Use Filament specular models and parametrization

5 files changed, 163 insertions, 132 deletions

diff --git a/servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp b/servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp
index 7987a98b0e..24be451e78 100644
--- a/servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp
+++ b/servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp
@@ -557,7 +557,7 @@ void SceneShaderForwardClustered::init(RendererStorageRD *p_storage, const Strin
 		actions.renames["RIM"] = "rim";
 		actions.renames["RIM_TINT"] = "rim_tint";
 		actions.renames["CLEARCOAT"] = "clearcoat";
-		actions.renames["CLEARCOAT_GLOSS"] = "clearcoat_gloss";
+		actions.renames["CLEARCOAT_ROUGHNESS"] = "clearcoat_roughness";
 		actions.renames["ANISOTROPY"] = "anisotropy";
 		actions.renames["ANISOTROPY_FLOW"] = "anisotropy_flow";
 		actions.renames["SSS_STRENGTH"] = "sss_strength";
@@ -607,7 +607,7 @@ void SceneShaderForwardClustered::init(RendererStorageRD *p_storage, const Strin
 		actions.usage_defines["RIM"] = "#define LIGHT_RIM_USED\n";
 		actions.usage_defines["RIM_TINT"] = "@RIM";
 		actions.usage_defines["CLEARCOAT"] = "#define LIGHT_CLEARCOAT_USED\n";
-		actions.usage_defines["CLEARCOAT_GLOSS"] = "@CLEARCOAT";
+		actions.usage_defines["CLEARCOAT_ROUGHNESS"] = "@CLEARCOAT";
 		actions.usage_defines["ANISOTROPY"] = "#define LIGHT_ANISOTROPY_USED\n";
 		actions.usage_defines["ANISOTROPY_FLOW"] = "@ANISOTROPY";
 		actions.usage_defines["AO"] = "#define AO_USED\n";
@@ -663,20 +663,12 @@ void SceneShaderForwardClustered::init(RendererStorageRD *p_storage, const Strin
 
 		actions.render_mode_defines["sss_mode_skin"] = "#define SSS_MODE_SKIN\n";
 
-		bool force_blinn = GLOBAL_GET("rendering/shading/overrides/force_blinn_over_ggx");
-
-		if (!force_blinn) {
-			actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_SCHLICK_GGX\n";
-		} else {
-			actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_BLINN\n";
-		}
+		actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_SCHLICK_GGX\n";
 
 		actions.custom_samplers["SCREEN_TEXTURE"] = "material_samplers[3]"; // linear filter with mipmaps
 		actions.custom_samplers["DEPTH_TEXTURE"] = "material_samplers[3]";
 		actions.custom_samplers["NORMAL_ROUGHNESS_TEXTURE"] = "material_samplers[1]"; // linear filter
 
-		actions.render_mode_defines["specular_blinn"] = "#define SPECULAR_BLINN\n";
-		actions.render_mode_defines["specular_phong"] = "#define SPECULAR_PHONG\n";
 		actions.render_mode_defines["specular_toon"] = "#define SPECULAR_TOON\n";
 		actions.render_mode_defines["specular_disabled"] = "#define SPECULAR_DISABLED\n";
 		actions.render_mode_defines["shadows_disabled"] = "#define SHADOWS_DISABLED\n";
diff --git a/servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp b/servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp
index 0b99948063..34b2fa9440 100644
--- a/servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp
+++ b/servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp
@@ -545,7 +545,7 @@ void SceneShaderForwardMobile::init(RendererStorageRD *p_storage, const String p
 		actions.renames["RIM"] = "rim";
 		actions.renames["RIM_TINT"] = "rim_tint";
 		actions.renames["CLEARCOAT"] = "clearcoat";
-		actions.renames["CLEARCOAT_GLOSS"] = "clearcoat_gloss";
+		actions.renames["CLEARCOAT_ROUGHNESS"] = "clearcoat_roughness";
 		actions.renames["ANISOTROPY"] = "anisotropy";
 		actions.renames["ANISOTROPY_FLOW"] = "anisotropy_flow";
 		actions.renames["SSS_STRENGTH"] = "sss_strength";
@@ -594,7 +594,7 @@ void SceneShaderForwardMobile::init(RendererStorageRD *p_storage, const String p
 		actions.usage_defines["RIM"] = "#define LIGHT_RIM_USED\n";
 		actions.usage_defines["RIM_TINT"] = "@RIM";
 		actions.usage_defines["CLEARCOAT"] = "#define LIGHT_CLEARCOAT_USED\n";
-		actions.usage_defines["CLEARCOAT_GLOSS"] = "@CLEARCOAT";
+		actions.usage_defines["CLEARCOAT_ROUGHNESS"] = "@CLEARCOAT";
 		actions.usage_defines["ANISOTROPY"] = "#define LIGHT_ANISOTROPY_USED\n";
 		actions.usage_defines["ANISOTROPY_FLOW"] = "@ANISOTROPY";
 		actions.usage_defines["AO"] = "#define AO_USED\n";
@@ -649,15 +649,8 @@ void SceneShaderForwardMobile::init(RendererStorageRD *p_storage, const String p
 
 		actions.render_mode_defines["sss_mode_skin"] = "#define SSS_MODE_SKIN\n";
 
-		bool force_blinn = GLOBAL_GET("rendering/shading/overrides/force_blinn_over_ggx");
-		if (!force_blinn) {
-			actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_SCHLICK_GGX\n";
-		} else {
-			actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_BLINN\n";
-		}
+		actions.render_mode_defines["specular_schlick_ggx"] = "#define SPECULAR_SCHLICK_GGX\n";
 
-		actions.render_mode_defines["specular_blinn"] = "#define SPECULAR_BLINN\n";
-		actions.render_mode_defines["specular_phong"] = "#define SPECULAR_PHONG\n";
 		actions.render_mode_defines["specular_toon"] = "#define SPECULAR_TOON\n";
 		actions.render_mode_defines["specular_disabled"] = "#define SPECULAR_DISABLED\n";
 		actions.render_mode_defines["shadows_disabled"] = "#define SHADOWS_DISABLED\n";
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
index 5d65b00bee..a8648fc96a 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
@@ -478,8 +478,8 @@ layout(location = 0) out vec4 frag_color;
 
 #if !defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
-/* Make a default specular mode SPECULAR_SCHLICK_GGX. */
-#if !defined(SPECULAR_DISABLED) && !defined(SPECULAR_SCHLICK_GGX) && !defined(SPECULAR_BLINN) && !defined(SPECULAR_PHONG) && !defined(SPECULAR_TOON)
+// Default to SPECULAR_SCHLICK_GGX.
+#if !defined(SPECULAR_DISABLED) && !defined(SPECULAR_SCHLICK_GGX) && !defined(SPECULAR_TOON)
 #define SPECULAR_SCHLICK_GGX
 #endif
 
@@ -589,7 +589,7 @@ void main() {
 	float rim = 0.0;
 	float rim_tint = 0.0;
 	float clearcoat = 0.0;
-	float clearcoat_gloss = 0.0;
+	float clearcoat_roughness = 0.0;
 	float anisotropy = 0.0;
 	vec2 anisotropy_flow = vec2(1.0, 0.0);
 	vec4 fog = vec4(0.0);
@@ -912,7 +912,17 @@ void main() {
 #if !defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
 	if (scene_data.use_reflection_cubemap) {
+#ifdef LIGHT_ANISOTROPY_USED
+		// https://google.github.io/filament/Filament.html#lighting/imagebasedlights/anisotropy
+		vec3 anisotropic_direction = anisotropy >= 0.0 ? binormal : tangent;
+		vec3 anisotropic_tangent = cross(anisotropic_direction, view);
+		vec3 anisotropic_normal = cross(anisotropic_tangent, anisotropic_direction);
+		vec3 bent_normal = normalize(mix(normal, anisotropic_normal, abs(anisotropy) * clamp(5.0 * roughness, 0.0, 1.0)));
+		vec3 ref_vec = reflect(-view, bent_normal);
+#else
 		vec3 ref_vec = reflect(-view, normal);
+#endif
+
 		float horizon = min(1.0 + dot(ref_vec, normal), 1.0);
 		ref_vec = scene_data.radiance_inverse_xform * ref_vec;
 #ifdef USE_RADIANCE_CUBEMAP_ARRAY
@@ -954,6 +964,36 @@ void main() {
 #if defined(CUSTOM_IRRADIANCE_USED)
 	ambient_light = mix(ambient_light, custom_irradiance.rgb, custom_irradiance.a);
 #endif
+
+#ifdef LIGHT_CLEARCOAT_USED
+
+	if (scene_data.use_reflection_cubemap) {
+		vec3 n = normalize(normal_interp); // We want to use geometric normal, not normal_map
+		float NoV = max(dot(n, view), 0.0001);
+		vec3 ref_vec = reflect(-view, n);
+		// The clear coat layer assumes an IOR of 1.5 (4% reflectance)
+		float Fc = clearcoat * (0.04 + 0.96 * SchlickFresnel(NoV));
+		float attenuation = 1.0 - Fc;
+		ambient_light *= attenuation;
+		specular_light *= attenuation;
+
+		float horizon = min(1.0 + dot(ref_vec, normal), 1.0);
+		ref_vec = scene_data.radiance_inverse_xform * ref_vec;
+		float roughness_lod = mix(0.001, 0.1, clearcoat_roughness) * MAX_ROUGHNESS_LOD;
+#ifdef USE_RADIANCE_CUBEMAP_ARRAY
+
+		float lod, blend;
+		blend = modf(roughness_lod, lod);
+		vec3 clearcoat_light = texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(ref_vec, lod)).rgb;
+		clearcoat_light = mix(clearcoat_light, texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(ref_vec, lod + 1)).rgb, blend);
+
+#else
+		vec3 clearcoat_light = textureLod(samplerCube(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), ref_vec, roughness_lod).rgb;
+
+#endif //USE_RADIANCE_CUBEMAP_ARRAY
+		specular_light += clearcoat_light * horizon * horizon * Fc * scene_data.ambient_light_color_energy.a;
+	}
+#endif
 #endif //!defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
 	//radiance
@@ -1202,8 +1242,16 @@ void main() {
 				if (!bool(reflections.data[reflection_index].mask & instances.data[instance_index].layer_mask)) {
 					continue; //not masked
 				}
-
-				reflection_process(reflection_index, vertex, normal, roughness, ambient_light, specular_light, ambient_accum, reflection_accum);
+#ifdef LIGHT_ANISOTROPY_USED
+				// https://google.github.io/filament/Filament.html#lighting/imagebasedlights/anisotropy
+				vec3 anisotropic_direction = anisotropy >= 0.0 ? binormal : tangent;
+				vec3 anisotropic_tangent = cross(anisotropic_direction, view);
+				vec3 anisotropic_normal = cross(anisotropic_tangent, anisotropic_direction);
+				vec3 bent_normal = normalize(mix(normal, anisotropic_normal, abs(anisotropy) * clamp(5.0 * roughness, 0.0, 1.0)));
+#else
+				vec3 bent_normal = normal;
+#endif
+				reflection_process(reflection_index, vertex, bent_normal, roughness, ambient_light, specular_light, ambient_accum, reflection_accum);
 			}
 		}
 
@@ -1555,10 +1603,11 @@ void main() {
 					rim, rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-					clearcoat, clearcoat_gloss,
+					clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
-					binormal, tangent, anisotropy,
+					binormal,
+					tangent, anisotropy,
 #endif
 					diffuse_light,
 					specular_light);
@@ -1626,7 +1675,7 @@ void main() {
 						rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-						clearcoat, clearcoat_gloss,
+						clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 						tangent, binormal, anisotropy,
@@ -1698,10 +1747,11 @@ void main() {
 						rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-						clearcoat, clearcoat_gloss,
+						clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
-						tangent, binormal, anisotropy,
+						tangent,
+						binormal, anisotropy,
 #endif
 						diffuse_light, specular_light);
 			}
@@ -1904,7 +1954,7 @@ void main() {
 	frag_color = vec4(albedo, alpha);
 #else
 	frag_color = vec4(emission + ambient_light + diffuse_light + specular_light, alpha);
-	//frag_color = vec4(1.0);
+//frag_color = vec4(1.0);
 #endif //USE_NO_SHADING
 
 	// Draw "fixed" fog before volumetric fog to ensure volumetric fog can appear in front of the sky.
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
index 16f77fb91a..cf2e835b04 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
@@ -1,55 +1,29 @@
 // Functions related to lighting
 
-// This returns the G_GGX function divided by 2 cos_theta_m, where in practice cos_theta_m is either N.L or N.V.
-// We're dividing this factor off because the overall term we'll end up looks like
-// (see, for example, the first unnumbered equation in B. Burley, "Physically Based Shading at Disney", SIGGRAPH 2012):
-//
-//   F(L.V) D(N.H) G(N.L) G(N.V) / (4 N.L N.V)
-//
-// We're basically regouping this as
-//
-//   F(L.V) D(N.H) [G(N.L)/(2 N.L)] [G(N.V) / (2 N.V)]
-//
-// and thus, this function implements the [G(N.m)/(2 N.m)] part with m = L or V.
-//
-// The contents of the D and G (G1) functions (GGX) are taken from
-// E. Heitz, "Understanding the Masking-Shadowing Function in Microfacet-Based BRDFs", J. Comp. Graph. Tech. 3 (2) (2014).
-// Eqns 71-72 and 85-86 (see also Eqns 43 and 80).
-
-float G_GGX_2cos(float cos_theta_m, float alpha) {
-	// Schlick's approximation
-	// C. Schlick, "An Inexpensive BRDF Model for Physically-based Rendering", Computer Graphics Forum. 13 (3): 233 (1994)
-	// Eq. (19), although see Heitz (2014) the about the problems with his derivation.
-	// It nevertheless approximates GGX well with k = alpha/2.
-	float k = 0.5 * alpha;
-	return 0.5 / (cos_theta_m * (1.0 - k) + k);
-
-	// float cos2 = cos_theta_m * cos_theta_m;
-	// float sin2 = (1.0 - cos2);
-	// return 1.0 / (cos_theta_m + sqrt(cos2 + alpha * alpha * sin2));
-}
-
 float D_GGX(float cos_theta_m, float alpha) {
 	float alpha2 = alpha * alpha;
 	float d = 1.0 + (alpha2 - 1.0) * cos_theta_m * cos_theta_m;
 	return alpha2 / (M_PI * d * d);
 }
 
-float G_GGX_anisotropic_2cos(float cos_theta_m, float alpha_x, float alpha_y, float cos_phi, float sin_phi) {
-	float cos2 = cos_theta_m * cos_theta_m;
-	float sin2 = (1.0 - cos2);
-	float s_x = alpha_x * cos_phi;
-	float s_y = alpha_y * sin_phi;
-	return 1.0 / max(cos_theta_m + sqrt(cos2 + (s_x * s_x + s_y * s_y) * sin2), 0.001);
+// From Earl Hammon, Jr. "PBR Diffuse Lighting for GGX+Smith Microsurfaces" https://www.gdcvault.com/play/1024478/PBR-Diffuse-Lighting-for-GGX
+float V_GGX(float NdotL, float NdotV, float alpha) {
+	return 0.5 / mix(2.0 * NdotL * NdotV, NdotL + NdotV, alpha);
 }
 
 float D_GGX_anisotropic(float cos_theta_m, float alpha_x, float alpha_y, float cos_phi, float sin_phi) {
-	float cos2 = cos_theta_m * cos_theta_m;
-	float sin2 = (1.0 - cos2);
-	float r_x = cos_phi / alpha_x;
-	float r_y = sin_phi / alpha_y;
-	float d = cos2 + sin2 * (r_x * r_x + r_y * r_y);
-	return 1.0 / max(M_PI * alpha_x * alpha_y * d * d, 0.001);
+	float alpha2 = alpha_x * alpha_y;
+	highp vec3 v = vec3(alpha_y * cos_phi, alpha_x * sin_phi, alpha2 * cos_theta_m);
+	highp float v2 = dot(v, v);
+	float w2 = alpha2 / v2;
+	float D = alpha2 * w2 * w2 * (1.0 / M_PI);
+	return D;
+}
+
+float V_GGX_anisotropic(float alpha_x, float alpha_y, float TdotV, float TdotL, float BdotV, float BdotL, float NdotV, float NdotL) {
+	float Lambda_V = NdotL * length(vec3(alpha_x * TdotV, alpha_y * BdotV, NdotV));
+	float Lambda_L = NdotV * length(vec3(alpha_x * TdotL, alpha_y * BdotL, NdotL));
+	return 0.5 / (Lambda_V + Lambda_L);
 }
 
 float SchlickFresnel(float u) {
@@ -58,14 +32,6 @@ float SchlickFresnel(float u) {
 	return m2 * m2 * m; // pow(m,5)
 }
 
-float GTR1(float NdotH, float a) {
-	if (a >= 1.0)
-		return 1.0 / M_PI;
-	float a2 = a * a;
-	float t = 1.0 + (a2 - 1.0) * NdotH * NdotH;
-	return (a2 - 1.0) / (M_PI * log(a2) * t);
-}
-
 vec3 F0(float metallic, float specular, vec3 albedo) {
 	float dielectric = 0.16 * specular * specular;
 	// use albedo * metallic as colored specular reflectance at 0 angle for metallic materials;
@@ -87,7 +53,7 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, float atte
 		float rim, float rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-		float clearcoat, float clearcoat_gloss,
+		float clearcoat, float clearcoat_roughness, vec3 vertex_normal,
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 		vec3 B, vec3 T, float anisotropy,
@@ -115,11 +81,11 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, float atte
 	float NdotV = dot(N, V);
 	float cNdotV = max(NdotV, 0.0);
 
-#if defined(DIFFUSE_BURLEY) || defined(SPECULAR_BLINN) || defined(SPECULAR_SCHLICK_GGX) || defined(LIGHT_CLEARCOAT_USED)
+#if defined(DIFFUSE_BURLEY) || defined(SPECULAR_SCHLICK_GGX) || defined(LIGHT_CLEARCOAT_USED)
 	vec3 H = normalize(V + L);
 #endif
 
-#if defined(SPECULAR_BLINN) || defined(SPECULAR_SCHLICK_GGX) || defined(LIGHT_CLEARCOAT_USED)
+#if defined(SPECULAR_SCHLICK_GGX)
 	float cNdotH = clamp(A + dot(N, H), 0.0, 1.0);
 #endif
 
@@ -203,26 +169,7 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, float atte
 
 		// D
 
-#if defined(SPECULAR_BLINN)
-
-		//normalized blinn
-		float shininess = exp2(15.0 * (1.0 - roughness) + 1.0) * 0.25;
-		float blinn = pow(cNdotH, shininess);
-		blinn *= (shininess + 2.0) * (1.0 / (8.0 * M_PI));
-
-		specular_light += light_color * attenuation * specular_amount * blinn * f0 * orms_unpacked.w;
-
-#elif defined(SPECULAR_PHONG)
-
-		vec3 R = normalize(-reflect(L, N));
-		float cRdotV = clamp(A + dot(R, V), 0.0, 1.0);
-		float shininess = exp2(15.0 * (1.0 - roughness) + 1.0) * 0.25;
-		float phong = pow(cRdotV, shininess);
-		phong *= (shininess + 1.0) * (1.0 / (8.0 * M_PI));
-
-		specular_light += light_color * attenuation * specular_amount * phong * f0 * orms_unpacked.w;
-
-#elif defined(SPECULAR_TOON)
+#if defined(SPECULAR_TOON)
 
 		vec3 R = normalize(-reflect(L, N));
 		float RdotV = dot(R, V);
@@ -236,24 +183,21 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, float atte
 
 #elif defined(SPECULAR_SCHLICK_GGX)
 		// shlick+ggx as default
-
+		float alpha_ggx = roughness * roughness;
 #if defined(LIGHT_ANISOTROPY_USED)
 
-		float alpha_ggx = roughness * roughness;
 		float aspect = sqrt(1.0 - anisotropy * 0.9);
 		float ax = alpha_ggx / aspect;
 		float ay = alpha_ggx * aspect;
 		float XdotH = dot(T, H);
 		float YdotH = dot(B, H);
 		float D = D_GGX_anisotropic(cNdotH, ax, ay, XdotH, YdotH);
-		float G = G_GGX_anisotropic_2cos(cNdotL, ax, ay, XdotH, YdotH) * G_GGX_anisotropic_2cos(cNdotV, ax, ay, XdotH, YdotH);
-
-#else
-		float alpha_ggx = roughness * roughness;
+		float G = V_GGX_anisotropic(ax, ay, dot(T, V), dot(T, L), dot(B, V), dot(B, L), cNdotV, cNdotL);
+#else // LIGHT_ANISOTROPY_USED
 		float D = D_GGX(cNdotH, alpha_ggx);
-		float G = G_GGX_2cos(cNdotL, alpha_ggx) * G_GGX_2cos(cNdotV, alpha_ggx);
-#endif
-		// F
+		float G = V_GGX(cNdotL, cNdotV, alpha_ggx);
+#endif // LIGHT_ANISOTROPY_USED
+	   // F
 		float cLdotH5 = SchlickFresnel(cLdotH);
 		vec3 F = mix(vec3(cLdotH5), vec3(1.0), f0);
 
@@ -263,18 +207,23 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, float atte
 #endif
 
 #if defined(LIGHT_CLEARCOAT_USED)
+		// Clearcoat ignores normal_map, use vertex normal instead
+		float ccNdotL = max(min(A + dot(vertex_normal, L), 1.0), 0.0);
+		float ccNdotH = clamp(A + dot(vertex_normal, H), 0.0, 1.0);
+		float ccNdotV = max(dot(vertex_normal, V), 0.0);
 
 #if !defined(SPECULAR_SCHLICK_GGX)
 		float cLdotH5 = SchlickFresnel(cLdotH);
 #endif
-		float Dr = GTR1(cNdotH, mix(.1, .001, clearcoat_gloss));
+		float Dr = D_GGX(ccNdotH, mix(0.001, 0.1, clearcoat_roughness));
+		float Gr = 0.25 / (cLdotH * cLdotH);
 		float Fr = mix(.04, 1.0, cLdotH5);
-		float Gr = G_GGX_2cos(cNdotL, .25) * G_GGX_2cos(cNdotV, .25);
-
-		float clearcoat_specular_brdf_NL = 0.25 * clearcoat * Gr * Fr * Dr * cNdotL;
+		float clearcoat_specular_brdf_NL = clearcoat * Gr * Fr * Dr * cNdotL;
 
 		specular_light += clearcoat_specular_brdf_NL * light_color * attenuation * specular_amount;
-#endif
+		// TODO: Clearcoat adds light to the scene right now (it is non-energy conserving), both diffuse and specular need to be scaled by (1.0 - FR)
+		// but to do so we need to rearrange this entire function
+#endif // LIGHT_CLEARCOAT_USED
 	}
 
 #ifdef USE_SHADOW_TO_OPACITY
@@ -587,7 +536,7 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 v
 		float rim, float rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-		float clearcoat, float clearcoat_gloss,
+		float clearcoat, float clearcoat_roughness, vec3 vertex_normal,
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 		vec3 binormal, vec3 tangent, float anisotropy,
@@ -711,7 +660,7 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 v
 			rim * omni_attenuation, rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-			clearcoat, clearcoat_gloss,
+			clearcoat, clearcoat_roughness, vertex_normal,
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 			binormal, tangent, anisotropy,
@@ -827,7 +776,7 @@ void light_process_spot(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 v
 		float rim, float rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-		float clearcoat, float clearcoat_gloss,
+		float clearcoat, float clearcoat_roughness, vec3 vertex_normal,
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 		vec3 binormal, vec3 tangent, float anisotropy,
@@ -912,7 +861,7 @@ void light_process_spot(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 v
 			rim * spot_attenuation, rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-			clearcoat, clearcoat_gloss,
+			clearcoat, clearcoat_roughness, vertex_normal,
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 			binormal, tangent, anisotropy,
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
index 4d6a3b5864..a1cf1d3c04 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
@@ -511,8 +511,8 @@ layout(location = 0) out mediump vec4 frag_color;
 
 #if !defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
-/* Make a default specular mode SPECULAR_SCHLICK_GGX. */
-#if !defined(SPECULAR_DISABLED) && !defined(SPECULAR_SCHLICK_GGX) && !defined(SPECULAR_BLINN) && !defined(SPECULAR_PHONG) && !defined(SPECULAR_TOON)
+// Default to SPECULAR_SCHLICK_GGX.
+#if !defined(SPECULAR_DISABLED) && !defined(SPECULAR_SCHLICK_GGX) && !defined(SPECULAR_TOON)
 #define SPECULAR_SCHLICK_GGX
 #endif
 
@@ -596,7 +596,7 @@ void main() {
 	float rim = 0.0;
 	float rim_tint = 0.0;
 	float clearcoat = 0.0;
-	float clearcoat_gloss = 0.0;
+	float clearcoat_roughness = 0.0;
 	float anisotropy = 0.0;
 	vec2 anisotropy_flow = vec2(1.0, 0.0);
 	vec4 fog = vec4(0.0);
@@ -874,7 +874,16 @@ void main() {
 #if !defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
 	if (scene_data.use_reflection_cubemap) {
+#ifdef LIGHT_ANISOTROPY_USED
+		// https://google.github.io/filament/Filament.html#lighting/imagebasedlights/anisotropy
+		vec3 anisotropic_direction = anisotropy >= 0.0 ? binormal : tangent;
+		vec3 anisotropic_tangent = cross(anisotropic_direction, view);
+		vec3 anisotropic_normal = cross(anisotropic_tangent, anisotropic_direction);
+		vec3 bent_normal = normalize(mix(normal, anisotropic_normal, abs(anisotropy) * clamp(5.0 * roughness, 0.0, 1.0)));
+		vec3 ref_vec = reflect(-view, bent_normal);
+#else
 		vec3 ref_vec = reflect(-view, normal);
+#endif
 		float horizon = min(1.0 + dot(ref_vec, normal), 1.0);
 		ref_vec = scene_data.radiance_inverse_xform * ref_vec;
 #ifdef USE_RADIANCE_CUBEMAP_ARRAY
@@ -917,7 +926,35 @@ void main() {
 #if defined(CUSTOM_IRRADIANCE_USED)
 	ambient_light = mix(specular_light, custom_irradiance.rgb, custom_irradiance.a);
 #endif // CUSTOM_IRRADIANCE_USED
+#ifdef LIGHT_CLEARCOAT_USED
+
+	if (scene_data.use_reflection_cubemap) {
+		vec3 n = normalize(normal_interp); // We want to use geometric normal, not normal_map
+		float NoV = max(dot(n, view), 0.0001);
+		vec3 ref_vec = reflect(-view, n);
+		// The clear coat layer assumes an IOR of 1.5 (4% reflectance)
+		float Fc = clearcoat * (0.04 + 0.96 * SchlickFresnel(NoV));
+		float attenuation = 1.0 - Fc;
+		ambient_light *= attenuation;
+		specular_light *= attenuation;
 
+		float horizon = min(1.0 + dot(ref_vec, normal), 1.0);
+		ref_vec = scene_data.radiance_inverse_xform * ref_vec;
+		float roughness_lod = mix(0.001, 0.1, clearcoat_roughness) * MAX_ROUGHNESS_LOD;
+#ifdef USE_RADIANCE_CUBEMAP_ARRAY
+
+		float lod, blend;
+		blend = modf(roughness_lod, lod);
+		vec3 clearcoat_light = texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(ref_vec, lod)).rgb;
+		clearcoat_light = mix(clearcoat_light, texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(ref_vec, lod + 1)).rgb, blend);
+
+#else
+		vec3 clearcoat_light = textureLod(samplerCube(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), ref_vec, roughness_lod).rgb;
+
+#endif //USE_RADIANCE_CUBEMAP_ARRAY
+		specular_light += clearcoat_light * horizon * horizon * Fc * scene_data.ambient_light_color_energy.a;
+	}
+#endif
 #endif //!defined(MODE_RENDER_DEPTH) && !defined(MODE_UNSHADED)
 
 	//radiance
@@ -1002,8 +1039,16 @@ void main() {
 			if (reflection_index == 0xFF) {
 				break;
 			}
-
-			reflection_process(reflection_index, vertex, normal, roughness, ambient_light, specular_light, ambient_accum, reflection_accum);
+#ifdef LIGHT_ANISOTROPY_USED
+			// https://google.github.io/filament/Filament.html#lighting/imagebasedlights/anisotropy
+			vec3 anisotropic_direction = anisotropy >= 0.0 ? binormal : tangent;
+			vec3 anisotropic_tangent = cross(anisotropic_direction, view);
+			vec3 anisotropic_normal = cross(anisotropic_tangent, anisotropic_direction);
+			vec3 bent_normal = normalize(mix(normal, anisotropic_normal, abs(anisotropy) * clamp(5.0 * roughness, 0.0, 1.0)));
+#else
+			vec3 bent_normal = normal;
+#endif
+			reflection_process(reflection_index, vertex, bent_normal, roughness, ambient_light, specular_light, ambient_accum, reflection_accum);
 		}
 
 		if (reflection_accum.a > 0.0) {
@@ -1368,7 +1413,7 @@ void main() {
 					rim, rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-					clearcoat, clearcoat_gloss,
+					clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
 					binormal, tangent, anisotropy,
@@ -1415,10 +1460,11 @@ void main() {
 					rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-					clearcoat, clearcoat_gloss,
+					clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
-					tangent, binormal, anisotropy,
+					tangent,
+					binormal, anisotropy,
 #endif
 					diffuse_light, specular_light);
 		}
@@ -1459,10 +1505,11 @@ void main() {
 					rim_tint,
 #endif
 #ifdef LIGHT_CLEARCOAT_USED
-					clearcoat, clearcoat_gloss,
+					clearcoat, clearcoat_roughness, normalize(normal_interp),
 #endif
 #ifdef LIGHT_ANISOTROPY_USED
-					tangent, binormal, anisotropy,
+					tangent,
+					binormal, anisotropy,
 #endif
 					diffuse_light, specular_light);
 		}