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

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: