worldvertextransition.psh

hl2 source code. Do not use it illegal.

ps.1.1

tex t0 ; basetexture
tex t1 ; basetexture2
tex t2 ; lightmap

mov_sat r1.a, 1-t2.a
lrp r0, r1.a, t1, t0
mul r0, r0, t2
mul_x2 r0.rgb, c0, r0   ; * 2 * (overbrightFactor/2)