From d143475e995e473c142fd34be2af6521246f014a Mon Sep 17 00:00:00 2001
From: Sven Gothel <sgothel@jausoft.com>
Date: Fri, 8 Mar 2013 22:58:34 +0100
Subject: GLJPanel: Updating GLJPanel documention w/ current mode of operation
---
.../classes/javax/media/opengl/awt/GLJPanel.java | 26 ++++++++++++----------
1 file changed, 14 insertions(+), 12 deletions(-)
(limited to 'src/jogl/classes/javax/media/opengl')
diff --git a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
index 5f9551610..8d9493cbf 100644
--- a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
+++ b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
@@ -104,18 +104,20 @@ import com.jogamp.opengl.util.GLPixelStorageModes;
#setOpaque}(false). Pixels with resulting OpenGL alpha values less
than 1.0 will be overlaid on any underlying Swing rendering. </P>
<P>
- Notes specific to the Reference Implementation: This component
- attempts to use hardware-accelerated rendering via pbuffers and
- falls back on to software rendering if problems occur.
- Note that because this component attempts to use pbuffers for
- rendering, and because pbuffers can not be resized, somewhat
- surprising behavior may occur during resize operations; the {@link
- GLEventListener#init} method may be called multiple times as the
- pbuffer is resized to be able to cover the size of the GLJPanel.
- This behavior is correct, as the textures and display lists for
- the GLJPanel will have been lost during the resize operation. The
- application should attempt to make its GLEventListener.init()
- methods as side-effect-free as possible. </P>
+ This component attempts to use hardware-accelerated rendering via FBO or pbuffers and
+ falls back on to software rendering if none of the former are available
+ using {@link GLDrawableFactory#createOffscreenDrawable(AbstractGraphicsDevice, GLCapabilitiesImmutable, GLCapabilitiesChooser, int, int) GLDrawableFactory.createOffscreenDrawable(..)}.<br/>
+ </P>
+ <P>
+ The OpenGL rendered pixels are copied to an {@link BufferedImage} via {@link GL#glReadPixels(int, int, int, int, int, int, java.nio.Buffer) glReadPixels(..)}
+ which is drawn to the Swing <i>space</i> via {@link Graphics#drawImage(java.awt.Image, int, int, int, int, java.awt.image.ImageObserver) Graphics.drawImage(...)}.
+ </p>
+ <P>
+ If FBO is being used and GLSL is available, a fragment shader is utilized
+ to flip the OpenGL pixels vertically before <code>glReadPixels(..)</code>,
+ if not disabled via system property <code>jogl.gljpanel.noglsl</code>.<br/>
+ Otherwise {@link System#arraycopy(Object, int, Object, int, int) System.arraycopy(..)} is used line by line, causing more CPU load per frame.
+ </P>
<P>
* Please read <A HREF="GLCanvas.html#java2dgl">Java2D OpenGL Remarks</A>.
* </P>
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