From 9dcac079ce3f4654b787b44091f32995f7d97ca9 Mon Sep 17 00:00:00 2001
From: Guy Zadickario <amit@graphtech.co.il>
Date: Thu, 11 Aug 2011 15:14:35 +0300
Subject: [PATCH] opengles emulator: mac support binding context to pbuffer

On Mac it happens that when a context is bound to a pbuffer
and you want to bind it to a window (NSView) instead you must
release it from the pbuffer before binding the window by calling
clearDrawable handle of NSOpenGLContext.
This change added an override of NSOpenGLContext in order to track
to which drawable type the context was previously bound and
call clearDrawable when necessary.

Change-Id: Iece5ab16a46aa0d107ccb773986a6b280d09d181
---
 .../host/libs/Translator/EGL/MacNative.m      | 55 +++++++++++++++++--
 .../libs/libOpenglRender/NativeMacSubWindow.m |  1 +
 2 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/tools/emulator/opengl/host/libs/Translator/EGL/MacNative.m b/tools/emulator/opengl/host/libs/Translator/EGL/MacNative.m
index 225a79fe7..68286553f 100644
--- a/tools/emulator/opengl/host/libs/Translator/EGL/MacNative.m
+++ b/tools/emulator/opengl/host/libs/Translator/EGL/MacNative.m
@@ -18,6 +18,50 @@
 #include <OpenGL/OpenGL.h>
 #include "MacPixelFormatsAttribs.h"
 
+//
+// EmuGLContext inherit from NSOpenGLContext
+// and adds binding state for the context to know
+// if it was last bounded to a pbuffer or a window.
+// This is because after the context was bounded to
+// a Pbuffer, before we bind it to a window we must
+// release it form the pbuffer by calling the
+// clearDrawable method. We do not want to call clearDrawable
+// more than really needed since when it is called at a time
+// that a window is bounded to the context it will clear the
+// window content causing flickering effect.
+// Thererfore we call clearDrawable only when we bind the context
+// to a window and it was previously bound to a Pbuffer.
+//
+@interface EmuGLContext : NSOpenGLContext {
+    @private
+        int boundToPbuffer;
+        int boundToWin;
+}
+
+- (id) initWithFormat:(NSOpenGLPixelFormat *)pixelFormat shareContext:(NSOpenGLContext *)share;
+- (void) preBind:(int)forPbuffer;
+@end
+
+@implementation EmuGLContext
+- (id) initWithFormat:(NSOpenGLPixelFormat *)pixelFormat shareContext:(NSOpenGLContext *)share
+{
+    self = [super initWithFormat:pixelFormat shareContext:share];
+    if (self != nil) {
+        boundToPbuffer = 0;
+        boundToWin = 0;
+    }
+    return self;
+}
+
+- (void) preBind:(int)forPbuffer
+{
+    if ((!forPbuffer && boundToPbuffer)) {
+        [self clearDrawable]; 
+    }
+    boundToPbuffer = forPbuffer;
+    boundToWin = !boundToPbuffer;
+}
+@end
 
 int getNumPixelFormats(){
     int size;
@@ -38,17 +82,17 @@ void getPixelFormatAttrib(void* pixelFormat,int attrib,int* val){
 
 void* nsCreateContext(void* format,void* share){
     NSOpenGLPixelFormat* frmt = (NSOpenGLPixelFormat*)format;
-    return [[NSOpenGLContext alloc] initWithFormat:frmt shareContext:share];
+    return [[EmuGLContext alloc] initWithFormat:frmt shareContext:share];
 }
 
 void  nsPBufferMakeCurrent(void* context,void* nativePBuffer,int level){
-    NSOpenGLContext* ctx = (NSOpenGLContext *)context;
+    EmuGLContext* ctx = (EmuGLContext *)context;
     NSOpenGLPixelBuffer* pbuff = (NSOpenGLPixelBuffer *)nativePBuffer;
     if(ctx == nil){
         [NSOpenGLContext clearCurrentContext];
     } else {
         if(pbuff != nil){
-            [ctx clearDrawable];
+            [ctx preBind:1];
             [ctx setPixelBuffer:pbuff cubeMapFace:0 mipMapLevel:level currentVirtualScreen:0];
             [ctx makeCurrentContext];
         }
@@ -56,11 +100,12 @@ void  nsPBufferMakeCurrent(void* context,void* nativePBuffer,int level){
 }
 
 void nsWindowMakeCurrent(void* context,void* nativeWin){
-    NSOpenGLContext* ctx = (NSOpenGLContext *)context;
+    EmuGLContext* ctx = (EmuGLContext *)context;
     NSView* win = (NSView *)nativeWin;
     if(ctx == nil){
         [NSOpenGLContext clearCurrentContext];
     } else if (win != nil) {
+        [ctx preBind:0];
         [ctx setView: win];
         [ctx makeCurrentContext];
     }
@@ -82,7 +127,7 @@ void nsSwapInterval(int *interval){
 
 
 void nsDestroyContext(void* context){
-    NSOpenGLContext *ctx = (NSOpenGLContext*)context;
+    EmuGLContext *ctx = (EmuGLContext*)context;
     if(ctx != nil){
         [ctx release];
     }
diff --git a/tools/emulator/opengl/host/libs/libOpenglRender/NativeMacSubWindow.m b/tools/emulator/opengl/host/libs/libOpenglRender/NativeMacSubWindow.m
index 269b7ea0d..2ac39e809 100644
--- a/tools/emulator/opengl/host/libs/libOpenglRender/NativeMacSubWindow.m
+++ b/tools/emulator/opengl/host/libs/libOpenglRender/NativeMacSubWindow.m
@@ -50,6 +50,7 @@ EGLNativeWindowType createSubWindow(FBNativeWindowType p_window,
 void destroySubWindow(EGLNativeDisplayType dis,EGLNativeWindowType win){
     if(win){
         NSView *glView = (NSView *)win;
+        [glView removeFromSuperview];
         [glView release];
     }
 }