Adding unit test for Bug 605 - WORKSFORME, i.e. no unwanted y-flip, so I can just assume it's the SW renderer, flipping.

3 files changed, 393 insertions, 27 deletions

diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageAWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageAWT.java
new file mode 100644
index 000000000..b949bc34d
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageAWT.java
@@ -0,0 +1,185 @@
+/**
+ * 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.test.junit.jogl.caps;
+
+import java.io.File;
+import java.io.IOException;
+
+import javax.media.opengl.GL;
+import javax.media.opengl.GL2;
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLDrawableFactory;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLException;
+import javax.media.opengl.GLProfile;
+
+import com.jogamp.opengl.util.awt.Screenshot;
+import com.jogamp.opengl.util.texture.TextureIO;
+
+import java.awt.image.BufferedImage;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+import com.jogamp.opengl.test.junit.util.UITestCase;
+
+public class TestBug605FlippedImageAWT extends UITestCase {
+    class FlippedImageTest implements GLEventListener {
+        public void display(GLAutoDrawable drawable) {
+            GL2 gl = drawable.getGL().getGL2();
+            
+            gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT | GL.GL_STENCIL_BUFFER_BIT | GL2.GL_ACCUM_BUFFER_BIT );
+            
+            gl.glMatrixMode(GL2.GL_PROJECTION);
+            gl.glLoadIdentity();
+            gl.glMatrixMode(GL2.GL_MODELVIEW);
+            gl.glLoadIdentity();
+    
+            // red below
+            gl.glColor3f(1, 0, 0);
+            gl.glRectf(-1, -1, 1, 0);
+    
+            // green above
+            gl.glColor3f(0, 1, 0);
+            gl.glRectf(-1, 0, 1, 1);
+            gl.glFinish();
+
+            final GLCapabilitiesImmutable caps = drawable.getChosenGLCapabilities();
+            if(caps.getAccumGreenBits() > 0) {
+                gl.glAccum(GL2.GL_ACCUM, 1.0f);
+                gl.glAccum(GL2.GL_RETURN, 1.0f);
+            }    
+            gl.glFinish();
+            
+            final int width = drawable.getWidth();
+            final int height = drawable.getHeight();
+            
+            final String fname = getSnapshotFilename(0, null, caps, width, height, false, TextureIO.PNG, null);
+            try {
+                Screenshot.writeToFile(new File(fname), width, height, false);
+            } catch (GLException e) {
+                throw e;
+            } catch (IOException e) {
+                throw new GLException(e);
+            }            
+            testFlipped(width, height);
+        }
+    
+        public void init(GLAutoDrawable drawable) {
+            final GL gl = drawable.getGL();
+            System.err.println("GL_RENDERER: "+gl.glGetString(GL.GL_RENDERER));
+            System.err.println("GL_VERSION: "+gl.glGetString(GL.GL_VERSION));
+        }    
+        public void reshape(GLAutoDrawable glDrawable, int x, int y, int w, int h) {}    
+        public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {}    
+        public void dispose(GLAutoDrawable drawable) {}
+    }
+    
+    static final int green = 0x0000ff00; // above
+    static final int red   = 0x00ff0000; // below
+
+    private void testFlipped(int width, int height) {
+        // Default origin 0/0 is lower left corner, so is the memory layout
+        // However AWT origin 0/0 is upper left corner 
+        final BufferedImage image = Screenshot.readToBufferedImage(width, height);
+        
+        final int below = image.getRGB(0, height-1) & 0x00ffffff;
+        System.err.println("below: 0x"+Integer.toHexString(below));
+        
+        final int above = image.getRGB(0, 0) & 0x00ffffff;
+        System.err.println("above: 0x"+Integer.toHexString(above));
+        
+        if (above == green && below == red) {
+            System.out.println("Image right side up");
+        } else if (above == red && below == green) {
+            Assert.assertTrue("Image is flipped", false);
+        } else {
+            Assert.assertTrue("Error in test", false);
+        }        
+    }
+    
+    private void test(GLCapabilitiesImmutable caps) {
+        
+        final GLDrawableFactory glFactory = GLDrawableFactory.getFactory(caps.getGLProfile());
+        final GLAutoDrawable glad = glFactory.createOffscreenAutoDrawable(null, caps, null, 256, 256, null);
+        final FlippedImageTest tglel = new FlippedImageTest();
+        glad.addGLEventListener(tglel);
+        
+        // 1 frame incl. snapshot to memory & file
+        glad.display();
+        System.err.println("XXX "+glad.getChosenGLCapabilities());
+        System.err.println("XXX "+glad.getContext().getGLVersion());
+                            
+        glad.destroy();        
+    }
+    
+    @Test
+    public void test01DefaultFBO() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setFBO(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01StencilFBO() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setStencilBits(8);
+        caps.setFBO(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01DefaultPBuffer() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setPBuffer(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01AccumStencilPBuffer() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setAccumRedBits(16);
+        caps.setAccumGreenBits(16);
+        caps.setAccumBlueBits(16);
+        caps.setStencilBits(8);
+        caps.setPBuffer(true);        
+        test(caps);        
+    }
+    
+    public static void main(String[] args) {
+        org.junit.runner.JUnitCore.main(TestBug605FlippedImageAWT.class.getName());
+    }
+}
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageNEWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageNEWT.java
new file mode 100644
index 000000000..837d94cb3
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/caps/TestBug605FlippedImageNEWT.java
@@ -0,0 +1,176 @@
+/**
+ * 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.test.junit.jogl.caps;
+
+import java.nio.ByteBuffer;
+
+import javax.media.opengl.GL;
+import javax.media.opengl.GL2;
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLDrawableFactory;
+import javax.media.opengl.GLEventListener;
+import javax.media.opengl.GLProfile;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+import com.jogamp.opengl.test.junit.util.UITestCase;
+import com.jogamp.opengl.util.GLReadBufferUtil;
+
+public class TestBug605FlippedImageNEWT extends UITestCase {
+    static class FlippedImageTest implements GLEventListener {
+        public void display(GLAutoDrawable drawable) {
+            GL2 gl = drawable.getGL().getGL2();
+            
+            gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT | GL.GL_STENCIL_BUFFER_BIT | GL2.GL_ACCUM_BUFFER_BIT );
+            
+            gl.glMatrixMode(GL2.GL_PROJECTION);
+            gl.glLoadIdentity();
+            gl.glMatrixMode(GL2.GL_MODELVIEW);
+            gl.glLoadIdentity();
+    
+            // red below
+            gl.glColor3f(1, 0, 0);
+            gl.glRectf(-1, -1, 1, 0);
+    
+            // green above
+            gl.glColor3f(0, 1, 0);
+            gl.glRectf(-1, 0, 1, 1);
+            gl.glFinish();
+    
+            final GLCapabilitiesImmutable caps = drawable.getChosenGLCapabilities();
+            if(caps.getAccumGreenBits() > 0) {
+                gl.glAccum(GL2.GL_ACCUM, 1.0f);
+                gl.glAccum(GL2.GL_RETURN, 1.0f);
+            }    
+            gl.glFinish();
+        }
+    
+        public void init(GLAutoDrawable drawable) {
+            final GL gl = drawable.getGL();
+            System.err.println("GL_RENDERER: "+gl.glGetString(GL.GL_RENDERER));
+            System.err.println("GL_VERSION: "+gl.glGetString(GL.GL_VERSION));
+        }    
+        public void reshape(GLAutoDrawable glDrawable, int x, int y, int w, int h) {}    
+        public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {}    
+        public void dispose(GLAutoDrawable drawable) {}
+    }
+    
+    static final int green = 0x0000ff00; // above
+    static final int red   = 0x00ff0000; // below
+
+    private int getRGB(ByteBuffer bb, int o) {
+        return ( (int)bb.get(o+0) & 0x000000ff ) << 16 | 
+               ( (int)bb.get(o+1) & 0x000000ff ) << 8 | 
+               ( (int)bb.get(o+2) & 0x000000ff );
+    }
+    
+    private void testFlipped(ByteBuffer bb, int width, int height, int comp) {
+        // Default origin 0/0 is lower left corner, so is the memory layout
+        
+        // x=0, y=0: RGB -> _RGB [high-byte .. low-byte]
+        final int below = getRGB(bb, 0);
+        System.err.println("below: 0x"+Integer.toHexString(below));
+        
+        // x=0, y=height-1: RGB -> _RGB [high-byte .. low-byte]
+        final int above= getRGB(bb, ( height - 1 ) * ( width * comp ));
+        System.err.println("above: 0x"+Integer.toHexString(above));
+        
+        if (above == green && below == red) {
+            System.out.println("Image right side up");
+        } else if (above == red && below == green) {
+            Assert.assertTrue("Image is flipped", false);
+        } else {
+            Assert.assertTrue("Error in test", false);
+        }        
+    }
+    
+    private void test(GLCapabilitiesImmutable caps) {
+        final GLReadBufferUtil rbu = new GLReadBufferUtil(false, false);
+        final GLDrawableFactory glFactory = GLDrawableFactory.getFactory(caps.getGLProfile());
+        final GLAutoDrawable glad = glFactory.createOffscreenAutoDrawable(null, caps, null, 256, 256, null);
+        final FlippedImageTest tglel = new FlippedImageTest();
+        glad.addGLEventListener(tglel);
+        final SnapshotGLEventListener snap = new SnapshotGLEventListener(rbu);
+        glad.addGLEventListener(snap);
+        snap.setMakeSnapshotAlways(true);        
+        
+        // 1 frame incl. snapshot to memory & file
+        glad.display();
+        System.err.println("XXX "+glad.getChosenGLCapabilities());
+        System.err.println("XXX "+glad.getContext().getGLVersion());
+        testFlipped(rbu.getPixelBuffer(), glad.getWidth(), glad.getHeight(), 3);        
+        
+        glad.destroy();        
+    }
+    
+    @Test
+    public void test01DefaultFBO() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setFBO(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01StencilFBO() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setStencilBits(8);
+        caps.setFBO(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01DefaultPBuffer() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setPBuffer(true);        
+        test(caps);        
+    }
+    
+    @Test
+    public void test01AccumStencilPBuffer() {
+        final GLProfile glp = GLProfile.get(GLProfile.GL2);
+        final GLCapabilities caps = new GLCapabilities(glp);
+        caps.setAccumRedBits(16);
+        caps.setAccumGreenBits(16);
+        caps.setAccumBlueBits(16);
+        caps.setStencilBits(8);
+        caps.setPBuffer(true);        
+        test(caps);        
+    }
+    
+    public static void main(String[] args) {
+        org.junit.runner.JUnitCore.main(TestBug605FlippedImageNEWT.class.getName());
+    }
+}
diff --git a/src/test/com/jogamp/opengl/test/junit/util/UITestCase.java b/src/test/com/jogamp/opengl/test/junit/util/UITestCase.java
index b48f027bb..bd9cd0966 100644
--- a/src/test/com/jogamp/opengl/test/junit/util/UITestCase.java
+++ b/src/test/com/jogamp/opengl/test/junit/util/UITestCase.java
@@ -142,25 +142,8 @@ public abstract class UITestCase {
     }
     
     static final String unsupportedTestMsg = "Test not supported on this platform.";
-    
-    /**
-     * Takes a snapshot of the drawable's current front framebuffer. Example filenames: 
-     * <pre>
-     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testES2OffScreenFBOSglBuf____-n0001-msaa0-GLES2_-sw-fbobject-Bdbl-Frgb__Irgb_-S00_default-0400x0300.png
-     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testES2OffScreenPbufferDblBuf-n0003-msaa0-GLES2_-sw-pbuffer_-Bdbl-Frgb__Irgb_-S00_default-0200x0150.png
-     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testGL2OffScreenPbufferSglBuf-n0003-msaa0-GL2___-hw-pbuffer_-Bone-Frgb__Irgb_-S00_default-0200x0150.png
-     * </pre>
-     * @param sn sequential number 
-     * @param postSNDetail optional detail to be added to the filename after <code>sn</code>
-     * @param gl the current GL context object. It's read drawable is being used as the pixel source and to gather some details which will end up in the filename.
-     * @param readBufferUtil the {@link GLReadBufferUtil} to be used to read the pixels for the screenshot.
-     * @param fileSuffix Optional file suffix without a <i>dot</i> defining the file type, i.e. <code>"png"</code>.
-     *                   If <code>null</code> the <code>"png"</code> as defined in {@link TextureIO#PNG} is being used.
-     * @param destPath Optional platform dependent file path. It shall use {@link File#separatorChar} as is directory separator.
-     *                 It shall not end with a directory separator, {@link File#separatorChar}.
-     *                 If <code>null</code> the current working directory is being used.  
-     */
-    public void snapshot(int sn, String postSNDetail, GL gl, GLReadBufferUtil readBufferUtil, String fileSuffix, String destPath) {
+
+    public String getSnapshotFilename(int sn, String postSNDetail, GLCapabilitiesImmutable caps, int width, int height, boolean sinkHasAlpha, String fileSuffix, String destPath) {
         if(null == fileSuffix) {
             fileSuffix = TextureIO.PNG;
         }
@@ -168,8 +151,6 @@ public abstract class UITestCase {
         final String simpleTestName = this.getSimpleTestName(".");
         final String filenameBaseName;
         {            
-            final GLDrawable drawable = gl.getContext().getGLReadDrawable();
-            final GLCapabilitiesImmutable caps = drawable.getChosenGLCapabilities();
             final String accel = caps.getHardwareAccelerated() ? "hw" : "sw" ;
             final String scrnm;
             if(caps.isOnscreen()) {
@@ -184,7 +165,7 @@ public abstract class UITestCase {
                 scrnm = "unknown_";
             }
             final String dblb = caps.getDoubleBuffered() ? "dbl" : "one";
-            final String F_pfmt = readBufferUtil.hasAlpha() ? "rgba" : "rgb_";
+            final String F_pfmt = sinkHasAlpha ? "rgba" : "rgb_";
             final String pfmt = caps.getAlphaBits() > 0 ? "rgba" : "rgb_";
             final int depthBits = caps.getDepthBits();
             final int stencilBits = caps.getStencilBits();
@@ -193,12 +174,36 @@ public abstract class UITestCase {
             postSNDetail = null != postSNDetail ? "-"+postSNDetail : "";
 
             filenameBaseName = String.format("%-"+maxSimpleTestNameLen+"s-n%04d%s-%-6s-%s-%s-B%s-F%s_I%s-D%02d-St%02d-Sa%02d_%s-%04dx%04d.%s", 
-                    simpleTestName, sn, postSNDetail, drawable.getGLProfile().getName(), accel, 
+                    simpleTestName, sn, postSNDetail, caps.getGLProfile().getName(), accel, 
                     scrnm, dblb, F_pfmt, pfmt, depthBits, stencilBits, samples, aaext,  
-                    drawable.getWidth(), drawable.getHeight(), fileSuffix).replace(' ', '_');
+                    width, height, fileSuffix).replace(' ', '_');
         }
-        final String filename = null != destPath ? destPath + File.separator + filenameBaseName : filenameBaseName;
-        System.err.println(Thread.currentThread().getName()+": ** screenshot: "+filename+", maxTestNameLen "+maxSimpleTestNameLen+", <"+simpleTestName+">");
+        return null != destPath ? destPath + File.separator + filenameBaseName : filenameBaseName;        
+    }
+    
+    /**
+     * Takes a snapshot of the drawable's current front framebuffer. Example filenames: 
+     * <pre>
+     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testES2OffScreenFBOSglBuf____-n0001-msaa0-GLES2_-sw-fbobject-Bdbl-Frgb__Irgb_-D24-St00-Sa00_default-0400x0300.png
+     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testES2OffScreenPbufferDblBuf-n0003-msaa0-GLES2_-sw-pbuffer_-Bdbl-Frgb__Irgb_-D24-St00-Sa00_default-0200x0150.png
+     * TestGLDrawableAutoDelegateOnOffscrnCapsNEWT.testGL2OffScreenPbufferSglBuf-n0003-msaa0-GL2___-hw-pbuffer_-Bone-Frgb__Irgb_-D24-St00-Sa00_default-0200x0150.png
+     * </pre>
+     * @param sn sequential number 
+     * @param postSNDetail optional detail to be added to the filename after <code>sn</code>
+     * @param gl the current GL context object. It's read drawable is being used as the pixel source and to gather some details which will end up in the filename.
+     * @param readBufferUtil the {@link GLReadBufferUtil} to be used to read the pixels for the screenshot.
+     * @param fileSuffix Optional file suffix without a <i>dot</i> defining the file type, i.e. <code>"png"</code>.
+     *                   If <code>null</code> the <code>"png"</code> as defined in {@link TextureIO#PNG} is being used.
+     * @param destPath Optional platform dependent file path. It shall use {@link File#separatorChar} as is directory separator.
+     *                 It shall not end with a directory separator, {@link File#separatorChar}.
+     *                 If <code>null</code> the current working directory is being used.  
+     */
+    public void snapshot(int sn, String postSNDetail, GL gl, GLReadBufferUtil readBufferUtil, String fileSuffix, String destPath) {
+        final GLDrawable drawable = gl.getContext().getGLReadDrawable();
+        final String filename = getSnapshotFilename(sn, postSNDetail, 
+                                                    drawable.getChosenGLCapabilities(), drawable.getWidth(), drawable.getHeight(), 
+                                                    readBufferUtil.hasAlpha(), fileSuffix, destPath);
+        System.err.println(Thread.currentThread().getName()+": ** screenshot: "+filename);
         gl.glFinish(); // just make sure rendering finished ..
         if(readBufferUtil.readPixels(gl, false)) {
             readBufferUtil.write(new File(filename));
@@ -219,7 +224,7 @@ public abstract class UITestCase {
         }
         public int getDisplayCount() { return displayCount; }
         public int getReshapeCount() { return reshapeCount; }
-
+        public GLReadBufferUtil getGLReadBufferUtil() { return screenshot; }
         public void init(GLAutoDrawable drawable) {}
         public void dispose(GLAutoDrawable drawable) {}
         public void display(GLAutoDrawable drawable) {