Custom lighting funcs: are lightDir and viewDir passed normalized or not?

Unity Engine
1

When writing our own custom Lighting functions in Cg, we define a function that receives: in float3 lightDir and in float3 viewDir. I cannot work out from the docs whether those vectors are passed in normalized form or not. I need to have them in normalized form which I can do myself in Cg but I wouldn’t want the resulting built output shader to do the same “2x normalize()” work twice per pixel…

2

Yes, both are normalized per-pixel. Here’s a relevant bit from the generated code of a surface shader:

  // call surface function
  surf (surfIN, o);
  #ifndef USING_DIRECTIONAL_LIGHT
  fixed3 lightDir = normalize(IN.lightDir);
  #else
  fixed3 lightDir = IN.lightDir;
  #endif
  fixed4 c = LightingBlinnPhong (o, lightDir, normalize(half3(IN.viewDir)), LIGHT_ATTENUATION(IN));
3

Muchos gracias! I guess you did “open compiled shader” to check? Did the same meanwhile too :smile: at my end IN.viewDir is always passed normalized too, BUT unlike your setup, in my version IN.lightDir is never normalized (checked all permutations in the compiled-shader file) strangely. Well it probably is already normalized pre-shading at the CPU side (I’m not doing anything crazy with the dir light). Anyway, good to know… cheers :sunglasses: