How to apply decal without lerp

Unity Engine
1

Hello!

I’d like to apply decal to my texture in surface shader, and I’ve run out of instructions (need to add to more multiplications and don’t want to use sm3.0) - so I’d like to replace

o.Albedo = lerp (tex.rgb, decal.rgb, decal.a);

with some other operation (I don’t need decal transparency, I only need it to be only 0\1) to reduce instruction count.

2

Well, a lerp is actually really cheap; not sure how could you replace it without changing the behavior. “lerp (a,b,t)” is the same as “a*(1-t) + b*t”, so it probably compiles into something like two instructions.