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-rw-r--r--src/jogl/classes/javax/media/opengl/awt/GLJPanel.java21
1 files changed, 11 insertions, 10 deletions
diff --git a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
index 40fc1001f..a5142aa98 100644
--- a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
+++ b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
@@ -130,19 +130,19 @@ import com.jogamp.opengl.util.texture.TextureState;
using {@link GLDrawableFactory#createOffscreenDrawable(AbstractGraphicsDevice, GLCapabilitiesImmutable, GLCapabilitiesChooser, int, int) GLDrawableFactory.createOffscreenDrawable(..)}.<br/>
</p>
<p>
- <a name="verticalFlip">
- In case</a> the drawable {@link #isGLOriented()} and {@link #setSkipGLOrientationVerticalFlip(boolean) vertical flip is not skipped},
- this component performs the required vertical flip to bring the content from OpenGL's orientation into AWT's orientation.
+ <a name="verticalFlip">A vertical-flip is required</a>, if the drawable {@link #isGLOriented()} and {@link #setSkipGLOrientationVerticalFlip(boolean) vertical flip is not skipped}.<br>
+ In this case this component performs the required vertical flip to bring the content from OpenGL's orientation into AWT's orientation.<br>
+ In case <a href="#fboGLSLVerticalFlip">GLSL based vertical-flip</a> is not available,
+ the CPU intensive {@link System#arraycopy(Object, int, Object, int, int) System.arraycopy(..)} is used line by line.
See details about <a href="#fboGLSLVerticalFlip">FBO and GLSL vertical flipping</a>.
</p>
<p>
- The OpenGL path is concluded by copying the rendered pixels an {@link BufferedImage} via {@link GL#glReadPixels(int, int, int, int, int, int, java.nio.Buffer) glReadPixels(..)}
- for later Java2D composition.
+ For performance reasons, as well as for <a href="#bug842">GL state sideeffects</a>,
+ <b>{@link #setSkipGLOrientationVerticalFlip(boolean) skipping vertical flip} is highly recommended</b>!
</p>
<p>
- In case {@link #setSkipGLOrientationVerticalFlip(boolean) vertical-flip is not skipped} and <a href="#fboGLSLVerticalFlip">GLSL based vertical-flip</a> is not performed,
- {@link System#arraycopy(Object, int, Object, int, int) System.arraycopy(..)} is used line by line.
- This step causes more CPU load per frame and is not hardware-accelerated.
+ The OpenGL path is concluded by copying the rendered pixels an {@link BufferedImage} via {@link GL#glReadPixels(int, int, int, int, int, int, java.nio.Buffer) glReadPixels(..)}
+ for later Java2D composition.
</p>
<p>
Finally the Java2D compositioning takes place via via {@link Graphics#drawImage(java.awt.Image, int, int, int, int, java.awt.image.ImageObserver) Graphics.drawImage(...)}
@@ -153,7 +153,8 @@ import com.jogamp.opengl.util.texture.TextureState;
* </P>
*
<a name="fboGLSLVerticalFlip"><h5>FBO / GLSL Vertical Flip</h5></a>
- In case FBO is used and GLSL is available and {@link #setSkipGLOrientationVerticalFlip(boolean) vertical flip is not skipped}, a fragment shader is utilized
+ If <a href="#verticalFlip">vertical flip is required</a>,
+ FBO is used, GLSL is available and {@link #setSkipGLOrientationVerticalFlip(boolean) vertical flip is not skipped}, a fragment shader is utilized
to flip the FBO texture vertically. This hardware-accelerated step can be disabled via system property <code>jogl.gljpanel.noglsl</code>.
<p>
The FBO / GLSL code path uses one texture-unit and binds the FBO texture to it's active texture-target,
@@ -167,7 +168,7 @@ import com.jogamp.opengl.util.texture.TextureState;
The current gl-viewport is preserved.
</p>
<p>
- <i>Warning (Bug 842)</i>: Certain GL states other than viewport and texture (see above)
+ <a name="bug842"><i>Warning (Bug 842)</i></a>: Certain GL states other than viewport and texture (see above)
influencing rendering, will also influence the GLSL vertical flip, e.g. {@link GL#glFrontFace(int) glFrontFace}({@link GL#GL_CCW}).
It is recommended to reset those states to default when leaving the {@link GLEventListener#display(GLAutoDrawable)} method!
We may change this behavior in the future, i.e. preserve all influencing states.