This function resets the shader used for drawing and should be called when you no longer wish to use the current shader (set using shader_set()).
shader_reset();
N/A
shader_set(shader_Glass);
draw_self();
shader_reset();
The above code will set a shader to be used for drawing, then draw the current sprite used for the instance using it. Finally it will reset the shader to revert to GameMaker's default shader.