexString(vStatus) + 
+                        " : " + getStatusString(vStatus));
+                return false;
+        }
+    }
+        
+    private final boolean checkNoError(GL gl, int err, String exceptionMessage) throws GLException {
+        if(GL.GL_NO_ERROR != err) {
+            if(null != gl) {
+                destroy(gl);
+            }
+            if(null != exceptionMessage) {
+                throw new GLException(exceptionMessage+" GL Error 0x"+Integer.toHexString(err));
+            }
+            return false;
+        }
+        return true;
+    }
+
+    private final void checkInitialized() throws GLException {
+        if(!initialized) {
+            throw new GLException("FBO not initialized, call init(GL) first.");
+        }                
+    }
+    
+    /**
+     * Attaches a Texture2D Color Buffer to this FBO's instance at the given attachment point,
+     * selecting the texture data type and format automatically.
+     * 
+     * <p>Using default min/mag filter {@link GL#GL_NEAREST} and default wrapS/wrapT {@link GL#GL_CLAMP_TO_EDGE}.</p>
+     * 
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param alpha set to <code>true</code> if you request alpha channel, otherwise <code>false</code>;
+     * @return TextureAttachment instance describing the new attached texture colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the texture colorbuffer couldn't be allocated or MSAA has been chosen
+     */
+    public final TextureAttachment attachTexture2D(GL gl, int attachmentPoint, boolean alpha) throws GLException {
+        return attachTexture2D(gl, attachmentPoint, alpha, GL.GL_NEAREST, GL.GL_NEAREST, GL.GL_CLAMP_TO_EDGE, GL.GL_CLAMP_TO_EDGE);
+    }
+    
+    /**
+     * Attaches a Texture2D Color Buffer to this FBO's instance at the given attachment point,
+     * selecting the texture data type and format automatically.
+     * 
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param alpha set to <code>true</code> if you request alpha channel, otherwise <code>false</code>;
+     * @param magFilter if > 0 value for {@link GL#GL_TEXTURE_MAG_FILTER}
+     * @param minFilter if > 0 value for {@link GL#GL_TEXTURE_MIN_FILTER} 
+     * @param wrapS if > 0 value for {@link GL#GL_TEXTURE_WRAP_S}
+     * @param wrapT if > 0 value for {@link GL#GL_TEXTURE_WRAP_T}
+     * @return TextureAttachment instance describing the new attached texture colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the texture colorbuffer couldn't be allocated or MSAA has been chosen
+     */
+    public final TextureAttachment attachTexture2D(GL gl, int attachmentPoint, boolean alpha, int magFilter, int minFilter, int wrapS, int wrapT) throws GLException {
+        final int textureInternalFormat, textureDataFormat, textureDataType;
+        if(gl.isGLES()) { 
+            textureInternalFormat = alpha ? GL.GL_RGBA : GL.GL_RGB;
+            textureDataFormat = alpha ? GL.GL_RGBA : GL.GL_RGB;
+            textureDataType = GL.GL_UNSIGNED_BYTE;
+        } else { 
+            textureInternalFormat = alpha ? GL.GL_RGBA8 : GL.GL_RGB8;
+            textureDataFormat = alpha ? GL.GL_BGRA : GL.GL_RGB;
+            textureDataType = alpha ? GL2GL3.GL_UNSIGNED_INT_8_8_8_8_REV : GL.GL_UNSIGNED_BYTE;
+        }
+        return attachTexture2D(gl, attachmentPoint, textureInternalFormat, textureDataFormat, textureDataType, magFilter, minFilter, wrapS, wrapT);
+    }
+    
+    /**
+     * Attaches a Texture2D Color Buffer to this FBO's instance at the given attachment point.
+     * 
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param internalFormat internalFormat parameter to {@link GL#glTexImage2D(int, int, int, int, int, int, int, int, long)}
+     * @param dataFormat format parameter to {@link GL#glTexImage2D(int, int, int, int, int, int, int, int, long)}
+     * @param dataType type parameter to {@link GL#glTexImage2D(int, int, int, int, int, int, int, int, long)}
+     * @param magFilter if > 0 value for {@link GL#GL_TEXTURE_MAG_FILTER}
+     * @param minFilter if > 0 value for {@link GL#GL_TEXTURE_MIN_FILTER} 
+     * @param wrapS if > 0 value for {@link GL#GL_TEXTURE_WRAP_S}
+     * @param wrapT if > 0 value for {@link GL#GL_TEXTURE_WRAP_T}
+     * @return TextureAttachment instance describing the new attached texture colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the texture colorbuffer couldn't be allocated or MSAA has been chosen
+     */
+    public final TextureAttachment attachTexture2D(GL gl, int attachmentPoint,
+                                                   int internalFormat, int dataFormat, int dataType,
+                                                   int magFilter, int minFilter, int wrapS, int wrapT) throws GLException {
+        return attachTexture2D(gl, attachmentPoint, 
+                               new TextureAttachment(Type.COLOR_TEXTURE, internalFormat, width, height, dataFormat, dataType, 
+                                                     magFilter, minFilter, wrapS, wrapT, 0 /* name */));
+    }
+    
+    /**
+     * Attaches a Texture2D Color Buffer to this FBO's instance at the given attachment point.
+     *  
+     * <p>
+     * In case the passed TextureAttachment <code>texA</code> is uninitialized, i.e. it's texture name is <code>zero</code>,
+     * a new texture name is generated and setup w/ the texture parameter.<br/>
+     * Otherwise, i.e. texture name is not <code>zero</code>, the passed TextureAttachment <code>texA</code> is
+     * considered complete and assumed matching this FBO requirement. A GL error may occur is the latter is untrue. 
+     * </p>
+     *    
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param texA the to be attached {@link TextureAttachment}. Maybe complete or uninitialized, see above. 
+     * @return the passed TextureAttachment <code>texA</code> instance describing the new attached texture colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the texture colorbuffer couldn't be allocated or MSAA has been chosen
+     */
+    public final TextureAttachment attachTexture2D(GL gl, int attachmentPoint, TextureAttachment texA) throws GLException {
+        validateAddColorAttachment(attachmentPoint, texA);
+        
+        if(samples>0) {
+            removeColorAttachment(attachmentPoint, texA);
+            throw new GLException("Texture2D not supported w/ MSAA. If you have enabled MSAA with exisiting texture attachments, you may want to detach them via detachAllTexturebuffer(gl).");
+        }
+        
+        texA.initialize(gl);
+        addColorAttachment(attachmentPoint, texA);
+                
+        bind(gl);
+
+        // Set up the color buffer for use as a renderable texture:
+        gl.glFramebufferTexture2D(GL.GL_FRAMEBUFFER,
+                                  GL.GL_COLOR_ATTACHMENT0 + attachmentPoint,
+                                  GL.GL_TEXTURE_2D, texA.getName(), 0);
+        updateStatus(gl);
+        
+        if(!isStatusValid()) {
+            detachColorbuffer(gl, attachmentPoint);
+            throw new GLException("attachTexture2D "+texA+" at "+attachmentPoint+" failed "+getStatusString()+", "+this);
+        }
+        if(DEBUG) {
+            System.err.println("FBObject.attachTexture2D: "+this);
+        }
+        return texA;
+    }
+    
+    /**
+     * Attaches a Color Buffer to this FBO's instance at the given attachment point,
+     * selecting the format automatically.
+     *  
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param alpha set to <code>true</code> if you request alpha channel, otherwise <code>false</code>;
+     * @return ColorAttachment instance describing the new attached colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the colorbuffer couldn't be allocated
+     */
+    public final ColorAttachment attachColorbuffer(GL gl, int attachmentPoint, boolean alpha) throws GLException {
+        final int internalFormat;
+        if( rgba8Avail ) {
+            internalFormat = alpha ? GL.GL_RGBA8 : GL.GL_RGB8 ;
+        } else {
+            internalFormat = alpha ? GL.GL_RGBA4 : GL.GL_RGB565;
+        }
+        return attachColorbuffer(gl, attachmentPoint, internalFormat);
+    }
+    
+    /**
+     * Attaches a Color Buffer to this FBO's instance at the given attachment point.
+     *  
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param internalFormat usually {@link GL#GL_RGBA4}, {@link GL#GL_RGB5_A1}, {@link GL#GL_RGB565}, {@link GL#GL_RGB8} or {@link GL#GL_RGBA8}  
+     * @return ColorAttachment instance describing the new attached colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the colorbuffer couldn't be allocated
+     * @throws IllegalArgumentException if <code>internalFormat</code> doesn't reflect a colorbuffer
+     */
+    public final ColorAttachment attachColorbuffer(GL gl, int attachmentPoint, int internalFormat) throws GLException, IllegalArgumentException {
+        final Attachment.Type atype = Attachment.Type.determine(internalFormat);
+        if( Attachment.Type.COLOR != atype ) {
+            throw new IllegalArgumentException("colorformat invalid: 0x"+Integer.toHexString(internalFormat)+", "+this);
+        }
+        
+        return attachColorbuffer(gl, attachmentPoint, new ColorAttachment(internalFormat, samples, width, height, 0));
+    }
+    
+    /**
+     * Attaches a Color Buffer to this FBO's instance at the given attachment point.
+     *  
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl
+     * @param attachmentPoint the color attachment point ranging from [0..{@link #getMaxColorAttachments()}-1]
+     * @param colA the template for the new {@link ColorAttachment}   
+     * @return ColorAttachment instance describing the new attached colorbuffer if bound and configured successfully, otherwise GLException is thrown
+     * @throws GLException in case the colorbuffer couldn't be allocated
+     */
+    public final ColorAttachment attachColorbuffer(GL gl, int attachmentPoint, ColorAttachment colA) throws GLException {
+        validateAddColorAttachment(attachmentPoint, colA);
+        
+        colA.initialize(gl);        
+        addColorAttachment(attachmentPoint, colA);
+        
+        bind(gl);
+                
+        // Attach the color buffer
+        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, 
+                                     GL.GL_COLOR_ATTACHMENT0 + attachmentPoint, 
+                                     GL.GL_RENDERBUFFER, colA.getName());
+
+        updateStatus(gl);                
+        if(!isStatusValid()) {
+            detachColorbuffer(gl, attachmentPoint);
+            throw new GLException("attachColorbuffer "+colA+" at "+attachmentPoint+" failed "+getStatusString()+", "+this);
+        }
+        if(DEBUG) {
+            System.err.println("FBObject.attachColorbuffer: "+this);
+        }
+        return colA;
+    }
+
+    
+    /**
+     * Attaches one depth, stencil or packed-depth-stencil buffer to this FBO's instance,
+     * selecting the internalFormat automatically.
+     * <p>
+     * Stencil and depth buffer can be attached only once.
+     * </p>
+     * <p>
+     * In case the desired type or bit-number is not supported, the next available one is chosen.
+     * </p>  
+     * <p>
+     * Use {@link #getDepthAttachment()} and/or {@link #getStencilAttachment()} to retrieve details
+     * about the attached buffer. The details cannot be returned, since it's possible 2 buffers
+     * are being created, depth and stencil.
+     * </p>
+     * 
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl
+     * @param atype either {@link Type#DEPTH}, {@link Type#STENCIL} or {@link Type#DEPTH_STENCIL}  
+     * @param reqBits desired bits for depth or -1 for default (24 bits)
+     * @throws GLException in case the renderbuffer couldn't be allocated or one is already attached.
+     * @throws IllegalArgumentException
+     * @see #getDepthAttachment()
+     * @see #getStencilAttachment()
+     */
+    public final void attachRenderbuffer(GL gl, Attachment.Type atype, int reqBits) throws GLException, IllegalArgumentException {        
+        if( 0 > reqBits ) {
+            reqBits = 24;
+        }        
+        final int internalFormat;
+        int internalStencilFormat = -1;
+        
+        switch ( atype ) {
+            case DEPTH:
+                if( 32 <= reqBits && depth32Avail ) {
+                    internalFormat = GL.GL_DEPTH_COMPONENT32;
+                } else if( 24 <= reqBits && depth24Avail ) {
+                    internalFormat = GL.GL_DEPTH_COMPONENT24;
+                } else {
+                    internalFormat = GL.GL_DEPTH_COMPONENT16;                    
+                }
+                break;
+                
+            case STENCIL:
+                if( 16 <= reqBits && stencil16Avail ) {
+                    internalFormat = GL2GL3.GL_STENCIL_INDEX16;
+                } else if( 8 <= reqBits && stencil08Avail ) {
+                    internalFormat = GL.GL_STENCIL_INDEX8;
+                } else if( 4 <= reqBits && stencil04Avail ) {
+                    internalFormat = GL.GL_STENCIL_INDEX4;
+                } else if( 1 <= reqBits && stencil01Avail ) {
+                    internalFormat = GL.GL_STENCIL_INDEX1;
+                } else {
+                    throw new GLException("stencil buffer n/a");        
+                }
+                break;
+                
+            case DEPTH_STENCIL:
+                if( packedDepthStencilAvail ) {
+                    internalFormat = GL.GL_DEPTH24_STENCIL8;
+                } else {
+                    if( 24 <= reqBits && depth24Avail ) {
+                        internalFormat = GL.GL_DEPTH_COMPONENT24;
+                    } else {
+                        internalFormat = GL.GL_DEPTH_COMPONENT16;                    
+                    }
+                    if( stencil08Avail ) {
+                        internalStencilFormat = GL.GL_STENCIL_INDEX8;
+                    } else if( stencil04Avail ) {
+                        internalStencilFormat = GL.GL_STENCIL_INDEX4;
+                    } else if( stencil01Avail ) {
+                        internalStencilFormat = GL.GL_STENCIL_INDEX1;
+                    } else {
+                        throw new GLException("stencil buffer n/a");
+                    }
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("only depth/stencil types allowed, was "+atype+", "+this);
+        }
+        
+        attachRenderbufferImpl(gl, atype, internalFormat);
+        
+        if(0<=internalStencilFormat) {
+            attachRenderbufferImpl(gl, Attachment.Type.STENCIL, internalStencilFormat);
+        }
+    }
+    
+    /**
+     * Attaches one depth, stencil or packed-depth-stencil buffer to this FBO's instance,
+     * depending on the <code>internalFormat</code>. 
+     * <p>
+     * Stencil and depth buffer can be attached only once.
+     * </p>
+     * <p>
+     * Use {@link #getDepthAttachment()} and/or {@link #getStencilAttachment()} to retrieve details
+     * about the attached buffer. The details cannot be returned, since it's possible 2 buffers
+     * are being created, depth and stencil.
+     * </p>
+     * 
+     * <p>Leaves the FBO bound.</p>
+     * 
+     * @param gl the current GL context
+     * @param internalFormat {@link GL#GL_DEPTH_COMPONENT16}, {@link GL#GL_DEPTH_COMPONENT24}, {@link GL#GL_DEPTH_COMPONENT32},
+     *                       {@link GL#GL_STENCIL_INDEX1}, {@link GL#GL_STENCIL_INDEX4}, {@link GL#GL_STENCIL_INDEX8}
+     *                       or {@link GL#GL_DEPTH24_STENCIL8}
+     * @throws GLException in case the renderbuffer couldn't be allocated or one is already attached.
+     * @throws IllegalArgumentException
+     * @see #getDepthAttachment()
+     * @see #getStencilAttachment()
+     */
+    public final void attachRenderbuffer(GL gl, int internalFormat) throws GLException, IllegalArgumentException {
+        final Attachment.Type atype = Attachment.Type.determine(internalFormat);
+        if( Attachment.Type.DEPTH != atype && Attachment.Type.STENCIL != atype && Attachment.Type.DEPTH_STENCIL != atype ) {
+            throw new IllegalArgumentException("renderformat invalid: 0x"+Integer.toHexString(internalFormat)+", "+this);
+        }
+        attachRenderbufferImpl(gl, atype, internalFormat);
+    }
+    
+    protected final void attachRenderbufferImpl(GL gl, Attachment.Type atype, int internalFormat) throws GLException {
+        if( null != depth && ( Attachment.Type.DEPTH == atype || Attachment.Type.DEPTH_STENCIL == atype ) ) {
+            throw new GLException("FBO depth buffer already attached (rb "+depth+"), type is "+atype+", 0x"+Integer.toHexString(internalFormat)+", "+this);
+        }        
+        if( null != stencil && ( Attachment.Type.STENCIL== atype || Attachment.Type.DEPTH_STENCIL == atype ) ) {
+            throw new GLException("FBO stencil buffer already attached (rb "+stencil+"), type is "+atype+", 0x"+Integer.toHexString(internalFormat)+", "+this);
+        }
+        attachRenderbufferImpl2(gl, atype, internalFormat);
+    }
+        
+    private final void attachRenderbufferImpl2(GL gl, Attachment.Type atype, int internalFormat) throws GLException {
+        if( Attachment.Type.DEPTH == atype ) {
+            if(null == depth) {
+                depth = new RenderAttachment(Type.DEPTH, internalFormat, samples, width, height, 0);
+            } else {
+                depth.setSize(width, height);
+                depth.setSamples(samples);
+            }
+            depth.initialize(gl);
+        } else if( Attachment.Type.STENCIL == atype ) {
+            if(null == stencil) {
+                stencil = new RenderAttachment(Type.STENCIL, internalFormat, samples, width, height, 0);
+            } else {
+                stencil.setSize(width, height);
+                stencil.setSamples(samples);
+            }
+            stencil.initialize(gl);
+        } else if( Attachment.Type.DEPTH_STENCIL == atype ) {
+            if(null == depth) {
+                depth = new RenderAttachment(Type.DEPTH, internalFormat, samples, width, height, 0);
+            } else {
+                depth.setSize(width, height);
+                depth.setSamples(samples);
+            }
+            depth.initialize(gl);
+            if(null == stencil) {
+                stencil = new RenderAttachment(Type.STENCIL, internalFormat, samples, width, height, depth.getName());
+            } else {
+                stencil.setName(depth.getName());
+                stencil.setSize(width, height);
+                stencil.setSamples(samples);
+            }
+            stencil.initialize(gl);
+        }
+
+        bind(gl);
+        
+        // Attach the buffer
+        if( Attachment.Type.DEPTH == atype ) {
+            gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_DEPTH_ATTACHMENT, GL.GL_RENDERBUFFER, depth.getName());
+        } else if( Attachment.Type.STENCIL == atype ) {
+            gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_STENCIL_ATTACHMENT, GL.GL_RENDERBUFFER, stencil.getName());
+        } else if( Attachment.Type.DEPTH_STENCIL == atype ) {
+            gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_DEPTH_ATTACHMENT, GL.GL_RENDERBUFFER, depth.getName());            
+            gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_STENCIL_ATTACHMENT, GL.GL_RENDERBUFFER, stencil.getName());
+        }
+        
+        updateStatus(gl);
+        if( !isStatusValid() ) {
+            detachRenderbuffer(gl, atype);
+            throw new GLException("renderbuffer attachment failed: "+this.getStatusString());
+        }
+
+        if(DEBUG) {
+            System.err.println("FBObject.attachRenderbuffer: "+this);
+        }
+    }
+    
+    /**
+     * <p>Leaves the FBO bound!</p>
+     * @param gl
+     * @param ca
+     * @throws IllegalArgumentException
+     */
+    public final void detachColorbuffer(GL gl, int attachmentPoint) throws IllegalArgumentException {
+        if(null == detachColorbufferImpl(gl, attachmentPoint, false)) {
+            throw new IllegalArgumentException("ColorAttachment at "+attachmentPoint+", not attached, "+this);            
+        }
+        if(DEBUG) {
+            System.err.println("FBObject.detachAll: "+this);
+        }
+    }
+    
+    private final Colorbuffer detachColorbufferImpl(GL gl, int attachmentPoint, boolean recreate) {
+        final Colorbuffer colbuf = colorAttachmentPoints[attachmentPoint]; // shortcut, don't validate here
+        
+        if(null == colbuf) {
+            return null;
+        }
+        
+        bind(gl);
+        
+        if(colbuf instanceof TextureAttachment) {
+            final TextureAttachment texA = (TextureAttachment) colbuf;
+            if( 0 != texA.getName() ) {
+                gl.glFramebufferTexture2D(GL.GL_FRAMEBUFFER,
+                              GL.GL_COLOR_ATTACHMENT0 + attachmentPoint,
+                              GL.GL_TEXTURE_2D, 0, 0);
+                gl.glBindTexture(GL.GL_TEXTURE_2D, 0);
+            }
+            texA.free(gl);
+            removeColorAttachment(attachmentPoint, texA);                
+            if(recreate) {
+                texA.setSize(width, height);
+                attachTexture2D(gl, attachmentPoint, texA);
+            }
+        } else if(colbuf instanceof ColorAttachment) {
+            final ColorAttachment colA = (ColorAttachment) colbuf;
+            if( 0 != colA.getName() ) {
+                gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, 
+                                             GL.GL_COLOR_ATTACHMENT0+attachmentPoint, 
+                                             GL.GL_RENDERBUFFER, 0);
+            }
+            colA.free(gl);
+            removeColorAttachment(attachmentPoint, colbuf);
+            if(recreate) {
+                colA.setSize(width, height);
+                colA.setSamples(samples);
+                attachColorbuffer(gl, attachmentPoint, colA);
+            }
+        }
+        return colbuf;
+    }
+    
+    /**
+     * 
+     * @param gl
+     * @param reqAType {@link Type#DEPTH}, {@link Type#DEPTH} or {@link Type#DEPTH_STENCIL} 
+     */
+    public final void detachRenderbuffer(GL gl, Attachment.Type atype) throws IllegalArgumentException {
+        detachRenderbufferImpl(gl, atype, false);
+    }
+    
+    public final boolean isDepthStencilPackedFormat() {
+        final boolean res = null != depth && null != stencil &&
+                            depth.format == stencil.format ;
+        if(res && depth.getName() != stencil.getName() ) {
+            throw new InternalError("depth/stencil packed format not sharing: depth "+depth+", stencil "+stencil);
+        }
+        return res;
+    }
+        
+    private final void detachRenderbufferImpl(GL gl, Attachment.Type atype, boolean recreate) throws IllegalArgumentException {
+        switch ( atype ) {
+            case DEPTH:
+            case STENCIL:
+            case DEPTH_STENCIL:             
+             break;
+             default:
+                 throw new IllegalArgumentException("only depth/stencil types allowed, was "+atype+", "+this);
+        }        
+        if( null == depth && null == stencil ) {
+            return ; // nop
+        } 
+        // reduction of possible combinations, create unique atype command(s)
+        final ArrayList<Attachment.Type> actions = new ArrayList<Attachment.Type>(2);  
+        if( isDepthStencilPackedFormat() ) {
+            // packed
+            actions.add(Attachment.Type.DEPTH_STENCIL);
+        } else {
+            // individual
+            switch ( atype ) {
+                case DEPTH:
+                    if( null != depth ) { actions.add(Attachment.Type.DEPTH); }
+                    break;
+                case STENCIL:
+                    if( null != stencil ) { actions.add(Attachment.Type.STENCIL); }
+                    break;
+                case DEPTH_STENCIL:
+                    if( null != depth ) { actions.add(Attachment.Type.DEPTH); }
+                    if( null != stencil ) { actions.add(Attachment.Type.STENCIL); }
+                    break;
+                 default: // handled
+            }
+        }
+        
+        bind(gl);        
+        
+        for(int i = 0; i < actions.size(); i++) {
+            final int format;
+            
+            Attachment.Type action = actions.get(i);
+            switch ( action ) {
+                case DEPTH:
+                    format = depth.format;
+                    if( 0 != depth.getName() ) {
+                        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_DEPTH_ATTACHMENT, GL.GL_RENDERBUFFER, 0);
+                    }
+                    depth.free(gl);
+                    if(!recreate) {
+                        depth = null;
+                    }
+                    break;
+                case STENCIL:
+                    format = stencil.format;
+                    if(0 != stencil.getName()) {
+                        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_STENCIL_ATTACHMENT, GL.GL_RENDERBUFFER, 0);
+                    }
+                    stencil.free(gl);
+                    if(!recreate) {
+                        stencil = null;
+                    }
+                    break;
+                case DEPTH_STENCIL:
+                    format = depth.format;
+                    if(0 != depth.getName()) {
+                        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_DEPTH_ATTACHMENT, GL.GL_RENDERBUFFER, 0);
+                        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_STENCIL_ATTACHMENT, GL.GL_RENDERBUFFER, 0);
+                    }
+                    depth.free(gl);
+                    stencil.free(gl);
+                    if(!recreate) {
+                        depth = null;
+                        stencil = null;
+                    }
+                    break;
+                 default:
+                    throw new InternalError("XXX");
+            }
+            if(recreate) {
+                attachRenderbufferImpl2(gl, action, format);
+            }
+        }        
+    }
+        
+    /** 
+     * Detaches all {@link ColorAttachment}s, {@link TextureAttachment}s and {@link RenderAttachment}s.
+     * <p>Leaves the FBO bound!</p>
+     * <p>
+     * An attached sampling sink texture will be detached as well, see {@link #getSamplingSink()}.
+     * </p> 
+     * @param gl the current GL context
+     */
+    public final void detachAll(GL gl) {
+        if(null != samplesSink) {
+            samplesSink.detachAll(gl);
+        }        
+        detachAllImpl(gl, true/* detachNonColorbuffer */, false /* recreate */);
+    }
+    
+    /** 
+     * Detaches all {@link ColorAttachment}s and {@link TextureAttachment}s.
+     * <p>Leaves the FBO bound!</p>
+     * <p>
+     * An attached sampling sink texture will be detached as well, see {@link #getSamplingSink()}.
+     * </p> 
+     * @param gl the current GL context
+     */
+    public final void detachAllColorbuffer(GL gl) {
+        if(null != samplesSink) {
+            samplesSink.detachAllColorbuffer(gl);
+        }        
+        detachAllImpl(gl, false/* detachNonColorbuffer */, false /* recreate */);
+    }
+    
+    /** 
+     * Detaches all {@link TextureAttachment}s 
+     * <p>Leaves the FBO bound!</p>
+     * <p>
+     * An attached sampling sink texture will be detached as well, see {@link #getSamplingSink()}.
+     * </p> 
+     * @param gl the current GL context
+     */
+    public final void detachAllTexturebuffer(GL gl) {
+        if(null != samplesSink) {
+            samplesSink.detachAllTexturebuffer(gl);
+        }
+        for(int i=0; i<maxColorAttachments; i++) {
+            if(colorAttachmentPoints[i] instanceof TextureAttachment) {
+                detachColorbufferImpl(gl, i, false);
+            }
+        }
+    }
+    
+    public final void detachAllRenderbuffer(GL gl) {
+        if(null != samplesSink) {
+            samplesSink.detachAllRenderbuffer(gl);
+        }
+        detachRenderbufferImpl(gl, Attachment.Type.DEPTH_STENCIL, false);
+    }
+    
+    private final void detachAllImpl(GL gl, boolean detachNonColorbuffer, boolean recreate) {
+        for(int i=0; i<maxColorAttachments; i++) {
+            detachColorbufferImpl(gl, i, recreate);
+        }
+        if( !recreate && colorAttachmentCount>0 ) {
+            throw new InternalError("Non zero ColorAttachments "+this);
+        }
+        
+        if(detachNonColorbuffer) {
+            detachRenderbufferImpl(gl, Attachment.Type.DEPTH_STENCIL, recreate);
+        }
+        
+        if(DEBUG) {
+            System.err.println("FBObject.detachAll: [resetNonColorbuffer "+detachNonColorbuffer+", recreate "+recreate+"]: "+this);
+        }
+    }
+        
+    /**
+     * @param gl the current GL context
+     */
+    public final void destroy(GL gl) {
+        if(null != samplesSink) {
+            samplesSink.destroy(gl);
+        }
+        
+        detachAllImpl(gl, true /* detachNonColorbuffer */, false /* recreate */);
+        
+        // cache FB names, preset exposed to zero,
+        // braking ties w/ GL/GLContext link to getReadFramebuffer()/getWriteFramebuffer()
+        final int fb_cache = fbName;
+        fbName = 0;
+
+        int name[] = new int[1];
+        if(0!=fb_cache) {
+            name[0] = fb_cache;
+            gl.glDeleteFramebuffers(1, name, 0);
+        }        
+        initialized = false;
+        bound = false;
+        if(DEBUG) {
+            System.err.println("FBObject.destroy: "+this);
+        }
+    }
+
+    private final boolean sampleSinkSizeMismatch() {
+        return samplesSink.getWidth() != width || samplesSink.getHeight() != height ;
+    }
+    private final boolean sampleSinkTexMismatch() {
+        return null == samplesSinkTexture || 0 == samplesSinkTexture.getName() ;
+    }
+    private final boolean sampleSinkDepthStencilMismatch() {
+        final boolean depthMismatch   = ( null != depth && null == samplesSink.depth ) ||
+                                        ( null != depth && null != samplesSink.depth &&
+                                          depth.format != samplesSink.depth.format );
+        
+        final boolean stencilMismatch = ( null != stencil && null == samplesSink.stencil ) ||
+                                        ( null != stencil && null != samplesSink.stencil &&
+                                          stencil.format != samplesSink.stencil.format );        
+        
+        return depthMismatch || stencilMismatch;                
+    }
+        
+    private final void resetMSAATexture2DSink(GL gl) throws GLException {
+        if(0 == samples) {
+            // MSAA off
+            if(null != samplesSink) {
+                samplesSink.detachAll(gl);
+            }
+            return;
+        }
+        
+        boolean sampleSinkSizeMismatch = sampleSinkSizeMismatch();
+        boolean sampleSinkTexMismatch = sampleSinkTexMismatch();
+        boolean sampleSinkDepthStencilMismatch = sampleSinkDepthStencilMismatch();
+        
+        /** if(DEBUG) {
+            System.err.println("FBObject.resetMSAATexture2DSink.0: \n\tTHIS "+this+",\n\tSINK "+samplesSink+
+                               "\n\t size "+sampleSinkSizeMismatch +", tex "+sampleSinkTexMismatch +", depthStencil "+sampleSinkDepthStencilMismatch);
+        } */
+        
+        if(!sampleSinkSizeMismatch && !sampleSinkTexMismatch && !sampleSinkDepthStencilMismatch) {
+            // all properties match .. 
+            return;            
+        }
+        
+        unbind(gl);
+        
+        if(DEBUG) {
+            System.err.println("FBObject.resetMSAATexture2DSink: BEGIN\n\tTHIS "+this+",\n\tSINK "+samplesSink+
+                               "\n\t size "+sampleSinkSizeMismatch +", tex "+sampleSinkTexMismatch +", depthStencil "+sampleSinkDepthStencilMismatch);
+        }
+                
+        if( sampleSinkDepthStencilMismatch ) {
+            samplesSink.detachAllRenderbuffer(gl);
+        }
+        
+        if( sampleSinkSizeMismatch ) {
+            samplesSink.reset(gl, width, height);
+        }
+        
+        if(null == samplesSinkTexture) {
+            samplesSinkTexture = samplesSink.attachTexture2D(gl, 0, true);
+        } else if( 0 == samplesSinkTexture.getName() ) {
+            samplesSinkTexture.setSize(width, height);
+            samplesSink.attachTexture2D(gl, 0, samplesSinkTexture);
+        }
+        
+        if( sampleSinkDepthStencilMismatch ) {
+            samplesSink.attachRenderbuffer(gl, depth.format);
+            if( null != stencil && !isDepthStencilPackedFormat() ) {
+                samplesSink.attachRenderbuffer(gl, stencil.format);
+            }
+        }        
+        
+        sampleSinkSizeMismatch = sampleSinkSizeMismatch();
+        sampleSinkTexMismatch = sampleSinkTexMismatch();
+        sampleSinkDepthStencilMismatch = sampleSinkDepthStencilMismatch();
+        if(sampleSinkSizeMismatch || sampleSinkTexMismatch || sampleSinkDepthStencilMismatch) {
+            throw new InternalError("Samples sink mismatch after reset: \n\tTHIS "+this+",\n\t SINK "+samplesSink+
+                                    "\n\t size "+sampleSinkSizeMismatch +", tex "+sampleSinkTexMismatch +", depthStencil "+sampleSinkDepthStencilMismatch);
+        }
+        
+        if(DEBUG) {
+            System.err.println("FBObject.resetMSAATexture2DSink: END\n\tTHIS "+this+",\n\tSINK "+samplesSink+
+                               "\n\t size "+sampleSinkSizeMismatch +", tex "+sampleSinkTexMismatch +", depthStencil "+sampleSinkDepthStencilMismatch);
+        }
+    }
+    
+    /** 
+     * Bind this FBO, i.e. bind write framebuffer to {@link #getWriteFramebuffer()}.
+     * 
+     * <p>If multisampling is used, it sets the read framebuffer to the sampling sink {@link #getWriteFramebuffer()}, 
+     * if full FBO is supported.</p>
+     *  
+     * <p> 
+     * In case you have attached more than one color buffer,
+     * you may want to setup {@link GL2GL3#glDrawBuffers(int, int[], int)}.
+     * </p>
+     * @param gl the current GL context
+     * @throws GLException
+     */
+    public final void bind(GL gl) throws GLException {
+        if(!bound || fbName != gl.getBoundFramebuffer(GL.GL_FRAMEBUFFER)) {
+            checkInitialized();
+            if(samples > 0 && fullFBOSupport) {
+                // draw to multisampling - read from samplesSink
+                gl.glBindFramebuffer(GL2GL3.GL_DRAW_FRAMEBUFFER, getWriteFramebuffer());
+                gl.glBindFramebuffer(GL2GL3.GL_READ_FRAMEBUFFER, getReadFramebuffer());
+            } else {
+                // one for all
+                gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, getWriteFramebuffer());                
+            }
+
+            checkNoError(null, gl.glGetError(), "FBObject post-bind"); // throws GLException if error
+            bound = true;
+            samplesSinkDirty = true;
+        }
+    }
+
+    /** 
+     * Unbind this FBO, i.e. bind read and write framebuffer to default, see {@link GLBase#getDefaultDrawFramebuffer()}.
+     * 
+     * <p>If full FBO is supported, sets the read and write framebuffer individually to default, hence not disturbing 
+     * an optional operating MSAA FBO, see {@link GLBase#getDefaultReadFramebuffer()} and {@link GLBase#getDefaultDrawFramebuffer()}</p>
+     *  
+     * @param gl the current GL context
+     * @throws GLException
+     */
+    public final void unbind(GL gl) throws GLException {
+        if(bound) {
+            if(fullFBOSupport) {
+                // default read/draw buffers, may utilize GLContext/GLDrawable override of 
+                // GLContext.getDefaultDrawFramebuffer() and GLContext.getDefaultReadFramebuffer()
+                gl.glBindFramebuffer(GL2GL3.GL_DRAW_FRAMEBUFFER, 0);
+                gl.glBindFramebuffer(GL2GL3.GL_READ_FRAMEBUFFER, 0);
+            } else {
+                gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, 0); // default draw buffer                
+            }
+            checkNoError(null, gl.glGetError(), "FBObject post-unbind"); // throws GLException if error
+            bound = false;
+        }
+    }
+
+    /** 
+     * Returns <code>true</code> if framebuffer object is bound via {@link #bind(GL)}, otherwise <code>false</code>.
+     * <p>
+     * Method verifies the bound state via {@link GL#getBoundFramebuffer(int)}.
+     * </p>
+     * @param gl the current GL context
+     */
+    public final boolean isBound(GL gl) { 
+        bound = bound &&  fbName != gl.getBoundFramebuffer(GL.GL_FRAMEBUFFER) ;
+        return bound;
+    }
+    
+    /** Returns <code>true</code> if framebuffer object is bound via {@link #bind(GL)}, otherwise <code>false</code>. */
+    public final boolean isBound() { return bound; }
+    
+    /** 
+     * Samples the multisampling colorbuffer (msaa-buffer) to it's sink {@link #getSamplingSink()}.
+     *
+     * <p>The operation is skipped, if no multisampling is used or 
+     * the msaa-buffer has not been flagged dirty by a previous call of {@link #bind(GL)},
+     * see {@link #isSamplingBufferDirty()} </p>
+     * 
+     * <p>If full FBO is supported, sets the read and write framebuffer individually to default after sampling, hence not disturbing 
+     * an optional operating MSAA FBO, see {@link GLBase#getDefaultReadFramebuffer()} and {@link GLBase#getDefaultDrawFramebuffer()}</p>
+     * 
+     * <p>In case you intend to employ {@link GL#glReadPixels(int, int, int, int, int, int, java.nio.Buffer) glReadPixels(..)}
+     * you may want to call {@link GL#glBindFramebuffer(int, int) glBindFramebuffer}({@link GL2GL3#GL_READ_FRAMEBUFFER}, {@link #getReadFramebuffer()});
+     * </p>
+     * 
+     * <p>Leaves the FBO unbound.</p>
+     * 
+     * @param gl the current GL context
+     * @param ta {@link TextureAttachment} to use, prev. attached w/  {@link #attachTexture2D(GL, int, boolean, int, int, int, int) attachTexture2D(..)}
+     * @throws IllegalArgumentException  
+     */
+    public final void syncSamplingBuffer(GL gl) {
+        unbind(gl);
+        if(samples>0 && samplesSinkDirty) {
+            samplesSinkDirty = false;
+            resetMSAATexture2DSink(gl);
+            gl.glBindFramebuffer(GL2GL3.GL_READ_FRAMEBUFFER, fbName);
+            gl.glBindFramebuffer(GL2GL3.GL_DRAW_FRAMEBUFFER, samplesSink.getWriteFramebuffer());
+            ((GL2GL3)gl).glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, // since MSAA is supported, ugly cast is OK
+                                           GL.GL_COLOR_BUFFER_BIT, GL.GL_NEAREST);
+            if(fullFBOSupport) {
+                // default read/draw buffers, may utilize GLContext/GLDrawable override of 
+                // GLContext.getDefaultDrawFramebuffer() and GLContext.getDefaultReadFramebuffer()
+                gl.glBindFramebuffer(GL2GL3.GL_DRAW_FRAMEBUFFER, 0);
+                gl.glBindFramebuffer(GL2GL3.GL_READ_FRAMEBUFFER, 0);
+            } else {
+                gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, 0); // default draw buffer                
+            }
+        }
+    }
+    
+    /** 
+     * Bind the given texture colorbuffer.
+     * 
+     * <p>If multisampling is being used, {@link #syncSamplingBuffer(GL)} is being called.</p>
+     *  
+     * <p>Leaves the FBO unbound!</p>
+     * 
+     * @param gl the current GL context
+     * @param ta {@link TextureAttachment} to use, prev. attached w/  {@link #attachTexture2D(GL, int, boolean, int, int, int, int) attachTexture2D(..)}
+     * @throws IllegalArgumentException  
+     */
+    public final void use(GL gl, TextureAttachment ta) throws IllegalArgumentException {
+        if(null == ta) { throw new IllegalArgumentException("null TextureAttachment"); }
+        if(samples > 0 && samplesSinkTexture == ta) {
+            syncSamplingBuffer(gl);
+        } else {
+            unbind(gl);            
+        }
+        gl.glBindTexture(GL.GL_TEXTURE_2D, ta.getName()); // use it ..
+    }
+
+    /** 
+     * Unbind texture, ie bind 'non' texture 0
+     *  
+     * <p>Leaves the FBO unbound.</p>
+     */    
+    public final void unuse(GL gl) {
+        unbind(gl);
+        gl.glBindTexture(GL.GL_TEXTURE_2D, 0); // don't use it
+    }
+
+    /** 
+     * Returns <code>true</code> if <i>basic</i> or <i>full</i> FBO is supported, otherwise <code>false</code>.
+     * @param full <code>true</code> for <i>full</i> FBO supported query, otherwise <code>false</code> for <i>basic</i> FBO support query.
+     * @see #supportsFullFBO(GL)
+     * @see #supportsBasicFBO(GL)
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final boolean supportsFBO(boolean full) throws GLException { checkInitialized(); return full ? fullFBOSupport : basicFBOSupport; }
+    
+    /** 
+     * Returns <code>true</code> if renderbuffer accepts internal format {@link GL#GL_RGB8} and {@link GL#GL_RGBA8}, otherwise <code>false</code>.
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final boolean supportsRGBA8() throws GLException { checkInitialized(); return rgba8Avail; }
+    
+    /** 
+     * Returns <code>true</code> if {@link GL#GL_DEPTH_COMPONENT16}, {@link GL#GL_DEPTH_COMPONENT24} or {@link GL#GL_DEPTH_COMPONENT32} is supported, otherwise <code>false</code>.
+     * @param bits 16, 24 or 32 bits
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final boolean supportsDepth(int bits) throws GLException {
+        checkInitialized();
+        switch(bits) {
+            case 16: return basicFBOSupport; 
+            case 24: return depth24Avail;
+            case 32: return depth32Avail;
+            default: return false;            
+        }
+    }
+    
+    /** 
+     * Returns <code>true</code> if {@link GL#GL_STENCIL_INDEX1}, {@link GL#GL_STENCIL_INDEX4}, {@link GL#GL_STENCIL_INDEX8} or {@link GL2GL3#GL_STENCIL_INDEX16} is supported, otherwise <code>false</code>.
+     * @param bits 1, 4, 8 or 16 bits
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final boolean supportsStencil(int bits) throws GLException {
+        checkInitialized();
+        switch(bits) {
+            case  1: return stencil01Avail; 
+            case  4: return stencil04Avail;
+            case  8: return stencil08Avail;
+            case 16: return stencil16Avail;
+            default: return false;            
+        }
+    }
+    
+    /** 
+     * Returns <code>true</code> if {@link GL#GL_DEPTH24_STENCIL8} is supported, otherwise <code>false</code>.
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final boolean supportsPackedDepthStencil() throws GLException { checkInitialized(); return packedDepthStencilAvail; }
+    
+    /**
+     * Returns the maximum number of colorbuffer attachments.
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final int getMaxColorAttachments() throws GLException { checkInitialized(); return maxColorAttachments; }
+    
+    /**
+     * Returns the maximum number of samples for multisampling. Maybe zero if multisampling is not supported. 
+     * @throws GLException if {@link #init(GL)} hasn't been called.
+     */
+    public final int getMaxSamples() throws GLException { checkInitialized(); return maxSamples; }
+    
+    /**
+     * Returns <code>true</code> if this instance has been initialized with {@link #reset(GL, int, int)} 
+     * or {@link #reset(GL, int, int, int)}, otherwise <code>false</code>
+     */
+    public final boolean isInitialized() { return initialized; }
+    /** Returns the width */
+    public final int getWidth() { return width; }
+    /** Returns the height */
+    public final int getHeight() { return height; }
+    /** Returns the number of samples for multisampling (MSAA). zero if no multisampling is used. */
+    public final int getNumSamples() { return samples; }
+    /** Returns the framebuffer name to render to. */
+    public final int getWriteFramebuffer() { return fbName; }
+    /** Returns the framebuffer name to read from. Depending on multisampling, this may be a different framebuffer. */
+    public final int getReadFramebuffer() { return ( samples > 0 ) ? samplesSink.getReadFramebuffer() : fbName; }
+    /** Return the number of color/texture attachments */
+    public final int getColorAttachmentCount() { return colorAttachmentCount; }
+    /** Return the stencil {@link RenderAttachment} attachment, if exist. Maybe share the same {@link Attachment#getName()} as {@link #getDepthAttachment()}, if packed depth-stencil is being used. */ 
+    public final RenderAttachment getStencilAttachment() { return stencil; }
+    /** Return the depth {@link RenderAttachment} attachment. Maybe share the same {@link Attachment#getName()} as {@link #getStencilAttachment()}, if packed depth-stencil is being used. */ 
+    public final RenderAttachment getDepthAttachment() { return depth; }
+    
+    /** Return the complete multisampling {@link FBObject} sink, if using multisampling. */ 
+    public final FBObject getSamplingSinkFBO() { return samplesSink; }
+    
+    /** Return the multisampling {@link TextureAttachment} sink, if using multisampling. */ 
+    public final TextureAttachment getSamplingSink() { return samplesSinkTexture; }
+    /** 
+     * Returns <code>true</code> if the multisampling colorbuffer (msaa-buffer) 
+     * has been flagged dirty by a previous call of {@link #bind(GL)},
+     * otherwise <code>false</code>.
+     */
+    public final boolean isSamplingBufferDirty() { return samplesSinkDirty; }
+    
+    int objectHashCode() { return super.hashCode(); }
+    
+    public final String toString() {
+        final String caps = null != colorAttachmentPoints ? Arrays.asList(colorAttachmentPoints).toString() : null ; 
+        return "FBO[name r/w "+fbName+"/"+getReadFramebuffer()+", init "+initialized+", bound "+bound+", size "+width+"x"+height+", samples "+samples+"/"+maxSamples+
+               ", depth "+depth+", stencil "+stencil+", color attachments: "+colorAttachmentCount+"/"+maxColorAttachments+
+               ": "+caps+", msaa-sink "+samplesSinkTexture+", isSamplesSink "+(null == samplesSink)+
+               ", obj 0x"+Integer.toHexString(objectHashCode())+"]";
+    }
+    
+    private final void updateStatus(GL gl) {
+        if( 0 == fbName ) {
+            vStatus = -1;
+        } else {
+            vStatus = gl.glCheckFramebufferStatus(GL.GL_FRAMEBUFFER);
+        }
+    }       
+}