GuiShader::GuiShader(const ref_ptr<graphics::Context>& context, const string& vertexShader, const string& fragmentShader) : context(context), shaderProgram(context->createShaderProgram(vertexShader, fragmentShader)), shaderParamMvp(shaderProgram->getParameter("ModelViewProjectionMatrix")), shaderParamMvpValue(), shaderParamMvpDirty(true), shaderParamTexture(shaderProgram->getParameter("Texture")), shaderParamTextureDirty(true) { }