Eevee: Fix non normalized Normals in BSDFs and Layer Weight

Although the normal was normalized when evaluating the lighting, the normal
is often used for other purpose. In this case using the non normalized
normal maybe the source of errors.

1 files changed, 27 insertions, 13 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 865fd85e2a9..06e797db8c4 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -1097,7 +1097,8 @@ vec3 principled_sheen(float NV, vec3 basecol_tint, float sheen_tint)
 #ifndef VOLUMETRICS
 void node_bsdf_diffuse(vec4 color, float roughness, vec3 N, out Closure result)
 {
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	N = normalize(N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.ssr_normal = normal_encode(vN, viewCameraVec);
 	eevee_closure_diffuse(N, color.rgb, 1.0, result.radiance);
@@ -1106,9 +1107,10 @@ void node_bsdf_diffuse(vec4 color, float roughness, vec3 N, out Closure result)
 
 void node_bsdf_glossy(vec4 color, float roughness, vec3 N, float ssr_id, out Closure result)
 {
+	N = normalize(N);
 	vec3 out_spec, ssr_spec;
 	eevee_closure_glossy(N, vec3(1.0), int(ssr_id), roughness, 1.0, out_spec, ssr_spec);
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec * color.rgb;
 	result.ssr_data = vec4(ssr_spec * color.rgb, roughness);
@@ -1125,13 +1127,14 @@ void node_bsdf_anisotropic(
 
 void node_bsdf_glass(vec4 color, float roughness, float ior, vec3 N, float ssr_id, out Closure result)
 {
+	N = normalize(N);
 	vec3 out_spec, out_refr, ssr_spec;
 	vec3 refr_color = (refractionDepth > 0.0) ? color.rgb * color.rgb : color.rgb; /* Simulate 2 transmission event */
 	eevee_closure_glass(N, vec3(1.0), int(ssr_id), roughness, 1.0, ior, out_spec, out_refr, ssr_spec);
 	out_refr *= refr_color;
 	out_spec *= color.rgb;
 	float fresnel = F_eta(ior, dot(N, cameraVec));
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = mix(out_refr, out_spec, fresnel);
 	result.ssr_data = vec4(ssr_spec * color.rgb * fresnel, roughness);
@@ -1150,6 +1153,7 @@ void node_bsdf_principled(
         float clearcoat_roughness, float ior, float transmission, float transmission_roughness, vec3 N, vec3 CN, vec3 T, vec3 I, float ssr_id,
         float sss_id, vec3 sss_scale, out Closure result)
 {
+	N = normalize(N);
 	ior = max(ior, 1e-5);
 	metallic = saturate(metallic);
 	transmission = saturate(transmission);
@@ -1184,7 +1188,7 @@ void node_bsdf_principled(
 	refr_color *= (refractionDepth > 0.0) ? refr_color : vec3(1.0); /* Simulate 2 transmission event */
 	out_refr *= refr_color * (1.0 - fresnel) * transmission;
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec + out_refr;
 	result.radiance += out_diff * out_sheen; /* Coarse approx. */
@@ -1212,6 +1216,7 @@ void node_bsdf_principled_dielectric(
         float clearcoat_roughness, float ior, float transmission, float transmission_roughness, vec3 N, vec3 CN, vec3 T, vec3 I, float ssr_id,
         float sss_id, vec3 sss_scale, out Closure result)
 {
+	N = normalize(N);
 	metallic = saturate(metallic);
 	float dielectric = 1.0 - metallic;
 
@@ -1224,7 +1229,7 @@ void node_bsdf_principled_dielectric(
 
 	eevee_closure_default(N, diffuse, f0, int(ssr_id), roughness, 1.0, out_diff, out_spec, ssr_spec);
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec + out_diff * (diffuse + out_sheen);
 	result.ssr_data = vec4(ssr_spec, roughness);
@@ -1238,11 +1243,12 @@ void node_bsdf_principled_metallic(
         float clearcoat_roughness, float ior, float transmission, float transmission_roughness, vec3 N, vec3 CN, vec3 T, vec3 I, float ssr_id,
         float sss_id, vec3 sss_scale, out Closure result)
 {
+	N = normalize(N);
 	vec3 out_spec, ssr_spec;
 
 	eevee_closure_glossy(N, base_color.rgb, int(ssr_id), roughness, 1.0, out_spec, ssr_spec);
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec;
 	result.ssr_data = vec4(ssr_spec, roughness);
@@ -1257,11 +1263,12 @@ void node_bsdf_principled_clearcoat(
         float sss_id, vec3 sss_scale, out Closure result)
 {
 	vec3 out_spec, ssr_spec;
+	N = normalize(N);
 
 	eevee_closure_clearcoat(N, base_color.rgb, int(ssr_id), roughness, CN, clearcoat * 0.25, clearcoat_roughness,
 	                        1.0, out_spec, ssr_spec);
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec;
 	result.ssr_data = vec4(ssr_spec, roughness);
@@ -1276,6 +1283,7 @@ void node_bsdf_principled_subsurface(
         float sss_id, vec3 sss_scale, out Closure result)
 {
 	metallic = saturate(metallic);
+	N = normalize(N);
 
 	vec3 diffuse, f0, out_diff, out_spec, out_trans, ssr_spec;
 	vec3 ctint = tint_from_color(base_color.rgb);
@@ -1291,7 +1299,7 @@ void node_bsdf_principled_subsurface(
 	eevee_closure_skin(N, mixed_ss_base_color, f0, int(ssr_id), roughness, 1.0, sss_scalef,
 	                   out_diff, out_trans, out_spec, ssr_spec);
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = out_spec;
 	result.ssr_data = vec4(ssr_spec, roughness);
@@ -1318,6 +1326,7 @@ void node_bsdf_principled_glass(
         float sss_id, vec3 sss_scale, out Closure result)
 {
 	ior = max(ior, 1e-5);
+	N = normalize(N);
 
 	vec3 f0, out_spec, out_refr, ssr_spec;
 	f0 = mix(vec3(1.0), base_color.rgb, specular_tint);
@@ -1333,7 +1342,7 @@ void node_bsdf_principled_glass(
 	out_spec *= spec_col;
 	ssr_spec *= spec_col * fresnel;
 
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.radiance = mix(out_refr, out_spec, fresnel);
 	result.ssr_data = vec4(ssr_spec, roughness);
@@ -1365,8 +1374,9 @@ void node_subsurface_scattering(
         out Closure result)
 {
 #if defined(USE_SSS)
+	N = normalize(N);
 	vec3 out_diff, out_trans;
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.ssr_data = vec4(0.0);
 	result.ssr_normal = normal_encode(vN, viewCameraVec);
@@ -1388,10 +1398,11 @@ void node_subsurface_scattering(
 
 void node_bsdf_refraction(vec4 color, float roughness, float ior, vec3 N, out Closure result)
 {
+	N = normalize(N);
 	vec3 out_refr;
 	color.rgb *= (refractionDepth > 0.0) ? color.rgb : vec3(1.0); /* Simulate 2 absorption event. */
 	eevee_closure_refraction(N, roughness, ior, out_refr);
-	vec3 vN = normalize(mat3(ViewMatrix) * N);
+	vec3 vN = mat3(ViewMatrix) * N;
 	result = CLOSURE_DEFAULT;
 	result.ssr_normal = normal_encode(vN, viewCameraVec);
 	result.radiance = out_refr * color.rgb;
@@ -1590,6 +1601,7 @@ void node_add_shader(Closure shader1, Closure shader2, out Closure shader)
 
 void node_fresnel(float ior, vec3 N, vec3 I, out float result)
 {
+	N = normalize(N);
 	/* handle perspective/orthographic */
 	vec3 I_view = (ProjectionMatrix[3][3] == 0.0) ? normalize(I) : vec3(0.0, 0.0, -1.0);
 
@@ -1601,6 +1613,8 @@ void node_fresnel(float ior, vec3 N, vec3 I, out float result)
 
 void node_layer_weight(float blend, vec3 N, vec3 I, out float fresnel, out float facing)
 {
+	N = normalize(N);
+
 	/* fresnel */
 	float eta = max(1.0 - blend, 0.00001);
 	vec3 I_view = (ProjectionMatrix[3][3] == 0.0) ? normalize(I) : vec3(0.0, 0.0, -1.0);
@@ -1723,7 +1737,7 @@ void node_tangentmap(vec4 attr_tangent, mat4 toworld, out vec3 tangent)
 
 void node_tangent(vec3 N, vec3 orco, mat4 objmat, mat4 toworld, out vec3 T)
 {
-	N = (toworld * vec4(N, 0.0)).xyz;
+	N = normalize(worldNormal);
 	T = (objmat * vec4(orco, 0.0)).xyz;
 	T = cross(N, normalize(cross(T, N)));
 }
@@ -1735,7 +1749,7 @@ void node_geometry(
         out float backfacing, out float pointiness)
 {
 	position = worldPosition;
-	normal = (toworld * vec4(N, 0.0)).xyz;
+	normal = normalize(worldNormal);
 	tangent_orco_z(orco, orco);
 	node_tangent(N, orco, objmat, toworld, tangent);
 	true_normal = normal;