From 5d0c40061b11909253f07b347db0342b1be38c80 Mon Sep 17 00:00:00 2001
From: Sven Gothel <sgothel@jausoft.com>
Date: Mon, 5 Oct 2015 08:24:43 +0200
Subject: Bug 1206 - Security: Clear exposed framebuffer after creation and
before visibility
Experimenting w/ no GLEventListener attached to an GLAutoDrawable,
e.g. GLWindow (onscreen), GLJPanel (fbo offscreen),
indeed on some GL implementations the default framebuffer is uninitialized
and hence shows garbage.
GLDrawableHelper.setViewportAndClear(..)
- Clear framebuffer after setting viewport
- Called from:
- public final void init(..)
- public final void reshape(..)
- Method is used independent of GLEventListener,
hence this simplifies implementation: removes 'setViewport' criteria
for init, display, reshape: it is always performed!
Note: We only attempt to help against leaking un-initialized framebuffer content
not against user-app faults, we do not clear a 2nd-buffer (double-buffering).
Note: We may still be late at resize, i.e. small noisy flickering might be visible.
This might be due to lack of proper vsync.
---
.../classes/jogamp/opengl/GLDrawableHelper.java | 64 +++++++++++-----------
1 file changed, 33 insertions(+), 31 deletions(-)
(limited to 'src/jogl/classes/jogamp/opengl/GLDrawableHelper.java')
diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
index 6bc93bf36..e4b5eae5c 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
@@ -76,6 +76,8 @@ public class GLDrawableHelper {
}
protected static final boolean DEBUG = GLDrawableImpl.DEBUG;
+ private static final boolean DEBUG_SETCLEAR = GLContext.DEBUG_GL || DEBUG;
+
private final Object listenersLock = new Object();
private final ArrayList<GLEventListener> listeners = new ArrayList<GLEventListener>();
private final HashSet<GLEventListener> listenersToBeInit = new HashSet<GLEventListener>();
@@ -638,10 +640,10 @@ public class GLDrawableHelper {
}
}
- private final void init(final GLEventListener l, final GLAutoDrawable drawable, final boolean sendReshape, final boolean setViewport) {
+ private final void init(final GLEventListener l, final GLAutoDrawable drawable, final boolean sendReshape) {
l.init(drawable);
if(sendReshape) {
- reshape(l, drawable, 0, 0, drawable.getSurfaceWidth(), drawable.getSurfaceHeight(), setViewport, false /* checkInit */);
+ l.reshape(drawable, 0, 0, drawable.getSurfaceWidth(), drawable.getSurfaceHeight());
}
}
@@ -650,6 +652,7 @@ public class GLDrawableHelper {
* @param sendReshape set to true if the subsequent display call won't reshape, otherwise false to avoid double reshape.
**/
public final void init(final GLAutoDrawable drawable, final boolean sendReshape) {
+ setViewportAndClear(drawable, 0, 0, drawable.getSurfaceWidth(), drawable.getSurfaceHeight());
synchronized(listenersLock) {
final ArrayList<GLEventListener> _listeners = listeners;
final int listenerCount = _listeners.size();
@@ -661,11 +664,8 @@ public class GLDrawableHelper {
// This may happen not just for initial setup, but for ctx recreation due to resource change (drawable/window),
// hence it must be called unconditional, always.
listenersToBeInit.remove(listener); // remove if exist, avoiding dbl init
- init( listener, drawable, sendReshape, 0==i /* setViewport */);
+ init(listener, drawable, sendReshape);
}
- } else {
- // Expose same GL initialization if not using any GLEventListener
- drawable.getGL().glViewport(0, 0, drawable.getSurfaceWidth(), drawable.getSurfaceHeight());
}
}
}
@@ -687,7 +687,7 @@ public class GLDrawableHelper {
// GLEventListener may need to be init,
// in case this one is added after the realization of the GLAutoDrawable
if( listenersToBeInit.remove(listener) ) {
- init( listener, drawable, true /* sendReshape */, listenersToBeInit.size() + 1 == listenerCount /* setViewport if 1st init */ );
+ init( listener, drawable, true /* sendReshape */ );
}
listener.display(drawable);
}
@@ -712,41 +712,43 @@ public class GLDrawableHelper {
// GLEventListener may need to be init,
// in case this one is added after the realization of the GLAutoDrawable
if( listenersToBeInit.remove(listener) ) {
- init( listener, drawable, true /* sendReshape */, listenersToBeInit.size() + 1 == listenerCount /* setViewport if 1st init */ );
+ init( listener, drawable, true /* sendReshape */ );
}
action.run(drawable, listener);
}
}
}
- private final void reshape(final GLEventListener listener, final GLAutoDrawable drawable,
- final int x, final int y, final int width, final int height, final boolean setViewport, final boolean checkInit) {
- if(checkInit) {
- // GLEventListener may need to be init,
- // in case this one is added after the realization of the GLAutoDrawable
- synchronized(listenersLock) {
- if( listenersToBeInit.remove(listener) ) {
- listener.init(drawable);
- }
- }
- }
- if(setViewport) {
- if( GLContext.DEBUG_GL || DEBUG ) {
- final int glerr0 = drawable.getGL().glGetError();
- if( GL.GL_NO_ERROR != glerr0 ) {
- System.err.println("Info: GLDrawableHelper.reshape: pre-exisiting GL error 0x"+Integer.toHexString(glerr0));
- ExceptionUtils.dumpStack(System.err);
- }
- }
- drawable.getGL().glViewport(x, y, width, height);
- }
- listener.reshape(drawable, x, y, width, height);
+ /**
+ * Bug 1206: Security: Clear exposed framebuffer after creation and before visibility
+ * - Clear framebuffer after setting viewport
+ * - Since we only attempt to help against leaking un-initialized framebuffer content
+ * not against user-app faults, we do not clear a 2nd-buffer (double-buffering).
+ */
+ private final void setViewportAndClear(final GLAutoDrawable drawable, final int x, final int y, final int width, final int height) {
+ final GL gl = drawable.getGL();
+ if( DEBUG_SETCLEAR ) {
+ final int glerr0 = gl.glGetError();
+ if( GL.GL_NO_ERROR != glerr0 ) {
+ System.err.println("Info: GLDrawableHelper.reshape: pre-exisiting GL error 0x"+Integer.toHexString(glerr0));
+ ExceptionUtils.dumpStack(System.err);
+ }
+ }
+ gl.glViewport(x, y, width, height);
+ gl.glClear(GL.GL_COLOR_BUFFER_BIT);
}
public final void reshape(final GLAutoDrawable drawable, final int x, final int y, final int width, final int height) {
+ setViewportAndClear(drawable, x, y, width, height);
synchronized(listenersLock) {
for (int i=0; i < listeners.size(); i++) {
- reshape(listeners.get(i), drawable, x, y, width, height, 0==i /* setViewport */, true /* checkInit */);
+ final GLEventListener l = listeners.get(i);
+ // GLEventListener may need to be init,
+ // in case this one is added after the realization of the GLAutoDrawable
+ if( listenersToBeInit.remove(l) ) {
+ l.init(drawable);
+ }
+ l.reshape(drawable, x, y, width, height);
}
}
}
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