Cycles: add roughness baking support, using squared roughness convention.

3 files changed, 45 insertions, 16 deletions

diff --git a/intern/cycles/kernel/kernel_bake.h b/intern/cycles/kernel/kernel_bake.h
index b3c2450d10e..79e6d1b4862 100644
--- a/intern/cycles/kernel/kernel_bake.h
+++ b/intern/cycles/kernel/kernel_bake.h
@@ -330,15 +330,30 @@ ccl_device void kernel_bake_evaluate(KernelGlobals *kg, ccl_global uint4 *input,
 	switch(type) {
 		/* data passes */
 		case SHADER_EVAL_NORMAL:
+		case SHADER_EVAL_ROUGHNESS:
+		case SHADER_EVAL_EMISSION:
 		{
-			float3 N = sd.N;
-			if((sd.flag & SD_HAS_BUMP)) {
-				shader_eval_surface(kg, &sd, &state, 0);
-				N = shader_bsdf_average_normal(kg, &sd);
+			if(type != SHADER_EVAL_NORMAL || (sd.flag & SD_HAS_BUMP)) {
+				int path_flag = (type == SHADER_EVAL_EMISSION) ? PATH_RAY_EMISSION : 0;
+				shader_eval_surface(kg, &sd, &state, path_flag);
 			}
 
-			/* encoding: normal = (2 * color) - 1 */
-			out = N * 0.5f + make_float3(0.5f, 0.5f, 0.5f);
+			if(type == SHADER_EVAL_NORMAL) {
+				float3 N = sd.N;
+				if(sd.flag & SD_HAS_BUMP) {
+					N = shader_bsdf_average_normal(kg, &sd);
+				}
+
+				/* encoding: normal = (2 * color) - 1 */
+				out = N * 0.5f + make_float3(0.5f, 0.5f, 0.5f);
+			}
+			else if(type == SHADER_EVAL_ROUGHNESS) {
+				float roughness = shader_bsdf_average_roughness(&sd);
+				out = make_float3(roughness, roughness, roughness);
+			}
+			else {
+				out = shader_emissive_eval(kg, &sd);
+			}
 			break;
 		}
 		case SHADER_EVAL_UV:
@@ -346,13 +361,6 @@ ccl_device void kernel_bake_evaluate(KernelGlobals *kg, ccl_global uint4 *input,
 			out = primitive_uv(kg, &sd);
 			break;
 		}
-		case SHADER_EVAL_EMISSION:
-		{
-			shader_eval_surface(kg, &sd, &state, PATH_RAY_EMISSION);
-			out = shader_emissive_eval(kg, &sd);
-			break;
-		}
-
 #ifdef __PASSES__
 		/* light passes */
 		case SHADER_EVAL_AO:
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index fc8d06fc33d..937a50cba8b 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -763,6 +763,26 @@ ccl_device int shader_bsdf_sample_closure(KernelGlobals *kg, ShaderData *sd,
 	return label;
 }
 
+ccl_device float shader_bsdf_average_roughness(ShaderData *sd)
+{
+	float roughness = 0.0f;
+	float sum_weight = 0.0f;
+
+	for(int i = 0; i < sd->num_closure; i++) {
+		ShaderClosure *sc = &sd->closure[i];
+
+		if(CLOSURE_IS_BSDF(sc->type)) {
+			/* sqrt once to undo the squaring from multiplying roughness on the
+			 * two axes, and once for the squared roughness convention. */
+			float weight = fabsf(average(sc->weight));
+			roughness += weight * sqrtf(safe_sqrtf(bsdf_get_roughness_squared(sc)));
+			sum_weight += weight;
+		}
+	}
+
+	return (sum_weight > 0.0f) ? roughness / sum_weight : 0.0f;
+}
+
 ccl_device void shader_bsdf_blur(KernelGlobals *kg, ShaderData *sd, float roughness)
 {
 	for(int i = 0; i < sd->num_closure; i++) {
@@ -875,7 +895,7 @@ ccl_device float3 shader_bsdf_average_normal(KernelGlobals *kg, ShaderData *sd)
 	for(int i = 0; i < sd->num_closure; i++) {
 		ShaderClosure *sc = &sd->closure[i];
 		if(CLOSURE_IS_BSDF_OR_BSSRDF(sc->type))
-			N += sc->N*average(sc->weight);
+			N += sc->N*fabsf(average(sc->weight));
 	}
 
 	return (is_zero(N))? sd->N : normalize(N);
@@ -892,11 +912,11 @@ ccl_device float3 shader_bsdf_ao(KernelGlobals *kg, ShaderData *sd, float ao_fac
 		if(CLOSURE_IS_BSDF_DIFFUSE(sc->type)) {
 			const DiffuseBsdf *bsdf = (const DiffuseBsdf*)sc;
 			eval += sc->weight*ao_factor;
-			N += bsdf->N*average(sc->weight);
+			N += bsdf->N*fabsf(average(sc->weight));
 		}
 		else if(CLOSURE_IS_AMBIENT_OCCLUSION(sc->type)) {
 			eval += sc->weight;
-			N += sd->N*average(sc->weight);
+			N += sd->N*fabsf(average(sc->weight));
 		}
 	}
 
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 977ceac12ea..11657003259 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -263,6 +263,7 @@ typedef enum ShaderEvalType {
 	/* data passes */
 	SHADER_EVAL_NORMAL,
 	SHADER_EVAL_UV,
+	SHADER_EVAL_ROUGHNESS,
 	SHADER_EVAL_DIFFUSE_COLOR,
 	SHADER_EVAL_GLOSSY_COLOR,
 	SHADER_EVAL_TRANSMISSION_COLOR,