Add IMaterialRendererServices::startUseProgram/stopUseProgram

This makes it possible to set high-level shader constants (which are attached to shader programs) to be set outside
of OnSetConstants.
IShaderConstantSetCallBack::OnCreate has it set automatically now so it works the same as OnSetConstants.
D3D9 and burnings both work different, so there hadn't been a problem with those.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6469 dfc29bdd-3216-0410-991c-e03cc46cb475

examples/10.Shaders/main.cpp

@@ -56,7 +56,7 @@ public:
 	{
 		if (UseHighLevelShaders)
 		{
-			// get shader constants id.
+			// Get shader constants id.
 			WorldViewProjID = services->getVertexShaderConstantID("mWorldViewProj");
 			TransWorldID = services->getVertexShaderConstantID("mTransWorld");
 			InvWorldID = services->getVertexShaderConstantID("mInvWorld");
@@ -68,6 +68,27 @@ public:
 			if(driver->getDriverType() == video::EDT_OPENGL)
 				TextureID = services->getVertexShaderConstantID("myTexture");
 		}
+
+		// Set light color 
+		// That could be set as well in OnSetConstants, but there's some cost to setting shader constants
+		// So when we have non-changing shader constants it's more performant to set them only once.
+		video::SColorf col(0.0f,1.0f,1.0f,0.0f);
+		if (UseHighLevelShaders)
+		{
+			services->setVertexShaderConstant(ColorID, reinterpret_cast<f32*>(&col), 4);
+
+			// Note: Since Irrlicht 1.9 it's possible to call setVertexShaderConstant 
+			// from anywhere. To do that save the services pointer here in OnCreate, it
+			// won't change as long as you use one IShaderConstantSetCallBack per shader
+			// material. But when calling it ouside of IShaderConstantSetCallBack functions
+			// you have to call services->startUseProgram()stopUseProgram() before/after doing so. 
+			// At least for high-level shader constants, low level constants are not attached
+			// to programs, so for those it doesn't matter.
+			// Doing that sometimes makes sense for performance reasons, like for constants which
+			// do only change once per frame or even less.
+		}
+		else
+			services->setVertexShaderConstant(reinterpret_cast<f32*>(&col), 9, 1);
 	}
 
 	virtual void OnSetConstants(video::IMaterialRendererServices* services,
@@ -109,16 +130,6 @@ public:
 		else
 			services->setVertexShaderConstant(reinterpret_cast<f32*>(&pos), 8, 1);
 
-		// set light color
-
-		video::SColorf col(0.0f,1.0f,1.0f,0.0f);
-
-		if (UseHighLevelShaders)
-			services->setVertexShaderConstant(ColorID,
-					reinterpret_cast<f32*>(&col), 4);
-		else
-			services->setVertexShaderConstant(reinterpret_cast<f32*>(&col), 9, 1);
-
 		// set transposed world matrix
 
 		core::matrix4 world = driver->getTransform(video::ETS_WORLD);

include/IMaterialRendererServices.h

@@ -41,6 +41,20 @@ public:
 	//! Return an index constant for the vertex shader based on a name.
 	virtual s32 getVertexShaderConstantID(const c8* name) = 0;
 
+	//! Call when you set shader constants outside of IShaderConstantSetCallBack
+	/** Only for high-level shader functions, aka those using an index instead of 
+	an register. Shader constants are attached to shader programs, so if you want 
+	to set them you have to make sure the correct shader program is in use.
+	IShaderConstantSetCallBack functions like OnSetConstants do that for you,
+	but if you want to set shader constants outside of those (usually for performance
+	reasons) call startUseProgram() before doing so and stopUseProgram() afterwards.
+	Note: Currently only necessary in OpenGL, but no real calling costs on other drivers.
+	*/
+	virtual void startUseProgram() {}
+
+	//! Call this when you are done setting shader constants outside of OnCreate or OnSetConstants 
+	virtual void stopUseProgram() {}
+
 	//! Sets a constant for the vertex shader based on a name.
 	/** This can be used if you used a high level shader language like GLSL
 	or HLSL to create a shader. Example: If you created a shader which has

source/Irrlicht/COpenGLDriver.cpp

@@ -3727,7 +3727,9 @@ s32 COpenGLDriver::addShaderMaterial(const c8* vertexShaderProgram,
 	r->drop();
 
 	if (callback && nr >= 0)
+	{
 		callback->OnCreate(this, userData);
+	}
 
 	return nr;
 }
@@ -3764,7 +3766,11 @@ s32 COpenGLDriver::addHighLevelShaderMaterial(
 	r->drop();
 
 	if (callback && nr >= 0)
+	{
+		r->startUseProgram();
 		callback->OnCreate(r, userData);
+		r->stopUseProgram();
+	}
 
 	return nr;
 }

source/Irrlicht/COpenGLDriver.h

@@ -415,6 +415,12 @@ namespace video
 		//! Get current material.
 		const SMaterial& getCurrentMaterial() const;
 
+		//! Rest renderstates forcing stuff like OnSetMaterial to be called
+		void DoResetRenderStates() 
+		{
+			ResetRenderStates = true;
+		}
+
 		COpenGLCacheHandler* getCacheHandler() const;
 
 	private:

source/Irrlicht/COpenGLSLMaterialRenderer.cpp

@@ -237,13 +237,10 @@ void COpenGLSLMaterialRenderer::OnSetMaterial(const video::SMaterial& material,
 
 	COpenGLCacheHandler* cacheHandler = Driver->getCacheHandler();
 
-	if (material.MaterialType != lastMaterial.MaterialType || resetAllRenderstates)
-	{
-		if (Program2)
-			Driver->irrGlUseProgram(Program2);
-		else if (Program)
-			Driver->extGlUseProgramObject(Program);
-	}
+	if (Program2)
+		Driver->irrGlUseProgram(Program2);
+	else if (Program)
+		Driver->extGlUseProgramObject(Program);
 
 	Driver->setBasicRenderStates(material, lastMaterial, resetAllRenderstates);
 
@@ -572,6 +569,23 @@ void COpenGLSLMaterialRenderer::setBasicRenderStates(const SMaterial& material,
 	Driver->setBasicRenderStates(material, lastMaterial, resetAllRenderstates);
 }
 
+void COpenGLSLMaterialRenderer::startUseProgram()
+{
+	if (Program2)
+		Driver->irrGlUseProgram(Program2);
+	else if (Program)
+		Driver->extGlUseProgramObject(Program);
+}
+
+void COpenGLSLMaterialRenderer::stopUseProgram()
+{
+	// Not going to reset irrGlUseProgram/extGlUseProgramObject as it shouldn't really matter
+
+	// Force reset of material to ensure OnSetMaterial will be called or we can miss 
+	// the next UseProgram call
+	Driver->DoResetRenderStates();
+}
+
 s32 COpenGLSLMaterialRenderer::getVertexShaderConstantID(const c8* name)
 {
 	return getPixelShaderConstantID(name);

source/Irrlicht/COpenGLSLMaterialRenderer.h

@@ -73,6 +73,8 @@ public:
 
 	// implementations for IMaterialRendererServices
 	virtual void setBasicRenderStates(const SMaterial& material, const SMaterial& lastMaterial, bool resetAllRenderstates) IRR_OVERRIDE;
+	virtual void startUseProgram() IRR_OVERRIDE;
+	virtual void stopUseProgram() IRR_OVERRIDE;
 	virtual s32 getVertexShaderConstantID(const c8* name) IRR_OVERRIDE;
 	virtual s32 getPixelShaderConstantID(const c8* name) IRR_OVERRIDE;
 	virtual void setVertexShaderConstant(const f32* data, s32 startRegister, s32 constantAmount=1) IRR_OVERRIDE;