IOS7: Render openGLContext

Implement callbacks to set up OpenGL context, destroy context, get
scale factor and screen sizes. Implement rendering of graphics drawn
by the iOS graphicsManager.

This commit will enable graphics to be shown again. Screen rotation
and mouse movements are still to be adapted.

backends/platform/ios7/ios7_osys_video.mm

@@ -276,33 +276,26 @@ bool OSystem_iOS7::isKeyboardShown() const {
 }
 
 uint OSystem_iOS7::createOpenGLContext() {
-	// TODO: Implement creation of OpenGL context
-	// The context will be used by scummvm system running on
-	// background thread.
-	return 0;
+	return [[iOS7AppDelegate iPhoneView] createOpenGLContext];
 }
 
 void OSystem_iOS7::destroyOpenGLContext() {
-	// TODO: Implement destroy of OpenGL context
+	[[iOS7AppDelegate iPhoneView] destroyOpenGLContext];
 }
 
 void OSystem_iOS7::refreshScreen() const {
-	// TODO: Implement presentation of the renderBuffer
-	// Present the renderBuffer on the openGLContext
+	[[iOS7AppDelegate iPhoneView] refreshScreen];
 }
 
 int OSystem_iOS7::getScreenWidth() const {
-	// TODO: Return width of screen buffer
-	return 0;
+	return [[iOS7AppDelegate iPhoneView] getScreenWidth];
 }
 
 int OSystem_iOS7::getScreenHeight() const {
-	// TODO: Return height of screen buffer
-	return 0;
+	return [[iOS7AppDelegate iPhoneView] getScreenHeight];
 }
 
 float OSystem_iOS7::getSystemHiDPIScreenFactor() const {
-	// TODO: Return HiDPI screen factor
-	return 0.0;
+	return [[UIScreen mainScreen] scale];
 }
 

backends/platform/ios7/ios7_video.h

@@ -54,7 +54,8 @@ uint getSizeNextPOT(uint size);
 
 	UIBackgroundTaskIdentifier _backgroundSaveStateTask;
 
-	EAGLContext *_context;
+	EAGLContext *_mainContext;
+	EAGLContext *_openGLContext;
 	GLuint _viewRenderbuffer;
 	GLuint _viewFramebuffer;
 	GLuint _screenTexture;
@@ -100,6 +101,12 @@ uint getSizeNextPOT(uint size);
 
 - (VideoContext *)getVideoContext;
 
+- (uint)createOpenGLContext;
+- (void)destroyOpenGLContext;
+- (void)refreshScreen;
+- (int)getScreenWidth;
+- (int)getScreenHeight;
+
 - (void)setGameScreenCoords;
 - (void)initSurface;
 - (void)setViewTransformation;

backends/platform/ios7/ios7_video.mm

@@ -123,22 +123,56 @@ uint getSizeNextPOT(uint size) {
 	                                 kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGBA8,
 	                                };
 
-	_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
+	_mainContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
 
 	// In case creating the OpenGL ES context failed, we will error out here.
-	if (_context == nil) {
+	if (_mainContext == nil) {
 		printError("Could not create OpenGL ES context.");
 		abort();
 	}
 
-	if ([EAGLContext setCurrentContext:_context]) {
-		// glEnableClientState(GL_TEXTURE_COORD_ARRAY); printOpenGLError();
-		// glEnableClientState(GL_VERTEX_ARRAY); printOpenGLError();
-		[self setupOpenGL];
+	// main thread will always use _mainContext
+	[EAGLContext setCurrentContext:_mainContext];
+}
+
+- (uint)createOpenGLContext {
+	// Create OpenGL context with the sharegroup from the context
+	// connected to the Apple Core Animation layer
+	if (!_openGLContext && _mainContext) {
+		_openGLContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2 sharegroup:_mainContext.sharegroup];
+
+		if (_openGLContext == nil) {
+			printError("Could not create OpenGL ES context using sharegroup");
+			abort();
+		}
+		// background thread will always use _openGLContext
+		if ([EAGLContext setCurrentContext:_openGLContext]) {
+			[self setupRenderBuffer];
+		}
 	}
+	return _viewRenderbuffer;
+}
+
+- (void)destroyOpenGLContext {
+	[_openGLContext release];
+	_openGLContext = nil;
+}
+
+- (void)refreshScreen {
+	glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer);
+	[_openGLContext presentRenderbuffer:GL_RENDERBUFFER];
+}
+
+- (int)getScreenWidth {
+	return _renderBufferWidth;
+}
+
+- (int)getScreenHeight {
+	return _renderBufferHeight;
 }
 
 - (void)setupOpenGL {
+	[self setupRenderBuffer];
 	[self setupFramebuffer];
 	[self createOverlaySurface];
 	[self compileShaders];
@@ -163,6 +197,7 @@ uint getSizeNextPOT(uint size) {
 	[self deleteVBOs];
 	[self deleteShaders];
 	[self deleteFramebuffer];
+	[self deleteRenderbuffer];
 }
 
 - (void)rebuildFrameBuffer {
@@ -172,32 +207,41 @@ uint getSizeNextPOT(uint size) {
 }
 
 - (void)setupFramebuffer {
-	glGenRenderbuffers(1, &_viewRenderbuffer);
-	printOpenGLError();
-	glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer);
-	printOpenGLError();
-	[_context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(id <EAGLDrawable>) self.layer];
-
-	glGenFramebuffers(1, &_viewFramebuffer);
-	printOpenGLError();
+   if (!_viewFramebuffer) {
+	   glGenFramebuffers(1, &_viewFramebuffer);
+	   printOpenGLError();
+	}
 	glBindFramebuffer(GL_FRAMEBUFFER, _viewFramebuffer);
 	printOpenGLError();
 	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _viewRenderbuffer);
 	printOpenGLError();
 
-	// Retrieve the render buffer size. This *should* match the frame size,
-	// i.e. g_fullWidth and g_fullHeight.
-	glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &_renderBufferWidth);
-	printOpenGLError();
-	glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_renderBufferHeight);
-	printOpenGLError();
-
 	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
 		NSLog(@"Failed to make complete framebuffer object %x.", glCheckFramebufferStatus(GL_FRAMEBUFFER));
 		return;
 	}
 }
 
+- (void)setupRenderBuffer {
+	execute_on_main_thread(^{
+		if (!_viewRenderbuffer) {
+			glGenRenderbuffers(1, &_viewRenderbuffer);
+			printOpenGLError();
+		}
+		glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer);
+		printOpenGLError();
+		if (![_mainContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:(id <EAGLDrawable>) self.layer]) {
+			printError("Failed renderbufferStorage");
+		}
+		// Retrieve the render buffer size. This *should* match the frame size,
+		// i.e. g_fullWidth and g_fullHeight.
+		glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &_renderBufferWidth);
+		printOpenGLError();
+		glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_renderBufferHeight);
+		printOpenGLError();
+	});
+}
+
 - (void)createOverlaySurface {
 	uint overlayWidth = (uint) MAX(_renderBufferWidth, _renderBufferHeight);
 	uint overlayHeight = (uint) MIN(_renderBufferWidth, _renderBufferHeight);
@@ -221,8 +265,11 @@ uint getSizeNextPOT(uint size) {
 	_videoContext.overlayTexture.create((uint16) overlayTextureWidthPOT, (uint16) overlayTextureHeightPOT, Graphics::PixelFormat(2, 5, 5, 5, 1, 11, 6, 1, 0));
 }
 
-- (void)deleteFramebuffer {
+- (void)deleteRenderbuffer {
 	glDeleteRenderbuffers(1, &_viewRenderbuffer);
+}
+
+- (void)deleteFramebuffer {
 	glDeleteFramebuffers(1, &_viewFramebuffer);
 }
 
@@ -538,7 +585,7 @@ uint getSizeNextPOT(uint size) {
 	if (_videoContext.mouseIsVisible)
 		[self updateMouseSurface];
 
-	[_context presentRenderbuffer:GL_RENDERBUFFER];
+	[_mainContext presentRenderbuffer:GL_RENDERBUFFER];
 	glFinish();
 }
 
@@ -682,9 +729,7 @@ uint getSizeNextPOT(uint size) {
 }
 
 - (void)initSurface {
-	if (_context) {
-		[self rebuildFrameBuffer];
-	}
+	[self setupRenderBuffer];
 
 #if TARGET_OS_IOS
 	UIInterfaceOrientation interfaceOrientation = UIInterfaceOrientationUnknown;
@@ -715,10 +760,6 @@ uint getSizeNextPOT(uint size) {
 		[self showKeyboard];
 	}
 
-	glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer); printOpenGLError();
-
-	[self clearColorBuffer];
-
 	GLfloat adjustedWidth = _videoContext.screenWidth;
 	GLfloat adjustedHeight = _videoContext.screenHeight;
 	if (_videoContext.asprectRatioCorrection) {
@@ -842,7 +883,7 @@ uint getSizeNextPOT(uint size) {
 	int clearCount = 5;
 	while (clearCount-- > 0) {
 		glClear(GL_COLOR_BUFFER_BIT); printOpenGLError();
-		[_context presentRenderbuffer:GL_RENDERBUFFER];
+		[_mainContext presentRenderbuffer:GL_RENDERBUFFER];
 		glFinish();
 	}
 }