- Bidirectional reflectance distribution function
half u = dot(L, N) * 0.5 + 0.5;
half v = dot(V, N);
half3 brdfTex = SAMPLE_TEXTURE2D(_BrdfTex, sampler_BrdfTex, half2(u, v)).rgb;
- Schlick's approximation // fresnel
- Lazarov 2013
| |
|---|
| x | dot(V, N) // cosθv |
| y | Roughness |
| DFG | |
|---|
| D | Distrubution |
| F | Fresnel |
| G | Geometry |
Color c = diffuse * intensity + fresnelReflectionColor * fresnelTerm + translucentColor * t + Color(0, 0 ,0, specular);
c *= intensity;
half u = dot(L, N) * 0.5 + 0.5;
half v = dot(H, N);
half3 brdfTex = SAMPLE_TEXTURE2D(_BrdfTex, sampler_BrdfTex, half2(u, v)).rgb;
half3 color = albedo * (brdfTex.rgb + gloss * brdfTex.a) * 2;
// +--- B ---+ A : 빛과 마주치는 면
// | | B : 빛과 반대방향의 면
// D C C : 카메라와 마주치는 면
// | | D : 카메라와 90도 되는 면
// +--- A ---+
OffsetU // [-1, 1]
OffsetV // [-1, 1]
half2 brdfUV = float2(saturate(NdotV + OffsetU), saturate((LdotN + 1) * 0.5) + OffsetV);
brdfUV.y = 1 - brdfUV.y;
half3 brdfTex = tex2D(BRDFSampler, brdfUV).rgb;
half3 color = ambient + brdfTex;