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

15 files changed, 30 insertions, 62 deletions

diff --git a/doc/userguide/index.html b/doc/userguide/index.html
index 06d047f3f..58b8b3e29 100644
--- a/doc/userguide/index.html
+++ b/doc/userguide/index.html
@@ -159,6 +159,18 @@ recommendation when it is available, and otherwise attempts to use a
 platform-independent selection algorithm.
 
 </P>
+<P>
+
+The GLJPanel can be made non-opaque according to Swing's rendering
+model, so it can act as an overlay to other Swing or Java2D drawing.
+In order to enable this, set up your GLCapabilities object with a
+non-zero alpha depth (a common value is 8 bits) and call
+setOpaque(false) on the GLJPanel once it has been created. Java2D
+rendering underneath it will then show through areas where OpenGL has
+produced an alpha value less than 1.0. See the JGears and JRefract
+demos for examples of how to use this functionality.
+
+</P>
 
 <H2> Writing a GLEventListener </H2>
 
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,
diff --git a/src/net/java/games/jogl/impl/GLContext.java b/src/net/java/games/jogl/impl/GLContext.java
index a70b195ac..41fa98c4b 100644
--- a/src/net/java/games/jogl/impl/GLContext.java
+++ b/src/net/java/games/jogl/impl/GLContext.java
@@ -593,10 +593,6 @@ public abstract class GLContext {
       requests. */
   protected abstract boolean isOffscreen();
 
-  /** Only called for offscreen contexts; returns the type of
-      BufferedImage required for reading this context's pixels. */
-  public abstract int getOffscreenContextBufferedImageType();
-
   /** Only called for offscreen contexts; returns the buffer from
       which to read pixels (GL.GL_FRONT or GL.GL_BACK). */
   public abstract int getOffscreenContextReadBuffer();
diff --git a/src/net/java/games/jogl/impl/macosx/MacOSXDummyGLContext.java b/src/net/java/games/jogl/impl/macosx/MacOSXDummyGLContext.java
index 9361ab5c0..29a3ef63b 100644
--- a/src/net/java/games/jogl/impl/macosx/MacOSXDummyGLContext.java
+++ b/src/net/java/games/jogl/impl/macosx/MacOSXDummyGLContext.java
@@ -66,10 +66,6 @@ class MacOSXDummyGLContext extends MacOSXGLContext
     return false;
   }
 	
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-	
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/macosx/MacOSXGLContext.java b/src/net/java/games/jogl/impl/macosx/MacOSXGLContext.java
index 272f72372..ec58de9a6 100644
--- a/src/net/java/games/jogl/impl/macosx/MacOSXGLContext.java
+++ b/src/net/java/games/jogl/impl/macosx/MacOSXGLContext.java
@@ -93,10 +93,6 @@ public abstract class MacOSXGLContext extends GLContext
   
   protected abstract boolean isOffscreen();
 	
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/macosx/MacOSXOffscreenGLContext.java b/src/net/java/games/jogl/impl/macosx/MacOSXOffscreenGLContext.java
index 1cb3269e2..37b2302c0 100644
--- a/src/net/java/games/jogl/impl/macosx/MacOSXOffscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/macosx/MacOSXOffscreenGLContext.java
@@ -59,10 +59,6 @@ public class MacOSXOffscreenGLContext extends MacOSXPbufferGLContext
     return true;
   }
   
-  public int getOffscreenContextBufferedImageType() {
-      return BufferedImage.TYPE_INT_ARGB;
-  }
-	
   public int getOffscreenContextWidth() {
       return initWidth;
   }
diff --git a/src/net/java/games/jogl/impl/macosx/MacOSXOnscreenGLContext.java b/src/net/java/games/jogl/impl/macosx/MacOSXOnscreenGLContext.java
index 7b6337c8e..ba4eee0ef 100644
--- a/src/net/java/games/jogl/impl/macosx/MacOSXOnscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/macosx/MacOSXOnscreenGLContext.java
@@ -70,10 +70,6 @@ public class MacOSXOnscreenGLContext extends MacOSXGLContext {
     return false;
   }
     
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-    
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/windows/WindowsGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
index f597d56b7..e838c68aa 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
@@ -106,8 +106,6 @@ public abstract class WindowsGLContext extends GLContext {
 
   protected abstract boolean isOffscreen();
   
-  public abstract int getOffscreenContextBufferedImageType();
-
   public int getOffscreenContextWidth() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/windows/WindowsOffscreenGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsOffscreenGLContext.java
index dbb6fc69c..c70607da7 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsOffscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsOffscreenGLContext.java
@@ -65,14 +65,6 @@ public class WindowsOffscreenGLContext extends WindowsGLContext {
     return true;
   }
 
-  public int getOffscreenContextBufferedImageType() {
-    if (capabilities.getAlphaBits() > 0) {
-      return BufferedImage.TYPE_INT_ARGB;
-    } else {
-      return BufferedImage.TYPE_INT_RGB;
-    }
-  }
-
   public int getOffscreenContextWidth() {
       return width;
   }
diff --git a/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
index d66412e74..0dc1818fb 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
@@ -89,10 +89,6 @@ public class WindowsOnscreenGLContext extends WindowsGLContext {
     return false;
   }
   
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/windows/WindowsPbufferGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsPbufferGLContext.java
index 077a852c9..1d5d78296 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsPbufferGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsPbufferGLContext.java
@@ -455,10 +455,6 @@ public class WindowsPbufferGLContext extends WindowsGLContext {
     return false;
   }
 
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/x11/X11GLContext.java b/src/net/java/games/jogl/impl/x11/X11GLContext.java
index 13018764a..53f44101f 100644
--- a/src/net/java/games/jogl/impl/x11/X11GLContext.java
+++ b/src/net/java/games/jogl/impl/x11/X11GLContext.java
@@ -110,8 +110,6 @@ public abstract class X11GLContext extends GLContext {
 
   protected abstract boolean isOffscreen();
   
-  public abstract int getOffscreenContextBufferedImageType();
-
   public int getOffscreenContextWidth() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/x11/X11OffscreenGLContext.java b/src/net/java/games/jogl/impl/x11/X11OffscreenGLContext.java
index aeabe8afb..8f0aa06a5 100644
--- a/src/net/java/games/jogl/impl/x11/X11OffscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/x11/X11OffscreenGLContext.java
@@ -65,14 +65,6 @@ public class X11OffscreenGLContext extends X11GLContext {
     return true;
   }
 
-  public int getOffscreenContextBufferedImageType() {
-    if (capabilities.getAlphaBits() > 0) {
-      return BufferedImage.TYPE_INT_ARGB;
-    } else {
-      return BufferedImage.TYPE_INT_RGB;
-    }
-  }
-
   public int getOffscreenContextWidth() {
       return width;
   }
diff --git a/src/net/java/games/jogl/impl/x11/X11OnscreenGLContext.java b/src/net/java/games/jogl/impl/x11/X11OnscreenGLContext.java
index c79501017..2fd340d79 100644
--- a/src/net/java/games/jogl/impl/x11/X11OnscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/x11/X11OnscreenGLContext.java
@@ -70,10 +70,6 @@ public class X11OnscreenGLContext extends X11GLContext {
     return false;
   }
   
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }
diff --git a/src/net/java/games/jogl/impl/x11/X11PbufferGLContext.java b/src/net/java/games/jogl/impl/x11/X11PbufferGLContext.java
index a5a1785a2..d9f18a760 100644
--- a/src/net/java/games/jogl/impl/x11/X11PbufferGLContext.java
+++ b/src/net/java/games/jogl/impl/x11/X11PbufferGLContext.java
@@ -286,10 +286,6 @@ public class X11PbufferGLContext extends X11GLContext {
     return false;
   }
 
-  public int getOffscreenContextBufferedImageType() {
-    throw new GLException("Should not call this");
-  }
-
   public int getOffscreenContextReadBuffer() {
     throw new GLException("Should not call this");
   }