Bug 801: Refine 'blend' usage and modes (API-doc and demo-code)

- RegionRenderer: Make 'blend' setup pluggable via new GLCallbacks
  - 'GLCallback's for enable/disable, passed via 'create' method.
    Add 'defaultBlendEnable' and 'defaultBlendDisable',
    replacing previos fixed calls.

- GLRegion.draw(..) added API-doc notes about:
  - Decorating call with RegionRenderer.enable(..)
  - glClearColor impact and blending

- VBORegion2P*: Remove fixed glClearColor(..) call

3 files changed, 2 insertions, 4 deletions

diff --git a/src/jogl/classes/jogamp/graph/curve/opengl/RegionRendererImpl01.java b/src/jogl/classes/jogamp/graph/curve/opengl/RegionRendererImpl01.java
index c2762591a..e50caa663 100644
--- a/src/jogl/classes/jogamp/graph/curve/opengl/RegionRendererImpl01.java
+++ b/src/jogl/classes/jogamp/graph/curve/opengl/RegionRendererImpl01.java
@@ -41,8 +41,8 @@ import com.jogamp.opengl.util.glsl.ShaderState;
 
 public class RegionRendererImpl01 extends RegionRenderer {
 
-    public RegionRendererImpl01(RenderState rs, int renderModes) {
-        super(rs, renderModes);
+    public RegionRendererImpl01(final RenderState rs, final int renderModes, final GLCallback enableCallback, final GLCallback disableCallback) {
+        super(rs, renderModes, enableCallback, disableCallback);
     }
 
     @Override
diff --git a/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PMSAAES2.java b/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PMSAAES2.java
index 9b15ba319..4d653af12 100644
--- a/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PMSAAES2.java
+++ b/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PMSAAES2.java
@@ -353,7 +353,6 @@ public class VBORegion2PMSAAES2  extends GLRegion {
         gl.glViewport(0, 0, fboWidth, fboHeight);
         st.uniform(gl, mgl_fboPMVMatrix); // use orthogonal matrix
 
-        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
         gl.glClear(GL2ES2.GL_COLOR_BUFFER_BIT | GL2ES2.GL_DEPTH_BUFFER_BIT);
         renderRegion(gl);
         fbo.unbind(gl);
diff --git a/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PVBAAES2.java b/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PVBAAES2.java
index cac39fb21..07a774d51 100644
--- a/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PVBAAES2.java
+++ b/src/jogl/classes/jogamp/graph/curve/opengl/VBORegion2PVBAAES2.java
@@ -349,7 +349,6 @@ public class VBORegion2PVBAAES2  extends GLRegion {
         gl.glViewport(0, 0, fboWidth, fboHeight);
         st.uniform(gl, mgl_fboPMVMatrix); // use orthogonal matrix
 
-        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
         gl.glClear(GL2ES2.GL_COLOR_BUFFER_BIT | GL2ES2.GL_DEPTH_BUFFER_BIT);
         renderRegion(gl);
         fbo.unbind(gl);