From 019a1418c6e7768d2cde602b8bb77de6c8446a94 Mon Sep 17 00:00:00 2001
From: Elias Naur <elias.naur@gmail.com>
Date: Thu, 28 Apr 2005 12:55:23 +0000
Subject: [PATCH] Mac OS X: Added a workaround for the 'white screen' problem

---
 .../opengl/MacOSXContextImplementation.java   | 12 +++++++
 src/java/org/lwjgl/opengl/MacOSXDisplay.java  | 31 ++++++++++++++++++-
 src/java/org/lwjgl/opengl/MacOSXGLCanvas.java | 11 +++++++
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/java/org/lwjgl/opengl/MacOSXContextImplementation.java b/src/java/org/lwjgl/opengl/MacOSXContextImplementation.java
index abf0c379..48adea91 100644
--- a/src/java/org/lwjgl/opengl/MacOSXContextImplementation.java
+++ b/src/java/org/lwjgl/opengl/MacOSXContextImplementation.java
@@ -81,6 +81,18 @@ final class MacOSXContextImplementation implements ContextImplementation {
 
 	private static native void clearDrawable(ByteBuffer handle) throws LWJGLException;
 
+	static void resetView(PeerInfo peer_info, Context context) throws LWJGLException {
+		ByteBuffer peer_handle = peer_info.lockAndGetHandle();
+		try {
+			synchronized (context) {
+				clearDrawable(context.getHandle());
+				setView(peer_handle, context.getHandle());
+			}
+		} finally {
+			peer_info.unlock();
+		}
+	}
+	
 	public void makeCurrent(PeerInfo peer_info, ByteBuffer handle) throws LWJGLException {
 		ByteBuffer peer_handle = peer_info.lockAndGetHandle();
 		try {
diff --git a/src/java/org/lwjgl/opengl/MacOSXDisplay.java b/src/java/org/lwjgl/opengl/MacOSXDisplay.java
index 570858f6..51bfa05d 100644
--- a/src/java/org/lwjgl/opengl/MacOSXDisplay.java
+++ b/src/java/org/lwjgl/opengl/MacOSXDisplay.java
@@ -208,7 +208,36 @@ final class MacOSXDisplay implements DisplayImplementation {
 	}
 
 	public void update() {
-		if (frame.getCanvas().syncShouldUpdateContext()) {
+		boolean should_update = frame.getCanvas().syncShouldUpdateContext();
+		/*
+		 * Workaround for the "white screen in fullscreen mode" problem
+		 *
+		 * Sometimes, switching from windowed mode to fullscreen or simply creating the Display
+		 * in fullscreen mode will result in the context not being bound to the window correctly.
+		 * The program runs fine, but the canvas background (white) is shown instead of the context
+		 * front buffer.
+		 *
+		 * I've discovered that re-binding the context with another setView() won't fix the problem, while a
+		 * clearDrawable() followed by a setView() does work. A straightforward workaround would be
+		 * to simply run the combination at every update(). This is not sufficient, since the clearDrawable()
+		 * call makes the the background appear shortly, causing visual artifacts.
+		 * What we really need is a way to detect that a setView() failed, and then do the magic combo. I've not
+		 * been able to find such a detection so alternatively I'm triggering the combo if the display is fullscreen
+		 * (I've not seen the white screen problem in windowed mode) and if the canvas has gotten a paint message or
+		 * if its update flag was set.
+		 *
+		 * My testing seems to indicate that the workaround works, since I've not seen the problem after the fix.
+		 *
+		 * - elias
+		 */
+		if (Display.isFullscreen() && (frame.getCanvas().syncCanvasPainted() || should_update)) {
+			try {
+				MacOSXContextImplementation.resetView(Display.getContext().getPeerInfo(), Display.getContext());
+			} catch (LWJGLException e) {
+				LWJGLUtil.log("Failed to reset context: " + e);
+			}
+		}
+		if (should_update) {
 			Display.getContext().update();
 			/* This is necessary to make sure the context won't "forget" about the view size */
 			GL11.glViewport(0, 0, frame.getCanvas().syncGetWidth(), frame.getCanvas().syncGetHeight());
diff --git a/src/java/org/lwjgl/opengl/MacOSXGLCanvas.java b/src/java/org/lwjgl/opengl/MacOSXGLCanvas.java
index 74a35a76..5a0e9caa 100644
--- a/src/java/org/lwjgl/opengl/MacOSXGLCanvas.java
+++ b/src/java/org/lwjgl/opengl/MacOSXGLCanvas.java
@@ -50,6 +50,7 @@ final class MacOSXGLCanvas extends Canvas implements ComponentListener, Hierarch
 	private int width;
 	private int height;
 	private boolean context_update;
+	private boolean canvas_painted;
 	private boolean dirty;
 
 	public void update(Graphics g) {
@@ -59,6 +60,7 @@ final class MacOSXGLCanvas extends Canvas implements ComponentListener, Hierarch
 	public void paint(Graphics g) {
 		synchronized ( this ) {
 			dirty = true;
+			canvas_painted = true;
 		}
 	}
 
@@ -75,6 +77,15 @@ final class MacOSXGLCanvas extends Canvas implements ComponentListener, Hierarch
 		setUpdate();
 	}
 
+	public boolean syncCanvasPainted() {
+		boolean result;
+		synchronized (this) {
+			result = canvas_painted;
+			canvas_painted = false;
+		}
+		return result;
+	}
+
 	public boolean syncIsDirty() {
 		boolean result;
 		synchronized ( this ) {