GLContextImpl/GLDrawableImpl.getDefaultReadBuffer(..): Pass hint whether dedicated read-drawable is being used (double buffering)

3 files changed, 6 insertions, 4 deletions

diff --git a/src/jogl/classes/jogamp/opengl/GLContextImpl.java b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
index b133fc017..9ccd78589 100644
--- a/src/jogl/classes/jogamp/opengl/GLContextImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
@@ -2231,7 +2231,7 @@ public abstract class GLContextImpl extends GLContext {
   @Override
   public final int getDefaultReadFramebuffer() { return drawable.getDefaultReadFramebuffer(); }
   @Override
-  public final int getDefaultReadBuffer() { return drawable.getDefaultReadBuffer(gl); }
+  public final int getDefaultReadBuffer() { return drawable.getDefaultReadBuffer(gl, drawableRead != drawable); }
 
   //---------------------------------------------------------------------------
   // GL_ARB_debug_output, GL_AMD_debug_output helpers
diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java b/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
index 94d39a4ab..d11274560 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
@@ -260,8 +260,8 @@ public abstract class GLDrawableImpl implements GLDrawable {
   /** Callback for special implementations, allowing GLContext to fetch a custom default read framebuffer. Defaults to zero. */
   protected int getDefaultReadFramebuffer() { return 0; }
   /** Callback for special implementations, allowing GLContext to fetch a custom default read buffer of current framebuffer. */
-  protected int getDefaultReadBuffer(GL gl) {
-      if(gl.isGLES() || getChosenGLCapabilities().getDoubleBuffered()) {
+  protected int getDefaultReadBuffer(GL gl, boolean hasDedicatedDrawableRead) {
+      if( gl.isGLES() || hasDedicatedDrawableRead || getChosenGLCapabilities().getDoubleBuffered() ) {
           // Note-1: Neither ES1 nor ES2 supports selecting the read buffer via glReadBuffer
           // Note-2: ES3 only supports GL_BACK, GL_NONE or GL_COLOR_ATTACHMENT0+i
           return GL.GL_BACK;
diff --git a/src/jogl/classes/jogamp/opengl/GLFBODrawableImpl.java b/src/jogl/classes/jogamp/opengl/GLFBODrawableImpl.java
index 0e9d142ba..6f5fa3eed 100644
--- a/src/jogl/classes/jogamp/opengl/GLFBODrawableImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLFBODrawableImpl.java
@@ -325,7 +325,9 @@ public class GLFBODrawableImpl extends GLDrawableImpl implements GLFBODrawable {
     protected final int getDefaultReadFramebuffer() { return initialized ? fbos[fboIFront].getReadFramebuffer() : 0; }
 
     @Override
-    protected final int getDefaultReadBuffer(GL gl) { return initialized ? fbos[fboIFront].getDefaultReadBuffer() : GL.GL_COLOR_ATTACHMENT0 ; }
+    protected final int getDefaultReadBuffer(GL gl, boolean hasDedicatedDrawableRead) {
+        return initialized ? fbos[fboIFront].getDefaultReadBuffer() : GL.GL_COLOR_ATTACHMENT0 ;
+    }
 
     @Override
     protected final void setRealizedImpl() {