Rasterizer discard implementation

src/OpenGL/libGLESv2/Context.cpp

@@ -635,7 +635,6 @@ bool Context::isPrimitiveRestartFixedIndexEnabled() const
 
 void Context::setRasterizerDiscardEnabled(bool enabled)
 {
-    UNIMPLEMENTED();
     mState.rasterizerDiscardEnabled = enabled;
 }
 
@@ -3019,6 +3018,8 @@ void Context::applyState(GLenum drawMode)
 
         mDitherStateDirty = false;
     }
+
+	device->setRasterizerDiscard(mState.rasterizerDiscardEnabled);
 }
 
 GLenum Context::applyVertexBuffer(GLint base, GLint first, GLsizei count, GLsizei instanceId)
@@ -3356,6 +3357,11 @@ void Context::readPixels(GLint x, GLint y, GLsizei width, GLsizei height,
 
 void Context::clear(GLbitfield mask)
 {
+	if(mState.rasterizerDiscardEnabled)
+	{
+		return;
+	}
+
     Framebuffer *framebuffer = getDrawFramebuffer();
 
     if(!framebuffer || framebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
@@ -3400,7 +3406,7 @@ void Context::clear(GLbitfield mask)
 void Context::clearColorBuffer(GLint drawbuffer, void *value, sw::Format format)
 {
 	unsigned int rgbaMask = getColorMask();
-	if(device && rgbaMask)
+	if(device && rgbaMask && !mState.rasterizerDiscardEnabled)
 	{
 		int x0(0), y0(0), width(0), height(0);
 		egl::Image* image = getScissoredImage(drawbuffer, x0, y0, width, height, false);
@@ -3432,7 +3438,7 @@ void Context::clearColorBuffer(GLint drawbuffer, const GLfloat *value)
 
 void Context::clearDepthBuffer(GLint drawbuffer, const GLfloat *value)
 {
-	if(device && mState.depthMask)
+	if(device && mState.depthMask && !mState.rasterizerDiscardEnabled)
 	{
 		int x0(0), y0(0), width(0), height(0);
 		egl::Image* image = getScissoredImage(drawbuffer, x0, y0, width, height, true);
@@ -3446,7 +3452,7 @@ void Context::clearDepthBuffer(GLint drawbuffer, const GLfloat *value)
 
 void Context::clearStencilBuffer(GLint drawbuffer, const GLint *value)
 {
-	if(device && mState.stencilWritemask)
+	if(device && mState.stencilWritemask && !mState.rasterizerDiscardEnabled)
 	{
 		int x0(0), y0(0), width(0), height(0);
 		egl::Image* image = getScissoredImage(drawbuffer, x0, y0, width, height, true);
@@ -3460,7 +3466,7 @@ void Context::clearStencilBuffer(GLint drawbuffer, const GLint *value)
 
 void Context::clearDepthStencilBuffer(GLint drawbuffer, GLfloat depth, GLint stencil)
 {
-	if(device && (mState.depthMask || mState.stencilWritemask))
+	if(device && (mState.depthMask || mState.stencilWritemask) && !mState.rasterizerDiscardEnabled)
 	{
 		int x0(0), y0(0), width(0), height(0);
 		egl::Image* image = getScissoredImage(drawbuffer, x0, y0, width, height, true);

src/Renderer/Context.cpp

@@ -253,6 +253,8 @@ namespace sw
 		fillMode = FILL_SOLID;
 		shadingMode = SHADING_GOURAUD;
 
+		rasterizerDiscard = false;
+
 		depthCompareMode = DEPTH_LESS;
 		depthBufferEnable = true;
 		depthWriteEnable = true;

src/Renderer/Context.hpp

@@ -494,6 +494,7 @@ namespace sw
 		bool occlusionEnabled;
 
 		// Pixel processor states
+		bool rasterizerDiscard;
 		bool depthBufferEnable;
 		DepthCompareMode depthCompareMode;
 		bool depthWriteEnable;

src/Renderer/Renderer.cpp

@@ -821,7 +821,7 @@ namespace sw
 					startTick = time;
 				#endif
 
-				int visible = setupPrimitives(this, unit, count);
+				int visible = draw->setupState.rasterizerDiscard ? 0 : setupPrimitives(this, unit, count);
 
 				primitiveProgress[unit].visible = visible;
 				primitiveProgress[unit].references = clusterCount;
@@ -2315,6 +2315,11 @@ namespace sw
 		slopeDepthBias = slopeBias;
 	}
 
+	void Renderer::setRasterizerDiscard(bool rasterizerDiscard)
+	{
+		context->rasterizerDiscard = rasterizerDiscard;
+	}
+
 	void Renderer::setPixelShader(const PixelShader *shader)
 	{
 		context->pixelShader = shader;

src/Renderer/Renderer.hpp

@@ -340,6 +340,8 @@ namespace sw
 		virtual void setDepthBias(float bias);
 		virtual void setSlopeDepthBias(float slopeBias);
 
+		virtual void setRasterizerDiscard(bool rasterizerDiscard);
+
 		// Programmable pipelines
 		virtual void setPixelShader(const PixelShader *shader);
 		virtual void setVertexShader(const VertexShader *shader);

src/Renderer/SetupProcessor.cpp

@@ -89,6 +89,7 @@ namespace sw
 		state.pointSizeRegister = 0xF;   // No vertex point size
 
 		state.multiSample = context->getMultiSampleCount();
+		state.rasterizerDiscard = context->rasterizerDiscard;
 
 		if(context->vertexShader)
 		{

src/Renderer/SetupProcessor.hpp

@@ -49,6 +49,7 @@ namespace sw
 			bool slopeDepthBias            : 1;
 			bool vFace                     : 1;
 			unsigned int multiSample       : 3;   // 1, 2 or 4
+			bool rasterizerDiscard         : 1;
 
 			struct Gradient
 			{