message: Implement KHR_materials_emissive_strength
diff: @@ -1568,9 +1568,26 @@ NodePtr GLTFData::createOSPMaterial(const tinygltf::Material &mat)
  auto ospMat = createNode(matName, "luminous");
  if (emissiveColor != rgb(0.f)) {
  + // Material Extensions
  + const auto &exts = mat.extensions;
  +
  + float intensity = 1.f;
  +
  + // KHR_materials_emissive_strength
  + if (exts.find("KHR_materials_emissive_strength") != exts.end()) {
  + // (Not yet ratified)
  + // https://github.com/KhronosGroup/glTF/tree/KHR_materials_emissive_strength/extensions/2.0/Khronos/KHR_materials_emissive_strength
  + auto params = exts.find("KHR_materials_emissive_strength")->second;
  +
  + // default: 1.0
  + intensity = 1.f;
  + if (params.Has("emissiveStrength")) {
  + intensity = (float)params.Get("emissiveStrength").Get<double>();
  + }
  + }
  +
  ospMat->createChild("color", "rgb") = emissiveColor;
  - ospMat->createChild("intensity", "float") =
  - 20.f; // XXX what's good default intensity?
  + ospMat->createChild("intensity", "float") = intensity;
  // Already checked for constant color above.
  if (mat.emissiveTexture.index != -1) {
  