path: root/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PMSAAES2.java

/**
 * Copyright 2010-2023 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 jogamp.graph.curve.opengl;

import java.io.File;
import java.nio.FloatBuffer;

import com.jogamp.opengl.GL2ES2;
import com.jogamp.opengl.GLProfile;
import com.jogamp.opengl.GL;
import com.jogamp.opengl.GLUniformData;

import jogamp.graph.curve.opengl.shader.AttributeNames;
import jogamp.graph.curve.opengl.shader.UniformNames;

import com.jogamp.graph.curve.Region;
import com.jogamp.graph.curve.opengl.GLRegion;
import com.jogamp.graph.curve.opengl.RegionRenderer;
import com.jogamp.graph.curve.opengl.RenderState;
import com.jogamp.math.Matrix4f;
import com.jogamp.math.Recti;
import com.jogamp.math.geom.AABBox;
import com.jogamp.math.util.SyncMatrices4f16;
import com.jogamp.opengl.FBObject;
import com.jogamp.opengl.FBObject.Attachment;
import com.jogamp.opengl.FBObject.TextureAttachment;
import com.jogamp.opengl.util.GLArrayDataServer;
import com.jogamp.opengl.util.GLReadBufferUtil;
import com.jogamp.opengl.util.glsl.ShaderProgram;
import com.jogamp.opengl.util.texture.Texture;
import com.jogamp.opengl.util.texture.TextureSequence;

public final class VBORegion2PMSAAES2  extends GLRegion {
    private static final boolean DEBUG_FBO_1 = false;
    private static final boolean DEBUG_FBO_2 = false;
    private static final boolean SCREENSHOT_FBO = false;

    private final RenderState.ProgramLocal rsLocal;

    // Pass-1:
    private final GLUniformData gcu_ColorTexUnit;
    private final float[] colorTexBBox; // minX/minY, maxX/maxY, texW/texH
    private final GLUniformData gcu_ColorTexBBox; // vec2 gcu_ColorTexBBox[3] -> boxMin[2], boxMax[2] and texSize[2]
    private final float[] clipBBox; // minX/minY/minZ, maxX/maxY/maxZ
    private final GLUniformData gcu_ClipBBox; // uniform vec3  gcu_ClipBBox[2]; // box-min[3], box-max[3]
    private ShaderProgram spPass1 = null;

    // Pass-2:
    private GLArrayDataServer gca_FboVerticesAttr;
    private GLArrayDataServer gca_FboTexCoordsAttr;
    private GLArrayDataServer indicesFbo;
    private final GLUniformData gcu_FboTexUnit;
    private final Matrix4f matP = new Matrix4f();
    private final Matrix4f matMv = new Matrix4f();
    private final GLUniformData gcu_PMVMatrix02;
    private ShaderProgram spPass2 = null;

    private FBObject fbo;
    private TextureAttachment texA;
    private GLReadBufferUtil screenshot = SCREENSHOT_FBO ? new GLReadBufferUtil(true, false) : null;

    private int fboWidth = 0;
    private int fboHeight = 0;
    private boolean fboDirty = true;

    final int[] maxTexSize = new int[] { -1 } ;

    public VBORegion2PMSAAES2(final GLProfile glp, final int renderModes, final TextureSequence colorTexSeq, final int pass2TexUnit,
                              final int initialVerticesCount, final int initialIndicesCount)
    {
        super(glp, renderModes, colorTexSeq);

        rsLocal = new RenderState.ProgramLocal();

        // We leave GLArrayDataClient.DEFAULT_GROWTH_FACTOR intact for avg +19% size, but 15% less CPU overhead compared to 1.2 (19% total)

        // Pass 1:
        initBuffer(initialVerticesCount, initialIndicesCount);

        if( hasColorTexture() ) {
            gcu_ColorTexUnit = new GLUniformData(UniformNames.gcu_ColorTexUnit, colorTexSeq.getTextureUnit());
            colorTexBBox = new float[6];
            gcu_ColorTexBBox = new GLUniformData(UniformNames.gcu_ColorTexBBox, 2, FloatBuffer.wrap(colorTexBBox));
        } else {
            gcu_ColorTexUnit = null;
            colorTexBBox = null;
            gcu_ColorTexBBox = null;
        }
        clipBBox = new float[6];
        gcu_ClipBBox = new GLUniformData(UniformNames.gcu_ClipBBox, 3, FloatBuffer.wrap(clipBBox));
        gcu_PMVMatrix02 = new GLUniformData(UniformNames.gcu_PMVMatrix02, 4, 4, new SyncMatrices4f16( new Matrix4f[] { matP, matMv } ));

        // Pass 2:
        gcu_FboTexUnit = new GLUniformData(UniformNames.gcu_FboTexUnit, pass2TexUnit);

        indicesFbo = GLArrayDataServer.createData(3, GL.GL_UNSIGNED_SHORT, 2, GL.GL_STATIC_DRAW, GL.GL_ELEMENT_ARRAY_BUFFER);
        indicesFbo.puts((short) 0); indicesFbo.puts((short) 1); indicesFbo.puts((short) 3);
        indicesFbo.puts((short) 1); indicesFbo.puts((short) 2); indicesFbo.puts((short) 3);
        indicesFbo.seal(true);

        gca_FboTexCoordsAttr = GLArrayDataServer.createGLSL(AttributeNames.FBO_TEXCOORDS_ATTR_NAME, 2, GL.GL_FLOAT,
                                                           false, 4, GL.GL_STATIC_DRAW);
        gca_FboTexCoordsAttr.putf(0); gca_FboTexCoordsAttr.putf(0);
        gca_FboTexCoordsAttr.putf(0); gca_FboTexCoordsAttr.putf(1);
        gca_FboTexCoordsAttr.putf(1); gca_FboTexCoordsAttr.putf(1);
        gca_FboTexCoordsAttr.putf(1); gca_FboTexCoordsAttr.putf(0);
        gca_FboTexCoordsAttr.seal(true);

        gca_FboVerticesAttr = GLArrayDataServer.createGLSL(AttributeNames.FBO_VERTEX_ATTR_NAME, 3, GL.GL_FLOAT,
                                                           false, 4, GL.GL_STATIC_DRAW);
    }

    @Override
    public void setTextureUnit(final int pass2TexUnit) {
        gcu_FboTexUnit.setData(pass2TexUnit);
    }

    @Override
    protected final void clearImpl(final GL2ES2 gl) {
        fboDirty = true;
    }

    @Override
    protected void updateImpl(final GL2ES2 gl, final RegionRenderer renderer, final int curRenderModes) {
        // final boolean hasColorChannel = Region.hasColorChannel( curRenderModes );
        final boolean hasColorTexture = Region.hasColorTexture( curRenderModes );

        // seal buffers
        indicesBuffer.seal(gl, true);
        indicesBuffer.enableBuffer(gl, false);
        vpc_ileave.seal(gl, true);
        vpc_ileave.enableBuffer(gl, false);
        if( hasColorTexture && null != gcu_ColorTexUnit && colorTexSeq.isTextureAvailable() ) {
            TextureSequence.setTexCoordBBox(colorTexSeq.getLastTexture().getTexture(), box, isColorTextureLetterbox(), colorTexBBox, false);
        }
        // Pending gca_FboVerticesAttr-seal and fboPMVMatrix-setup, follow fboDirty

        // push data 2 GPU ..
        indicesFbo.seal(gl, true);
        indicesFbo.enableBuffer(gl, false);

        fboDirty = true;
        // the buffers were disabled, since due to real/fbo switching and other vbo usage
    }

    /**
     * <p>
     * Since multiple {@link Region}s may share one
     * {@link ShaderProgram} managed and owned by {@link RegionRendered}, the uniform data must always be updated.
     * </p>
     *
     * @param gl
     * @param renderer
     * @param renderModes
     * @param pass1
     * @param pass2Quality
     * @param sampleCount
     */
    public void useShaderProgram(final GL2ES2 gl, final RegionRenderer renderer, final int curRenderModes, final boolean pass1, final int pass2Quality, final int sampleCount) {
        final boolean isTwoPass = Region.isTwoPass( curRenderModes );
        final boolean hasColorChannel = Region.hasColorChannel( curRenderModes );
        final boolean hasColorTexture = Region.hasColorTexture( curRenderModes ) && null != colorTexSeq;

        final RenderState rs = renderer.getRenderState();
        final boolean hasAABBoxClipping = null != rs.getClipBBox() && ( ( !isTwoPass && pass1 ) || ( isTwoPass && !pass1 ) );

        final boolean updateLocGlobal = renderer.useShaderProgram(gl, curRenderModes, pass1, pass2Quality, sampleCount, colorTexSeq);
        final ShaderProgram sp = renderer.getRenderState().getShaderProgram();
        final boolean updateLocLocal;
        if( pass1 ) {
            updateLocLocal = !sp.equals(spPass1);
            spPass1 = sp;
            if( DEBUG ) {
                if( DEBUG_ALL_EVENT || updateLocLocal || updateLocGlobal ) {
                    System.err.println("XXX changedSP.p1 updateLocation loc "+updateLocLocal+" / glob "+updateLocGlobal+", sp "+sp.program()+" / "+sp.id());
                }
            }
            if( updateLocLocal ) {
                rs.updateAttributeLoc(gl, true, gca_VerticesAttr, true);
                rs.updateAttributeLoc(gl, true, gca_CurveParamsAttr, true);
                if( hasColorChannel && null != gca_ColorsAttr ) {
                    rs.updateAttributeLoc(gl, true, gca_ColorsAttr, true);
                }
            }
            if( isTwoPass ) {
                rsLocal.update(gl, rs, updateLocLocal, curRenderModes, false, true, true);
                rs.updateUniformLoc(gl, updateLocLocal, gcu_PMVMatrix02, true);
            } else {
                rsLocal.update(gl, rs, updateLocLocal, curRenderModes, true, true, true);
            }
            if( hasColorTexture && null != gcu_ColorTexUnit ) {
                rs.updateUniformLoc(gl, updateLocLocal, gcu_ColorTexUnit, true);
                rs.updateUniformLoc(gl, updateLocLocal, gcu_ColorTexBBox, true);
            }
        } else {
            updateLocLocal = !sp.equals(spPass2);
            spPass2 = sp;
            if( DEBUG ) {
                if( DEBUG_ALL_EVENT || updateLocLocal || updateLocGlobal ) {
                    System.err.println("XXX changedSP.p2 updateLocation loc "+updateLocLocal+" / glob "+updateLocGlobal+", sp "+sp.program()+" / "+sp.id());
                }
            }
            if( updateLocLocal ) {
                rs.updateAttributeLoc(gl, true, gca_FboVerticesAttr, true);
                rs.updateAttributeLoc(gl, true, gca_FboTexCoordsAttr, true);
            }
            rsLocal.update(gl, rs, updateLocLocal, curRenderModes, true, false, true);
            rs.updateUniformDataLoc(gl, updateLocLocal, false /* updateData */, gcu_FboTexUnit, true); // FIXME always update if changing tex-unit
        }
        if( hasAABBoxClipping && updateLocLocal ) {
            rs.updateUniformLoc(gl, true, gcu_ClipBBox, true);
        }
    }

    private final AABBox drawWinBox = new AABBox();
    private final Recti drawView = new Recti();

    private static final int border = 2; // surrounding border, i.e. width += 2*border, height +=2*border

    @Override
    protected void drawImpl(final GL2ES2 gl, final RegionRenderer renderer, final int curRenderModes, final int pass2Quality, final int[/*1*/] sampleCount) {
        if( 0 >= indicesBuffer.getElemCount() ) {
            if(DEBUG_INSTANCE) {
                System.err.printf("VBORegion2PMSAAES2.drawImpl: Empty%n");
            }
            return; // empty!
        }
        if( Float.isInfinite(box.getWidth()) || Float.isInfinite(box.getHeight()) ) {
            if(DEBUG_INSTANCE) {
                System.err.printf("VBORegion2PMSAAES2.drawImpl: Inf %s%n", box);
            }
            return; // inf
        }
        final RenderState rs = renderer.getRenderState();
        final int vpWidth = renderer.getWidth();
        final int vpHeight = renderer.getHeight();
        if(vpWidth <=0 || vpHeight <= 0 || sampleCount[0] < 0) {
            useShaderProgram(gl, renderer, curRenderModes, true, pass2Quality, sampleCount[0]);
            renderRegion(gl, rs, curRenderModes);
        } else {
            if(0 > maxTexSize[0]) {
                gl.glGetIntegerv(GL.GL_MAX_TEXTURE_SIZE, maxTexSize, 0);
            }
            final float winWidth, winHeight;

            final float ratioObjWinWidth, ratioObjWinHeight;
            final float diffObjWidth, diffObjHeight;
            final float diffObjBorderWidth, diffObjBorderHeight;
            int targetFboWidth, targetFboHeight;
            {
                final float diffWinWidth, diffWinHeight;
                final int targetWinWidth, targetWinHeight;

                // Calculate perspective pixel width/height for FBO,
                // considering the sampleCount.
                drawView.setWidth(vpWidth);
                drawView.setHeight(vpHeight);

                box.mapToWindow(drawWinBox, renderer.getMatrix().getPMv(), drawView, true /* useCenterZ */);

                winWidth = drawWinBox.getWidth();
                winHeight = drawWinBox.getHeight();
                targetWinWidth = (int)Math.ceil(winWidth);
                targetWinHeight = (int)Math.ceil(winHeight);
                diffWinWidth = targetWinWidth-winWidth;
                diffWinHeight = targetWinHeight-winHeight;

                ratioObjWinWidth = box.getWidth() / winWidth;
                ratioObjWinHeight= box.getHeight() / winHeight;
                diffObjWidth = diffWinWidth * ratioObjWinWidth;
                diffObjHeight = diffWinHeight * ratioObjWinHeight;
                diffObjBorderWidth = border * ratioObjWinWidth;
                diffObjBorderHeight = border * ratioObjWinHeight;

                targetFboWidth = targetWinWidth+2*border;
                targetFboHeight = targetWinHeight+2*border;

                if( DEBUG_FBO_2 ) {
                    final float ratioWinWidth, ratioWinHeight;
                    ratioWinWidth = winWidth/targetWinWidth;
                    ratioWinHeight = winHeight/targetWinHeight;

                    System.err.printf("XXX.MinMax obj %s%n", box.toString());
                    System.err.printf("XXX.MinMax obj d[%.3f, %.3f], r[%f, %f], b[%f, %f]%n",
                            diffObjWidth, diffObjHeight, ratioObjWinWidth, ratioObjWinWidth, diffObjBorderWidth, diffObjBorderHeight);
                    System.err.printf("XXX.MinMax win %s%n", drawWinBox.toString());
                    System.err.printf("XXX.MinMax view[%s] -> win[%.3f, %.3f], i[%d x %d], d[%.3f, %.3f], r[%f, %f]: FBO i[%d x %d], samples %d%n",
                            drawView,
                            winWidth, winHeight, targetWinWidth, targetWinHeight,
                            diffWinWidth, diffWinHeight, ratioWinWidth, ratioWinHeight,
                            targetFboWidth, targetFboHeight,
                            sampleCount[0]);
                }
            }
            if( 0 >= targetFboWidth || 0 >= targetFboHeight ) {
                // Nothing ..
                return;
            }
            final int deltaFboWidth = Math.abs(targetFboWidth-fboWidth);
            final int deltaFboHeight = Math.abs(targetFboHeight-fboHeight);
            final boolean hasDelta = 0!=deltaFboWidth || 0!=deltaFboHeight;
            if( DEBUG_FBO_2 ) {
                System.err.printf("XXX.maxDelta: hasDelta %b: %d / %d,  %.3f, %.3f%n",
                        hasDelta, deltaFboWidth, deltaFboHeight, (float)deltaFboWidth/fboWidth, (float)deltaFboHeight/fboHeight);
                System.err.printf("XXX.Scale %d * [%f x %f]: %d x %d%n",
                        sampleCount[0], winWidth, winHeight, targetFboWidth, targetFboHeight);
            }
            if( hasDelta || fboDirty || isShapeDirty() || null == fbo ) {
                // FIXME: rescale
                final float minX = box.getMinX()-diffObjBorderWidth;
                final float minY = box.getMinY()-diffObjBorderHeight;
                final float maxX = box.getMaxX()+diffObjBorderWidth+diffObjWidth;
                final float maxY = box.getMaxY()+diffObjBorderHeight+diffObjHeight;
                final float minZ = box.getMinZ();
                gca_FboVerticesAttr.seal(false);
                {
                    final FloatBuffer fb = (FloatBuffer)gca_FboVerticesAttr.getBuffer();
                    fb.put(0, minX); fb.put( 1, minY); fb.put( 2, minZ);
                    fb.put(3, minX); fb.put( 4, maxY); fb.put( 5, minZ);
                    fb.put(6, maxX); fb.put( 7, maxY); fb.put( 8, minZ);
                    fb.put(9, maxX); fb.put(10, minY); fb.put(11, minZ);
                    fb.position(12);
                }
                gca_FboVerticesAttr.seal(true);
                matP.setToOrtho(minX, maxX, minY, maxY, -1, 1);
                useShaderProgram(gl, renderer, curRenderModes, true, pass2Quality, sampleCount[0]);
                renderRegion2FBO(gl, rs, curRenderModes,
                                 // (int)drawWinBox.getMinX(), (int)drawWinBox.getMinY(), targetFboWidth, targetFboHeight,
                                 0, 0, targetFboWidth, targetFboHeight,
                                 vpWidth, vpHeight, sampleCount);
            } else if( isStateDirty() ) {
                useShaderProgram(gl, renderer, curRenderModes, true, pass2Quality, sampleCount[0]);
                renderRegion2FBO(gl, rs, curRenderModes,
                                 // (int)drawWinBox.getMinX(), (int)drawWinBox.getMinY(), targetFboWidth, targetFboHeight,
                                 0, 0, targetFboWidth, targetFboHeight,
                                 vpWidth, vpHeight, sampleCount);
            }
            useShaderProgram(gl, renderer, curRenderModes, false, pass2Quality, sampleCount[0]);
            renderFBO(gl, rs, vpWidth, vpHeight, sampleCount[0]);
        }
    }

    private void renderFBO(final GL2ES2 gl, final RenderState rs, final int width, final int height, final int sampleCount) {
        gl.glViewport(0, 0, width, height);

        if( rs.isHintMaskSet(RenderState.BITHINT_BLENDING_ENABLED | RenderState.BITHINT_GLOBAL_DEPTH_TEST_ENABLED) ) {
            // BITHINT_GLOBAL_DEPTH_TEST_ENABLED path added by commit 45395696c252c215a8a22d05e5da7e98c662d07e (2014-04-10),
            // but not in VBORegion2PVBAA.renderVBO(..) -> investigate if required for working MSAA:
            // - "VBORegion2PMSAAES2 enables/disables GL_DEPTH_TEST, otherwise MSAA is corrupt"
            //
            // RGB is already multiplied w/ alpha via renderRegion2FBO(..)
            gl.glBlendFunc(GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA);
            gl.glEnable(GL.GL_DEPTH_TEST);

        } else if( rs.isHintMaskSet(RenderState.BITHINT_BLENDING_ENABLED) ) {
            // RGB is already multiplied w/ alpha via renderRegion2FBO(..)
            gl.glBlendFunc(GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA);
        }

        {
            final AABBox cb = rs.getClipBBox();
            if( null != cb ) {
                clipBBox[0] = cb.getMinX(); clipBBox[1] = cb.getMinY(); clipBBox[2] = cb.getMinZ();
                clipBBox[3] = cb.getMaxX(); clipBBox[4] = cb.getMaxY(); clipBBox[5] = cb.getMaxZ();
                gl.glUniform(gcu_ClipBBox); // Always update, since program maybe used by multiple regions
            }
        }

        gl.glActiveTexture(GL.GL_TEXTURE0 + gcu_FboTexUnit.intValue());

        fbo.use(gl, texA);
        gca_FboVerticesAttr.enableBuffer(gl, true);
        gca_FboTexCoordsAttr.enableBuffer(gl, true);
        indicesFbo.bindBuffer(gl, true); // keeps VBO binding

        gl.glDrawElements(GL.GL_TRIANGLES, indicesFbo.getElemCount() * indicesFbo.getCompsPerElem(), GL.GL_UNSIGNED_SHORT, 0);

        indicesFbo.bindBuffer(gl, false);
        gca_FboTexCoordsAttr.enableBuffer(gl, false);
        gca_FboVerticesAttr.enableBuffer(gl, false);
        fbo.unuse(gl);

        // setback: gl.glActiveTexture(currentActiveTextureEngine[0]);
    }

    private void renderRegion2FBO(final GL2ES2 gl, final RenderState rs, final int curRenderModes,
                                  final int fboX, final int fboY, final int targetFboWidth, final int targetFboHeight,
                                  final int vpWidth, final int vpHeight, final int[] sampleCount) {
        if( 0 >= targetFboWidth || 0 >= targetFboHeight ) {
            throw new IllegalArgumentException("targetFBOSize "+targetFboWidth+"x"+targetFboHeight+" must be greater than 0");
        }
        final boolean blendingEnabled = rs.isHintMaskSet(RenderState.BITHINT_BLENDING_ENABLED);
        final int targetFboSamples = sampleCount[0] > 1 ? sampleCount[0] : 0;
        final boolean fboSampleTypeMatch;
        {
            final int oldSampleCount = null != fbo ? fbo.getNumSamples() : 0;
            fboSampleTypeMatch = ( oldSampleCount > 1 && targetFboSamples > 1 ) || ( oldSampleCount <= 1 && targetFboSamples <= 1 );
        }

        if(null == fbo || !fboSampleTypeMatch) {
            if( null != fbo ) {
                fbo.destroy(gl);
            }
            fboWidth  = targetFboWidth;
            fboHeight  = targetFboHeight;
            fbo = new FBObject();
            fbo.init(gl, targetFboWidth, targetFboHeight, targetFboSamples);
            sampleCount[0] = Math.max(1, fbo.getNumSamples());
            if( 0 == targetFboSamples ) {
                texA = fbo.attachTexture2D(gl, 0, true, GL.GL_LINEAR, GL.GL_LINEAR, GL.GL_CLAMP_TO_EDGE, GL.GL_CLAMP_TO_EDGE);
                if( !blendingEnabled ) {
                    // no depth-buffer w/ blending
                    fbo.attachRenderbuffer(gl, Attachment.Type.DEPTH, FBObject.DEFAULT_BITS);
                }
            } else {
                fbo.attachColorbuffer(gl, 0, true);
                if( !blendingEnabled ) {
                    // no depth-buffer w/ blending
                    fbo.attachRenderbuffer(gl, Attachment.Type.DEPTH, FBObject.DEFAULT_BITS);
                }
                final FBObject ssink = new FBObject();
                {
                    ssink.init(gl, targetFboWidth, targetFboHeight, 0);
                    texA = ssink.attachTexture2D(gl, 0, true, GL.GL_NEAREST, GL.GL_NEAREST, GL.GL_CLAMP_TO_EDGE, GL.GL_CLAMP_TO_EDGE);
                    if( !blendingEnabled ) {
                        // no depth-buffer w/ blending
                        ssink.attachRenderbuffer(gl, Attachment.Type.DEPTH, FBObject.DEFAULT_BITS);
                    }
                }
                fbo.setSamplingSink(ssink);
                fbo.resetSamplingSink(gl); // validate
            }
            if( DEBUG_FBO_1 ) {
                System.err.printf("XXX.createFBO: blending %b, %dx%d%n%s%n", blendingEnabled, targetFboWidth, targetFboHeight, fbo.toString());
            }
        } else if( targetFboWidth != fboWidth || targetFboHeight != fboHeight || fbo.getNumSamples() != targetFboSamples ) {
            fbo.reset(gl, targetFboWidth, targetFboHeight, targetFboSamples);
            sampleCount[0] = Math.max(1, fbo.getNumSamples());
            if( DEBUG_FBO_1 ) {
                System.err.printf("XXX.resetFBO: %dx%d -> %dx%d%n%s%n", fboWidth, fboHeight, targetFboWidth, targetFboHeight, fbo );
            }
            fboWidth  = targetFboWidth;
            fboHeight  = targetFboHeight;
        }
        fbo.bind(gl);

        //render texture
        gl.glViewport(fboX, fboY, targetFboWidth, targetFboHeight);
        if( blendingEnabled ) {
            gl.glClearColor(0f, 0f, 0f, 0.0f);
            gl.glClear(GL.GL_COLOR_BUFFER_BIT); // no depth-buffer w/ blending
            // For already pre-multiplied alpha values, use:
            // gl.glBlendFunc(GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA);

            // Multiply RGB w/ Alpha, preserve alpha for renderFBO(..)
            gl.glBlendFuncSeparate(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA, GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA);

            if( rs.isHintMaskSet(RenderState.BITHINT_GLOBAL_DEPTH_TEST_ENABLED) ) {
                gl.glDisable(GL.GL_DEPTH_TEST);
            }
        } else {
            gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        }

        renderRegion(gl, rs, curRenderModes);

        if( SCREENSHOT_FBO ) {
            screenshot.setReadBuffer(GL.GL_COLOR_ATTACHMENT0);
            if(screenshot.readPixels(gl, fboX, fboY, targetFboWidth, targetFboHeight, false)) {
                final File f = new File("screenshot_vboregion2pmsaa.png");
                screenshot.write(f);
            }
        }

        fbo.unbind(gl);
        fboDirty = false;
    }

    private void renderRegion(final GL2ES2 gl, final RenderState rs, final int curRenderModes) {
        // final boolean hasColorChannel = Region.hasColorChannel( curRenderModes );
        final boolean hasColorTexture = Region.hasColorTexture( curRenderModes );

        gl.glUniform(gcu_PMVMatrix02);

        vpc_ileave.enableBuffer(gl, true);
        indicesBuffer.bindBuffer(gl, true); // keeps VBO binding
        if( hasColorTexture && null != gcu_ColorTexUnit && colorTexSeq.isTextureAvailable() ) {
            final TextureSequence.TextureFrame frame = colorTexSeq.getNextTexture(gl);
            gl.glActiveTexture(GL.GL_TEXTURE0 + colorTexSeq.getTextureUnit());
            final Texture tex = frame.getTexture();
            tex.bind(gl);
            tex.enable(gl); // nop on core
            gcu_ColorTexUnit.setData(colorTexSeq.getTextureUnit());
            gl.glUniform(gcu_ColorTexUnit); // Always update, since program maybe used by multiple regions
            gl.glUniform(gcu_ColorTexBBox); // Always update, since program maybe used by multiple regions
            gl.glDrawElements(GL.GL_TRIANGLES, indicesBuffer.getElemCount() * indicesBuffer.getCompsPerElem(), glIdxType(), 0);
            tex.disable(gl); // nop on core
        } else {
            gl.glDrawElements(GL.GL_TRIANGLES, indicesBuffer.getElemCount() * indicesBuffer.getCompsPerElem(), glIdxType(), 0);
        }

        indicesBuffer.bindBuffer(gl, false);
        vpc_ileave.enableBuffer(gl, false);
    }

    @Override
    protected void destroyImpl(final GL2ES2 gl) {
        if(DEBUG_INSTANCE) {
            System.err.println("VBORegion2PES2 Destroy: " + this);
        }
        if(null != fbo) {
            fbo.destroy(gl);
            fbo = null;
            texA = null;
        }
        if(null != gca_FboVerticesAttr) {
            gca_FboVerticesAttr.destroy(gl);
            gca_FboVerticesAttr = null;
        }
        if(null != gca_FboTexCoordsAttr) {
            gca_FboTexCoordsAttr.destroy(gl);
            gca_FboTexCoordsAttr = null;
        }
        if(null != indicesFbo) {
            indicesFbo.destroy(gl);
            indicesFbo = null;
        }
        if( null != screenshot ) {
            screenshot.dispose(gl);
            screenshot = null;
        }
        spPass1 = null; // owned by RegionRenderer
        spPass2 = null; // owned by RegionRenderer
    }
}