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FBX2glTF
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Slightly better Blinn/Phong -> PBR. 

We're still gunshy from our previous attempts at coming up with metalilc
and roughness values from diffuse/specular/shininess, but this should be
safe: a high shininess means a low roughness, and vice versa.
This commit is contained in:
Par Winzell 2018-03-28 10:44:51 -07:00
parent 3f1590a26b
commit b3492194cf
1 changed files with 42 additions and 4 deletions
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46
src/Raw2Gltf.cpp
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@ -639,6 +639,16 @@ ModelData *Raw2Gltf(
TextureData *emissiveTexture = simpleTex(RAW_TEXTURE_USAGE_EMISSIVE).get();
TextureData *occlusionTexture = nullptr;
// acquire derived texture of single RawTextureUsage as *TextData, or nullptr if it doesn't exist
auto merge1Tex = [&](
const std::string tag,
RawTextureUsage usage,
const pixel_merger &combine,
bool outputHasAlpha
) -> std::shared_ptr<TextureData> {
return getDerivedTexture({ material.textures[usage] }, combine, tag, outputHasAlpha);
};
// acquire derived texture of two RawTextureUsage as *TextData, or nullptr if neither exists
auto merge2Tex = [&](
const std::string tag,
@ -706,13 +716,41 @@ ModelData *Raw2Gltf(
*/
const RawTraditionalMatProps *props = ((RawTraditionalMatProps *) material.info.get());
diffuseFactor = props->diffuseFactor;
if (material.info->shadingModel == RAW_SHADING_MODEL_LAMBERT) {
if (material.info->shadingModel == RAW_SHADING_MODEL_BLINN ||
material.info->shadingModel == RAW_SHADING_MODEL_PHONG)
{
// blinn/phong hardcoded to 0.4 metallic
metallic = 0.4f;
// fairly arbitrary formula chosen such that
// shininess 0 -> roughness 1
// shininess 5 -> roughness 0.5
// as shininess ==> oo, roughness ==> 0
auto getRoughness = [&](float shininess) {
return 1.0f / (1.0f + shininess/5);
};
aoMetRoughTex = merge1Tex("ao_met_rough",
RAW_TEXTURE_USAGE_SHININESS,
[&](const std::vector<const pixel *> pixels) -> pixel {
// do not multiply with props->shininess; that doesn't work like the other factors.
float shininess = (*pixels[0])[0];
return { 0, getRoughness(shininess), metallic, 0 };
},
false);
if (aoMetRoughTex != nullptr) {
// if we successfully built a texture, factors are just multiplicative identity
metallic = roughness = 1.0f;
} else {
// no shininess texture,
roughness = getRoughness(props->shininess);
}
} else {
metallic = 0.2f;
roughness = 0.8f;
} else {
metallic = 0.4f;
roughness = 0.6f;
}
baseColorTex = simpleTex(RAW_TEXTURE_USAGE_DIFFUSE);
emissiveFactor = props->emissiveFactor;