IOS7: Add support for 32 bit pixel formats

This enables some game engines only supporting 32 bit color formats,
e.g. 11th hour and Broken Sword 2.5.

Add support for the pixel formats RGBA8888 and ABGR8888. The pixel
formats are defined in big endian while iOS utilizes little endian,
thus requiring converting some formats to get correct color
representation.

Use the Apple Accelerate framework converting the format requiring
to minimize the CPU load since this is done every frame.

backends/platform/ios7/ios7_osys_video.mm

@@ -103,6 +103,10 @@ void OSystem_iOS7::initVideoContext() {
 #ifdef USE_RGB_COLOR
 Common::List<Graphics::PixelFormat> OSystem_iOS7::getSupportedFormats() const {
 	Common::List<Graphics::PixelFormat> list;
+	// ABGR8888 (big endian)
+	list.push_back(Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24));
+	// RGBA8888 (big endian)
+	list.push_back(Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0));
 	// RGB565
 	list.push_back(Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0));
 	// CLUT8
@@ -140,9 +144,19 @@ void OSystem_iOS7::initSize(uint width, uint height, const Graphics::PixelFormat
 	// Create the screen texture right here. We need to do this here, since
 	// when a game requests hi-color mode, we actually set the framebuffer
 	// to the texture buffer to avoid an additional copy step.
-	execute_on_main_thread(^ {
-		[[iOS7AppDelegate iPhoneView] createScreenTexture];
-	});
+	// Free any previous screen texture and create new to handle format changes
+	_videoContext->screenTexture.free();
+
+	if (format && *format == Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24)) {
+		// ABGR8888 (big endian)
+		_videoContext->screenTexture.create((uint16) getSizeNextPOT(_videoContext->screenWidth), (uint16) getSizeNextPOT(_videoContext->screenHeight), Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24));
+	} else if (format && *format == Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0)) {
+		// RGBA8888 (big endian)
+		_videoContext->screenTexture.create((uint16) getSizeNextPOT(_videoContext->screenWidth), (uint16) getSizeNextPOT(_videoContext->screenHeight), Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0));
+	} else {
+		// Assume RGB565
+		_videoContext->screenTexture.create((uint16) getSizeNextPOT(_videoContext->screenWidth), (uint16) getSizeNextPOT(_videoContext->screenHeight), Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0));
+	}
 
 	// In case the client code tries to set up a non supported mode, we will
 	// fall back to CLUT8 and set the transaction error accordingly.
@@ -151,6 +165,10 @@ void OSystem_iOS7::initSize(uint width, uint height, const Graphics::PixelFormat
 		_gfxTransactionError = kTransactionFormatNotSupported;
 	}
 
+	execute_on_main_thread(^{
+		[[iOS7AppDelegate iPhoneView] setGameScreenCoords];
+	});
+
 	if (!format || format->bytesPerPixel == 1) {
 		_framebuffer.create(width, height, Graphics::PixelFormat::createFormatCLUT8());
 	} else {

backends/platform/ios7/ios7_video.h

@@ -25,6 +25,7 @@
 #include <UIKit/UIKit.h>
 #include <Foundation/Foundation.h>
 #include <QuartzCore/QuartzCore.h>
+#include <Accelerate/Accelerate.h>
 
 #include <OpenGLES/EAGL.h>
 #include <OpenGLES/ES2/gl.h>
@@ -41,6 +42,8 @@ typedef struct {
 	GLfloat u,v;
 } GLVertex;
 
+uint getSizeNextPOT(uint size);
+
 @interface iPhoneView : UIView {
 	VideoContext _videoContext;
 
@@ -97,7 +100,7 @@ typedef struct {
 
 - (VideoContext *)getVideoContext;
 
-- (void)createScreenTexture;
+- (void)setGameScreenCoords;
 - (void)initSurface;
 - (void)setViewTransformation;
 

backends/platform/ios7/ios7_video.mm

@@ -120,7 +120,7 @@ uint getSizeNextPOT(uint size) {
 	eaglLayer.opaque = YES;
 	eaglLayer.drawableProperties = @{
 	                                 kEAGLDrawablePropertyRetainedBacking: @NO,
-	                                 kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGB565
+	                                 kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGBA8,
 	                                };
 
 	_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
@@ -603,6 +603,30 @@ uint getSizeNextPOT(uint size) {
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _videoContext.mouseTexture.w, _videoContext.mouseTexture.h, 0, GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, _videoContext.mouseTexture.getPixels()); printOpenGLError();
 }
 
+- (void *)getTextureInRGBA8888BE_AsRGBA8888LE {
+	// Allocate a pixel buffer with 32 bits per pixel
+	void *pixelBuffer = malloc(_videoContext.screenTexture.h * _videoContext.screenTexture.w * sizeof(uint32_t));
+	// Copy the texture pixels as we don't want to operate on the
+	memcpy(pixelBuffer, _videoContext.screenTexture.getPixels(), _videoContext.screenTexture.h * _videoContext.screenTexture.w * sizeof(uint32_t));
+
+	// Utilize the Accelerator Framwork to do some byte swapping
+	vImage_Buffer src;
+	src.height = _videoContext.screenTexture.h;
+	src.width = _videoContext.screenTexture.w;
+	src.rowBytes = _videoContext.screenTexture.pitch;
+	src.data = _videoContext.screenTexture.getPixels();
+
+	// Initialise dst with src, change data pointer to pixelBuffer
+	vImage_Buffer dst = src;
+	dst.data = pixelBuffer;
+
+	// Swap pixel channels from RGBA BE to RGBA LE (ABGR)
+	const uint8_t map[4] = { 3, 2, 1, 0 };
+	vImagePermuteChannels_ARGB8888(&src, &dst, map, kvImageNoFlags);
+
+	return pixelBuffer;
+}
+
 - (void)updateMainSurface {
 	glBufferData(GL_ARRAY_BUFFER, sizeof(GLVertex) * 4, _gameScreenCoords, GL_STATIC_DRAW);
 	glVertexAttribPointer(_positionSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), 0);
@@ -613,8 +637,18 @@ uint getSizeNextPOT(uint size) {
 	// Unfortunately we have to update the whole texture every frame, since glTexSubImage2D is actually slower in all cases
 	// due to the iPhone internals having to convert the whole texture back from its internal format when used.
 	// In the future we could use several tiled textures instead.
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _videoContext.screenTexture.w, _videoContext.screenTexture.h, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, _videoContext.screenTexture.getPixels()); printOpenGLError();
-
+	if (_videoContext.screenTexture.format == Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24)) {
+		// ABGR8888 in big endian which in little endian is RBGA8888 -> no convertion needed
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _videoContext.screenTexture.w, _videoContext.screenTexture.h, 0, GL_RGBA, GL_UNSIGNED_BYTE, _videoContext.screenTexture.getPixels()); printOpenGLError();
+	} else if (_videoContext.screenTexture.format == Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0)) {
+		// RGBA8888 (big endian) = ABGR8888 (little endian) -> needs convertion
+		void* pixelBuffer = [self getTextureInRGBA8888BE_AsRGBA8888LE];
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _videoContext.screenTexture.w, _videoContext.screenTexture.h, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixelBuffer); printOpenGLError();
+		free(pixelBuffer);
+	} else {
+		// Assuming RGB565
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _videoContext.screenTexture.w, _videoContext.screenTexture.h, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, _videoContext.screenTexture.getPixels()); printOpenGLError();
+	}
 	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); printOpenGLError();
 }
 
@@ -639,14 +673,12 @@ uint getSizeNextPOT(uint size) {
 	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); printOpenGLError();
 }
 
-- (void)createScreenTexture {
+- (void)setGameScreenCoords{
 	const uint screenTexWidth = getSizeNextPOT(_videoContext.screenWidth);
 	const uint screenTexHeight = getSizeNextPOT(_videoContext.screenHeight);
 
 	_gameScreenCoords[1].u = _gameScreenCoords[3].u = _videoContext.screenWidth / (GLfloat)screenTexWidth;
 	_gameScreenCoords[2].v = _gameScreenCoords[3].v = _videoContext.screenHeight / (GLfloat)screenTexHeight;
-
-	_videoContext.screenTexture.create((uint16) screenTexWidth, (uint16) screenTexHeight, Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0));
 }
 
 - (void)initSurface {