Fix T51408: Cycles - Principled BSDF Shader - Transparency is not working as expected

Renamed the "Transparency" input of the Principled BSDF to
"Transmission" and "Refraction Roughness" to "Transmission Roughness".

intern/cycles/kernel/shaders/node_principled_bsdf.osl

@@ -34,17 +34,17 @@ shader node_principled_bsdf(
 	float Clearcoat = 0.0,
 	float ClearcoatGloss = 1.0,
 	float IOR = 1.45,
-	float Transparency = 0.0,
+	float Transmission = 0.0,
-	float RefractionRoughness = 0.0,
+	float TransmissionRoughness = 0.0,
 	normal Normal = N,
 	normal ClearcoatNormal = N,
 	normal Tangent = normalize(dPdu),
 	output closure color BSDF = 0)
 {
 	float f = max(IOR, 1e-5);
-	float diffuse_weight = (1.0 - clamp(Metallic, 0.0, 1.0)) * (1.0 - clamp(Transparency, 0.0, 1.0));
+	float diffuse_weight = (1.0 - clamp(Metallic, 0.0, 1.0)) * (1.0 - clamp(Transmission, 0.0, 1.0));
-	float transp = clamp(Transparency, 0.0, 1.0) * (1.0 - clamp(Metallic, 0.0, 1.0));
+	float final_transmission = clamp(Transmission, 0.0, 1.0) * (1.0 - clamp(Metallic, 0.0, 1.0));
-	float specular_weight = (1.0 - transp);
+	float specular_weight = (1.0 - final_transmission);
 
 	vector T = Tangent;
 
@@ -90,7 +90,7 @@ shader node_principled_bsdf(
 		}
 	}
 
-	if (transp > 1e-5) {
+	if (final_transmission > 1e-5) {
 		color Cspec0 = BaseColor * SpecularTint + color(1.0, 1.0, 1.0) * (1.0 - SpecularTint);
 		float eta = backfacing() ? 1.0 / f : f;
 
@@ -102,14 +102,14 @@ shader node_principled_bsdf(
 			if (Roughness <= 1e-2)
 				refl_roughness = 0.0;
 
-			float refraction_roughness = refl_roughness;
+			float transmission_roughness = refl_roughness;
 			if (distribution == "GGX")
-				refraction_roughness = 1.0 - (1.0 - refl_roughness) * (1.0 - RefractionRoughness);
+				transmission_roughness = 1.0 - (1.0 - refl_roughness) * (1.0 - TransmissionRoughness);
 
-			BSDF = BSDF + transp * (Fr * microfacet_ggx_fresnel(Normal, refl_roughness * refl_roughness, eta, BaseColor, Cspec0) +
+			BSDF = BSDF + final_transmission * (Fr * microfacet_ggx_fresnel(Normal, refl_roughness * refl_roughness, eta, BaseColor, Cspec0) +
-			       (1.0 - Fr) * BaseColor * microfacet_ggx_refraction(Normal, refraction_roughness * refraction_roughness, eta));
+			       (1.0 - Fr) * BaseColor * microfacet_ggx_refraction(Normal, transmission_roughness * transmission_roughness, eta));
 		} else {
-			BSDF = BSDF + transp * microfacet_multi_ggx_glass_fresnel(Normal, Roughness * Roughness, eta, BaseColor, Cspec0);
+			BSDF = BSDF + final_transmission * microfacet_multi_ggx_glass_fresnel(Normal, Roughness * Roughness, eta, BaseColor, Cspec0);
 		}
 	}
 

intern/cycles/kernel/svm/svm_closure.h

@@ -79,14 +79,14 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 #ifdef __PRINCIPLED__
 		case CLOSURE_BSDF_PRINCIPLED_ID: {
 			uint specular_offset, roughness_offset, specular_tint_offset, anisotropic_offset, sheen_offset,
-				sheen_tint_offset, clearcoat_offset, clearcoat_gloss_offset, eta_offset, transparency_offset,
+				sheen_tint_offset, clearcoat_offset, clearcoat_gloss_offset, eta_offset, transmission_offset,
-				anisotropic_rotation_offset, refraction_roughness_offset;
+				anisotropic_rotation_offset, transmission_roughness_offset;
 			uint4 data_node2 = read_node(kg, offset);
 
 			float3 T = stack_load_float3(stack, data_node.y);
 			decode_node_uchar4(data_node.z, &specular_offset, &roughness_offset, &specular_tint_offset, &anisotropic_offset);
 			decode_node_uchar4(data_node.w, &sheen_offset, &sheen_tint_offset, &clearcoat_offset, &clearcoat_gloss_offset);
-			decode_node_uchar4(data_node2.x, &eta_offset, &transparency_offset, &anisotropic_rotation_offset, &refraction_roughness_offset);
+			decode_node_uchar4(data_node2.x, &eta_offset, &transmission_offset, &anisotropic_rotation_offset, &transmission_roughness_offset);
 
 			// get Disney principled parameters
 			float metallic = param1;
@@ -99,9 +99,9 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 			float sheen_tint = stack_load_float(stack, sheen_tint_offset);
 			float clearcoat = stack_load_float(stack, clearcoat_offset);
 			float clearcoat_gloss = stack_load_float(stack, clearcoat_gloss_offset);
-			float transparency = stack_load_float(stack, transparency_offset);
+			float transmission = stack_load_float(stack, transmission_offset);
 			float anisotropic_rotation = stack_load_float(stack, anisotropic_rotation_offset);
-			float refraction_roughness = stack_load_float(stack, refraction_roughness_offset);
+			float transmission_roughness = stack_load_float(stack, transmission_roughness_offset);
 			float eta = fmaxf(stack_load_float(stack, eta_offset), 1e-5f);
 
 			ClosureType distribution = stack_valid(data_node2.y) ? (ClosureType) data_node2.y : CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID;
@@ -118,10 +118,10 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 			float fresnel = fresnel_dielectric_cos(cosNO, ior);
 
 			// calculate weights of the diffuse and specular part
-			float diffuse_weight = (1.0f - saturate(metallic)) * (1.0f - saturate(transparency));
+			float diffuse_weight = (1.0f - saturate(metallic)) * (1.0f - saturate(transmission));
 			
-			float transp = saturate(transparency) * (1.0f - saturate(metallic));
+			float final_transmission = saturate(transmission) * (1.0f - saturate(metallic));
-			float specular_weight = (1.0f - transp);
+			float specular_weight = (1.0f - final_transmission);
 
 			// get the base color
 			uint4 data_base_color = read_node(kg, offset);
@@ -300,8 +300,8 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 #ifdef __CAUSTICS_TRICKS__
 			if(kernel_data.integrator.caustics_reflective || kernel_data.integrator.caustics_refractive || (path_flag & PATH_RAY_DIFFUSE) == 0) {
 #endif
-				if(transp > CLOSURE_WEIGHT_CUTOFF) {
+				if(final_transmission > CLOSURE_WEIGHT_CUTOFF) {
-					float3 glass_weight = weight * transp;
+					float3 glass_weight = weight * final_transmission;
 					float3 cspec0 = base_color * specular_tint + make_float3(1.0f, 1.0f, 1.0f) * (1.0f - specular_tint);
 
 					if(roughness <= 5e-2f || distribution == CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID) { /* use single-scatter GGX */
@@ -342,12 +342,12 @@ ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *
 								bsdf->N = N;
 
 								if(distribution == CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID)
-									refraction_roughness = 1.0f - (1.0f - refl_roughness) * (1.0f - refraction_roughness);
+									transmission_roughness = 1.0f - (1.0f - refl_roughness) * (1.0f - transmission_roughness);
 								else
-									refraction_roughness = refl_roughness;
+									transmission_roughness = refl_roughness;
 
-								bsdf->alpha_x = refraction_roughness * refraction_roughness;
+								bsdf->alpha_x = transmission_roughness * transmission_roughness;
-								bsdf->alpha_y = refraction_roughness * refraction_roughness;
+								bsdf->alpha_y = transmission_roughness * transmission_roughness;
 								bsdf->ior = ior;
 
 								/* setup bsdf */

intern/cycles/render/nodes.cpp

@@ -2316,8 +2316,8 @@ NODE_DEFINE(PrincipledBsdfNode)
 	SOCKET_IN_FLOAT(clearcoat, "Clearcoat", 0.0f);
 	SOCKET_IN_FLOAT(clearcoat_gloss, "Clearcoat Gloss", 0.0f);
 	SOCKET_IN_FLOAT(ior, "IOR", 0.0f);
-	SOCKET_IN_FLOAT(transparency, "Transparency", 0.0f);
+	SOCKET_IN_FLOAT(transmission, "Transmission", 0.0f);
-	SOCKET_IN_FLOAT(refraction_roughness, "Refraction Roughness", 0.0f);
+	SOCKET_IN_FLOAT(transmission_roughness, "Transmission Roughness", 0.0f);
 	SOCKET_IN_FLOAT(anisotropic_rotation, "Anisotropic Rotation", 0.0f);
 	SOCKET_IN_NORMAL(normal, "Normal", make_float3(0.0f, 0.0f, 0.0f), SocketType::LINK_NORMAL);
 	SOCKET_IN_NORMAL(clearcoat_normal, "Clearcoat Normal", make_float3(0.0f, 0.0f, 0.0f), SocketType::LINK_NORMAL);
@@ -2352,7 +2352,7 @@ void PrincipledBsdfNode::attributes(Shader *shader, AttributeRequestSet *attribu
 void PrincipledBsdfNode::compile(SVMCompiler& compiler, ShaderInput *p_metallic, ShaderInput *p_subsurface, ShaderInput *p_subsurface_radius,
 	ShaderInput *p_specular, ShaderInput *p_roughness, ShaderInput *p_specular_tint, ShaderInput *p_anisotropic,
 	ShaderInput *p_sheen, ShaderInput *p_sheen_tint, ShaderInput *p_clearcoat, ShaderInput *p_clearcoat_gloss,
-	ShaderInput *p_ior, ShaderInput *p_transparency, ShaderInput *p_anisotropic_rotation, ShaderInput *p_refraction_roughness)
+	ShaderInput *p_ior, ShaderInput *p_transmission, ShaderInput *p_anisotropic_rotation, ShaderInput *p_transmission_roughness)
 {
 	ShaderInput *base_color_in = input("Base Color");
 	ShaderInput *subsurface_color_in = input("Subsurface Color");
@@ -2376,8 +2376,8 @@ void PrincipledBsdfNode::compile(SVMCompiler& compiler, ShaderInput *p_metallic,
 	int clearcoat_offset = compiler.stack_assign(p_clearcoat);
 	int clearcoat_gloss_offset = compiler.stack_assign(p_clearcoat_gloss);
 	int ior_offset = compiler.stack_assign(p_ior);
-	int transparency_offset = compiler.stack_assign(p_transparency);
+	int transmission_offset = compiler.stack_assign(p_transmission);
-	int refraction_roughness_offset = compiler.stack_assign(p_refraction_roughness);
+	int transmission_roughness_offset = compiler.stack_assign(p_transmission_roughness);
 	int anisotropic_rotation_offset = compiler.stack_assign(p_anisotropic_rotation);
 	int subsurface_radius_offset = compiler.stack_assign(p_subsurface_radius);
 
@@ -2393,7 +2393,7 @@ void PrincipledBsdfNode::compile(SVMCompiler& compiler, ShaderInput *p_metallic,
 		compiler.encode_uchar4(specular_offset, roughness_offset, specular_tint_offset, anisotropic_offset),
 		compiler.encode_uchar4(sheen_offset, sheen_tint_offset, clearcoat_offset, clearcoat_gloss_offset));
 
-	compiler.add_node(compiler.encode_uchar4(ior_offset, transparency_offset, anisotropic_rotation_offset, refraction_roughness_offset),
+	compiler.add_node(compiler.encode_uchar4(ior_offset, transmission_offset, anisotropic_rotation_offset, transmission_roughness_offset),
 		distribution, SVM_STACK_INVALID, SVM_STACK_INVALID);
 
 	float3 bc_default = get_float3(base_color_in->socket_type);
@@ -2419,8 +2419,8 @@ void PrincipledBsdfNode::compile(SVMCompiler& compiler)
 {
 	compile(compiler, input("Metallic"), input("Subsurface"), input("Subsurface Radius"), input("Specular"),
 		input("Roughness"), input("Specular Tint"), input("Anisotropic"), input("Sheen"), input("Sheen Tint"),
-		input("Clearcoat"), input("Clearcoat Gloss"), input("IOR"), input("Transparency"),
+		input("Clearcoat"), input("Clearcoat Gloss"), input("IOR"), input("Transmission"),
-		input("Anisotropic Rotation"), input("Refraction Roughness"));
+		input("Anisotropic Rotation"), input("Transmission Roughness"));
 }
 
 void PrincipledBsdfNode::compile(OSLCompiler& compiler)

intern/cycles/render/nodes.h

@@ -378,13 +378,13 @@ public:
 	void compile(SVMCompiler& compiler, ShaderInput *metallic, ShaderInput *subsurface, ShaderInput *subsurface_radius,
 		ShaderInput *specular, ShaderInput *roughness, ShaderInput *specular_tint, ShaderInput *anisotropic,
 		ShaderInput *sheen, ShaderInput *sheen_tint, ShaderInput *clearcoat, ShaderInput *clearcoat_gloss,
-		ShaderInput *ior, ShaderInput *transparency, ShaderInput *anisotropic_rotation, ShaderInput *refraction_roughness);
+		ShaderInput *ior, ShaderInput *transmission, ShaderInput *anisotropic_rotation, ShaderInput *transmission_roughness);
 
 	float3 base_color;
 	float3 subsurface_color, subsurface_radius;
 	float metallic, subsurface, specular, roughness, specular_tint, anisotropic,
-		sheen, sheen_tint, clearcoat, clearcoat_gloss, ior, transparency,
+		sheen, sheen_tint, clearcoat, clearcoat_gloss, ior, transmission,
-		anisotropic_rotation, refraction_roughness;
+		anisotropic_rotation, transmission_roughness;
 	float3 normal, clearcoat_normal, tangent;
 	float surface_mix_weight;
 	ClosureType distribution, distribution_orig;

source/blender/gpu/shaders/gpu_shader_material.glsl

@@ -2621,7 +2621,7 @@ void node_bsdf_toon(vec4 color, float size, float tsmooth, vec3 N, out vec4 resu
 
 void node_bsdf_principled(vec4 base_color, float subsurface, vec3 subsurface_radius, vec4 subsurface_color, float metallic, float specular,
 	float specular_tint, float roughness, float anisotropic, float anisotropic_rotation, float sheen, float sheen_tint, float clearcoat,
-	float clearcoat_gloss, float ior, float transparency, float refraction_roughness, vec3 N, vec3 CN, vec3 T, vec3 I, out vec4 result)
+	float clearcoat_gloss, float ior, float transmission, float transmission_roughness, vec3 N, vec3 CN, vec3 T, vec3 I, out vec4 result)
 {
 	/* ambient light */
 	// TODO: set ambient light to an appropriate value

source/blender/nodes/shader/nodes/node_shader_bsdf_principled.c

@@ -45,8 +45,8 @@ static bNodeSocketTemplate sh_node_bsdf_principled_in[] = {
 	{	SOCK_FLOAT, 1, N_("Clearcoat"),				0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
 	{	SOCK_FLOAT, 1, N_("Clearcoat Gloss"),		1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
 	{	SOCK_FLOAT, 1, N_("IOR"),					1.45f, 0.0f, 0.0f, 0.0f, 0.0f, 1000.0f},
-	{	SOCK_FLOAT, 1, N_("Transparency"),			0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
+	{	SOCK_FLOAT, 1, N_("Transmission"),			0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
-	{	SOCK_FLOAT, 1, N_("Refraction Roughness"),	0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
+	{	SOCK_FLOAT, 1, N_("Transmission Roughness"),0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_FACTOR},
 	{	SOCK_VECTOR, 1, N_("Normal"),				0.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
 	{	SOCK_VECTOR, 1, N_("Clearcoat Normal"),		0.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
 	{	SOCK_VECTOR, 1, N_("Tangent"),				0.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
@@ -86,7 +86,7 @@ static void node_shader_update_principled(bNodeTree *UNUSED(ntree), bNode *node)
 	int distribution = node->custom1;
 
 	for (sock = node->inputs.first; sock; sock = sock->next) {
-		if (STREQ(sock->name, "Refraction Roughness")) {
+		if (STREQ(sock->name, "Transmission Roughness")) {
 			if (distribution == SHD_GLOSSY_GGX)
 				sock->flag &= ~SOCK_UNAVAIL;
 			else