ShaderMaker For Lights

Why "Sample Once" ?
If you created a light shader for a particular light, it will add extra properties to that light. The renderer will have to evaluate (or sample) the influence of these additionnal properties for every surface lit by your light shader. To avoid slowing down the renderer in simple cases (like changing the color of the light from white to red), you have the option to "sample once" the extra properties of the light. Of course, if you want to use a spotlight as a slide projector, you will have to uncheck "Sample Once", or you will end up with a flat colored projection. "Sample Once" is on by default to let the renderer work as fast as possible.

Diffuse
Specular
Shadows