Ps
From Odwiki
In VEX and RSL, the Ps variable represents the position of the surface being shaded from within a LightShader (or ShadowShader in VEX). It's value is undefined in other shading contexts.
In VEX and RSL, the Ps variable represents the position of the surface being shaded from within a LightShader (or ShadowShader in VEX). It's value is undefined in other shading contexts.