SDL: Support fullscreen on RPI (#1398)

Uses 24 a depth buffer if possible on OpenGL ES

backends/graphics/openglsdl/openglsdl-graphics.cpp

@@ -476,10 +476,14 @@ void OpenGLSdlGraphicsManager::showOverlay() {
 	_overlayBackground = nullptr;
 
 	if (g_engine) {
+		if (_frameBuffer)
+			_frameBuffer->detach();
 		// If there is a game running capture the screen, so that it can be shown "below" the overlay.
 		_overlayBackground = new OpenGL::TiledSurface(_overlayWidth, _overlayHeight, _overlayFormat);
 		Graphics::Surface *background = _overlayBackground->getBackingSurface();
 		glReadPixels(0, 0, background->w, background->h, GL_RGBA, GL_UNSIGNED_BYTE, background->getPixels());
+		if (_frameBuffer)
+			_frameBuffer->attach();
 	}
 }
 

graphics/opengl/context.cpp

@@ -50,6 +50,7 @@ void Context::reset() {
 	packedDepthStencilSupported = false;
 	unpackSubImageSupported = false;
 	framebufferObjectMultisampleSupported = false;
+	OESDepth24 = false;
 	multisampleMaxSamples = -1;
 }
 
@@ -96,7 +97,10 @@ void Context::initialize(ContextType contextType) {
 			EXTFramebufferMultisample = true;
 		} else if (token == "GL_EXT_framebuffer_blit") {
 			EXTFramebufferBlit = true;
+		} else if (token == "GL_OES_depth24") {
+			OESDepth24 = true;
 		}
+		
 	}
 
 	int glslVersion = getGLSLVersion();

graphics/opengl/context.h

@@ -85,6 +85,9 @@ public:
 
 	/** Whether specifying a pitch when uploading to textures is available or not */
 	bool unpackSubImageSupported;
+	
+	/** Whether depth component 24 is supported or not */
+	bool OESDepth24;
 
 	int getGLSLVersion() const;
 };

graphics/opengl/framebuffer.cpp

@@ -49,6 +49,7 @@
 
 #ifdef USE_GLES2
 #define GL_DEPTH24_STENCIL8 GL_DEPTH24_STENCIL8_OES
+#define GL_DEPTH_COMPONENT24 GL_DEPTH_COMPONENT24_OES
 #endif
 
 namespace OpenGL {
@@ -115,6 +116,9 @@ static void grabFramebufferObjectPointers() {
 static bool usePackedBuffer() {
 	return OpenGLContext.packedDepthStencilSupported;
 }
+static bool useDepthComponent24() {
+	return OpenGLContext.OESDepth24;
+}
 
 FrameBuffer::FrameBuffer(uint width, uint height) :
 		Texture(width, height) {
@@ -154,7 +158,7 @@ void FrameBuffer::init() {
 		glBindRenderbuffer(GL_RENDERBUFFER, 0);
 	} else {
 		glBindRenderbuffer(GL_RENDERBUFFER, _renderBuffers[0]);
-		glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, _texWidth, _texHeight);
+		glRenderbufferStorage(GL_RENDERBUFFER, useDepthComponent24() ? GL_DEPTH_COMPONENT24 : GL_DEPTH_COMPONENT16, _texWidth, _texHeight);
 		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _renderBuffers[0]);
 
 		glBindRenderbuffer(GL_RENDERBUFFER, _renderBuffers[1]);