A graphics system includes an effect engine and a graphics pipeline. The graphics pipeline performs pipeline operations on graphical objects in a frame. The graphics pipeline includes at least a fragment shader stage. An application programming interface (API) provides an instruction that specifies a subset of the graphical objects in the frame for the effect engine to execute. When detecting the instruction, the graphics pipeline invokes the effect engine to perform a predefined set of graphics operations on the subset of the graphical objects in the frame. The predefined set of graphics operations has a higher computational complexity than the pipeline operations.