Fixed Issue 168: Add support for transparency in GLJPanel

Obey setOpaque() when selecting buffered image type. User must still
request alpha bits in the GLCapabilities. Not supported on all
back-end renderers; for example, Microsoft GDI renderer does not
implement alpha bits when rendering to DIB sections. Added examples of
use in JGears and JRefract demos.


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/jogl/trunk@314 232f8b59-042b-4e1e-8c03-345bb8c30851

1 files changed, 18 insertions, 6 deletions

diff --git a/src/net/java/games/jogl/GLJPanel.java b/src/net/java/games/jogl/GLJPanel.java
index 59b2ee86d..e9b58bdae 100644
--- a/src/net/java/games/jogl/GLJPanel.java
+++ b/src/net/java/games/jogl/GLJPanel.java
@@ -310,6 +310,16 @@ public final class GLJPanel extends JPanel implements GLDrawable {
     }
   }
 
+  public void setOpaque(boolean opaque) {
+    if (opaque != isOpaque()) {
+      if (offscreenImage != null) {
+        offscreenImage.flush();
+        offscreenImage = null;
+      }
+    }
+    super.setOpaque(opaque);
+  }
+
   public void addGLEventListener(GLEventListener listener) {
     drawableHelper.addGLEventListener(listener);
   }
@@ -546,15 +556,17 @@ public final class GLJPanel extends JPanel implements GLDrawable {
           int awtFormat = 0;
           int hwGLFormat = 0;
           if (!hardwareAccelerationDisabled) {
-            // Should be more flexible in these BufferedImage formats;
-            // perhaps see what the preferred image types are on the
-            // given platform
-            awtFormat = BufferedImage.TYPE_INT_RGB;
-
             // This seems to be a good choice on all platforms
             hwGLFormat = GL.GL_UNSIGNED_INT_8_8_8_8_REV;
+          }
+
+          // Should be more flexible in these BufferedImage formats;
+          // perhaps see what the preferred image types are on the
+          // given platform
+          if (isOpaque()) {
+            awtFormat = BufferedImage.TYPE_INT_RGB;
           } else {
-            awtFormat = offscreenContext.getOffscreenContextBufferedImageType();
+            awtFormat = BufferedImage.TYPE_INT_ARGB;
           }
 
           offscreenImage = new BufferedImage(panelWidth,