ps.1.1
tex t0 ; base
tex t1 ; lightmap
tex t2 ; base (with tcoords for alpha)
mov r0.rgb, t0 ; base times vertex color (with alpha)
mul r0.rgb, t1, r0 ; fold in lightmap (color only)
mul_x2 r0.rgb, c0, r0 ; * 2 * (overbrightFactor/2)
mov r0.a, t2.a