Cycles: take into account diffuse roughness for roughness baking.

Roughness baking previously defaulted to 1.0 for all diffuse materials,
now we also bake roughness values of Oren-Nayer and Principled Diffuse.

Differential Revision: https://developer.blender.org/D3115

1 files changed, 25 insertions, 3 deletions

diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h
index e3beff6675a..d8ff69ca241 100644
--- a/intern/cycles/kernel/closure/bsdf.h
+++ b/intern/cycles/kernel/closure/bsdf.h
@@ -36,20 +36,42 @@ CCL_NAMESPACE_BEGIN
 
 /* Returns the square of the roughness of the closure if it has roughness,
  * 0 for singular closures and 1 otherwise. */
-ccl_device_inline float bsdf_get_roughness_squared(const ShaderClosure *sc)
+ccl_device_inline float bsdf_get_specular_roughness_squared(const ShaderClosure *sc)
 {
 	if(CLOSURE_IS_BSDF_SINGULAR(sc->type)) {
 		return 0.0f;
 	}
 
 	if(CLOSURE_IS_BSDF_MICROFACET(sc->type)) {
-		MicrofacetBsdf *bsdf = (MicrofacetBsdf*) sc;
+		MicrofacetBsdf *bsdf = (MicrofacetBsdf*)sc;
 		return bsdf->alpha_x*bsdf->alpha_y;
 	}
 
 	return 1.0f;
 }
 
+ccl_device_inline float bsdf_get_roughness_squared(const ShaderClosure *sc)
+{
+	/* This version includes diffuse, mainly for baking Principled BSDF
+	 * where specular and metallic zero otherwise does not bake the
+	 * specified roughness parameter. */
+	if(sc->type == CLOSURE_BSDF_OREN_NAYAR_ID) {
+		OrenNayarBsdf *bsdf = (OrenNayarBsdf*)sc;
+		return sqr(sqr(bsdf->roughness));
+	}
+
+	if(sc->type == CLOSURE_BSDF_PRINCIPLED_DIFFUSE_ID) {
+		PrincipledDiffuseBsdf *bsdf = (PrincipledDiffuseBsdf*)sc;
+		return sqr(sqr(bsdf->roughness));
+	}
+
+	if(CLOSURE_IS_BSDF_DIFFUSE(sc->type)) {
+		return 0.0f;
+	}
+
+	return bsdf_get_specular_roughness_squared(sc);
+}
+
 ccl_device_forceinline int bsdf_sample(KernelGlobals *kg,
                                        ShaderData *sd,
                                        const ShaderClosure *sc,
@@ -176,7 +198,7 @@ ccl_device_forceinline int bsdf_sample(KernelGlobals *kg,
 		float threshold_squared = kernel_data.background.transparent_roughness_squared_threshold;
 
 		if(threshold_squared >= 0.0f) {
-			if(bsdf_get_roughness_squared(sc) <= threshold_squared) {
+			if(bsdf_get_specular_roughness_squared(sc) <= threshold_squared) {
 				label |= LABEL_TRANSMIT_TRANSPARENT;
 			}
 		}