dielectricSpecularF0 static method

@visibleForTesting Vector3 dielectricSpecularF0({ required double ior, required double specular, required Vector4 specularColor, })

The dielectric specular reflectance at normal incidence the standard shader path uses for these inputs, clamp(((ior - 1) / (ior + 1))^2 * specularColor * specular, 0, 1) per KHR_materials_ior and KHR_materials_specular, which is the same product the physical shader forms from its material inputs. Returns 0.04 for the defaults.

Implementation

@visibleForTesting
static Vector3 dielectricSpecularF0({
  required double ior,
  required double specular,
  required Vector4 specularColor,
}) {
  final clampedIor = math.max(ior, 1.0);
  final iorF0 = math.pow((clampedIor - 1.0) / (clampedIor + 1.0), 2.0);
  return Vector3(
    (iorF0 * specularColor.x * specular).clamp(0.0, 1.0).toDouble(),
    (iorF0 * specularColor.y * specular).clamp(0.0, 1.0).toDouble(),
    (iorF0 * specularColor.z * specular).clamp(0.0, 1.0).toDouble(),
  );
}