Refactored shadowmapping.

- Made shadow bias size independent, so it will remain when changing light or camera size.
- Implemented normal offset bias, which greatly enhances quality.
- Added transmission to subsurface scattering
- Reimplemented shadow filter modes

Closes #17260

4 files changed, 400 insertions, 100 deletions

diff --git a/servers/rendering/rasterizer_rd/shaders/blur.glsl b/servers/rendering/rasterizer_rd/shaders/blur.glsl
index 87c20ebaef..5dfdc614a4 100644
--- a/servers/rendering/rasterizer_rd/shaders/blur.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/blur.glsl
@@ -285,6 +285,13 @@ void main() {
 	frag_color = color;
 #endif
 
+#ifdef MODE_LINEARIZE_DEPTH_COPY
+	float depth = texture(source_color, uv_interp, 0.0).r;
+	depth = depth * 2.0 - 1.0;
+	depth = 2.0 * blur.camera_z_near * blur.camera_z_far / (blur.camera_z_far + blur.camera_z_near - depth * (blur.camera_z_far - blur.camera_z_near));
+	frag_color = vec4(depth / blur.camera_z_far);
+#endif
+
 #ifdef MODE_SSAO_MERGE
 	vec4 color = texture(source_color, uv_interp, 0.0);
 	float ssao = texture(source_ssao, uv_interp, 0.0).r;
diff --git a/servers/rendering/rasterizer_rd/shaders/copy.glsl b/servers/rendering/rasterizer_rd/shaders/copy.glsl
index cbb9b546a3..2b541f2660 100644
--- a/servers/rendering/rasterizer_rd/shaders/copy.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/copy.glsl
@@ -57,6 +57,7 @@ void main() {
 	}
 
 	float depth = texture(source_cube, normal).r;
+	depth_buffer = depth;
 
 	// absolute values for direction cosines, bigger value equals closer to basis axis
 	vec3 unorm = abs(normal);
@@ -80,7 +81,7 @@ void main() {
 
 	depth = 2.0 * depth - 1.0;
 	float linear_depth = 2.0 * params.z_near * params.z_far / (params.z_far + params.z_near - depth * (params.z_far - params.z_near));
-	depth_buffer = (linear_depth * depth_fix + params.bias) / params.z_far;
+	depth_buffer = (linear_depth * depth_fix) / params.z_far;
 
 #endif
 }
diff --git a/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl b/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
index 955ae2e588..62ab188ddc 100644
--- a/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
@@ -244,19 +244,13 @@ VERTEX_SHADER_CODE
 
 	//for dual paraboloid shadow mapping, this is the fastest but least correct way, as it curves straight edges
 
-	vec3 vtx = vertex_interp + normalize(vertex_interp) * scene_data.z_offset;
+	vec3 vtx = vertex_interp;
 	float distance = length(vtx);
 	vtx = normalize(vtx);
 	vtx.xy /= 1.0 - vtx.z;
 	vtx.z = (distance / scene_data.z_far);
 	vtx.z = vtx.z * 2.0 - 1.0;
-
 	vertex_interp = vtx;
-#else
-
-	float z_ofs = scene_data.z_offset;
-	z_ofs += max(0.0, 1.0 - abs(normalize(normal_interp).z)) * scene_data.z_slope_scale;
-	vertex_interp.z -= z_ofs;
 
 #endif
 
@@ -267,6 +261,14 @@ VERTEX_SHADER_CODE
 #else
 	gl_Position = projection_matrix * vec4(vertex_interp, 1.0);
 #endif
+
+#ifdef MODE_RENDER_DEPTH
+	if (scene_data.pancake_shadows) {
+		if (gl_Position.z <= 0.00001) {
+			gl_Position.z = 0.00001;
+		}
+	}
+#endif
 }
 
 /* clang-format off */
@@ -315,6 +317,11 @@ layout(location = 8) in float dp_clip;
 #define world_normal_matrix instances.data[instance_index].normal_transform
 #define projection_matrix scene_data.projection_matrix
 
+#if defined(ENABLE_SSS) && defined(ENABLE_TRANSMITTANCE)
+//both required for transmittance to be enabled
+#define LIGHT_TRANSMITTANCE_USED
+#endif
+
 #ifdef USE_MATERIAL_UNIFORMS
 layout(set = 5, binding = 0, std140) uniform MaterialUniforms{
 	/* clang-format off */
@@ -434,9 +441,16 @@ vec3 F0(float metallic, float specular, vec3 albedo) {
 	return mix(vec3(dielectric), albedo, vec3(metallic));
 }
 
-void light_compute(vec3 N, vec3 L, vec3 V, vec3 light_color, vec3 attenuation, vec3 diffuse_color, float roughness, float metallic, float specular, float specular_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-		vec3 transmission,
+void light_compute(vec3 N, vec3 L, vec3 V, vec3 light_color, float attenuation, vec3 shadow_attenuation, vec3 diffuse_color, float roughness, float metallic, float specular, float specular_blob_intensity,
+#ifdef LIGHT_BACKLIGHT_USED
+		vec3 backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+		vec4 transmittance_color,
+		float transmittance_depth,
+		float transmittance_curve,
+		float transmittance_boost,
+		float transmittance_z,
 #endif
 #ifdef LIGHT_RIM_USED
 		float rim, float rim_tint,
@@ -538,16 +552,48 @@ LIGHT_SHADER_CODE
 		diffuse_brdf_NL = cNdotL * (1.0 / M_PI);
 #endif
 
-		diffuse_light += light_color * diffuse_color * diffuse_brdf_NL * attenuation;
+		diffuse_light += light_color * diffuse_color * shadow_attenuation * diffuse_brdf_NL * attenuation;
 
-#if defined(LIGHT_TRANSMISSION_USED)
-		diffuse_light += light_color * diffuse_color * (vec3(1.0 / M_PI) - diffuse_brdf_NL) * transmission * attenuation;
+#if defined(LIGHT_BACKLIGHT_USED)
+		diffuse_light += light_color * diffuse_color * (vec3(1.0 / M_PI) - diffuse_brdf_NL) * backlight * attenuation;
 #endif
 
 #if defined(LIGHT_RIM_USED)
 		float rim_light = pow(max(0.0, 1.0 - cNdotV), max(0.0, (1.0 - roughness) * 16.0));
 		diffuse_light += rim_light * rim * mix(vec3(1.0), diffuse_color, rim_tint) * light_color;
 #endif
+
+#ifdef LIGHT_TRANSMITTANCE_USED
+
+#ifdef SSS_MODE_SKIN
+
+		{
+			float scale = 8.25 / transmittance_depth;
+			float d = scale * abs(transmittance_z);
+			float dd = -d * d;
+			vec3 profile = vec3(0.233, 0.455, 0.649) * exp(dd / 0.0064) +
+						   vec3(0.1, 0.336, 0.344) * exp(dd / 0.0484) +
+						   vec3(0.118, 0.198, 0.0) * exp(dd / 0.187) +
+						   vec3(0.113, 0.007, 0.007) * exp(dd / 0.567) +
+						   vec3(0.358, 0.004, 0.0) * exp(dd / 1.99) +
+						   vec3(0.078, 0.0, 0.0) * exp(dd / 7.41);
+
+			diffuse_light += profile * transmittance_color.a * diffuse_color * light_color * clamp(transmittance_boost - NdotL, 0.0, 1.0) * (1.0 / M_PI) * attenuation;
+		}
+#else
+
+		if (transmittance_depth > 0.0) {
+			float fade = clamp(abs(transmittance_z / transmittance_depth), 0.0, 1.0);
+
+			fade = pow(max(0.0, 1.0 - fade), transmittance_curve);
+			fade *= clamp(transmittance_boost - NdotL, 0.0, 1.0);
+
+			diffuse_light += diffuse_color * transmittance_color.rgb * light_color * (1.0 / M_PI) * transmittance_color.a * fade * attenuation;
+		}
+
+#endif //SSS_MODE_SKIN
+
+#endif //LIGHT_TRANSMITTANCE_USED
 	}
 
 	if (roughness > 0.0) { // FIXME: roughness == 0 should not disable specular light entirely
@@ -562,7 +608,7 @@ LIGHT_SHADER_CODE
 		blinn *= (shininess + 8.0) * (1.0 / (8.0 * M_PI));
 		float intensity = blinn;
 
-		specular_light += light_color * intensity * specular_blob_intensity * attenuation;
+		specular_light += light_color * shadow_attenuation * intensity * specular_blob_intensity * attenuation;
 
 #elif defined(SPECULAR_PHONG)
 
@@ -573,7 +619,7 @@ LIGHT_SHADER_CODE
 		phong *= (shininess + 8.0) * (1.0 / (8.0 * M_PI));
 		float intensity = (phong) / max(4.0 * cNdotV * cNdotL, 0.75);
 
-		specular_light += light_color * intensity * specular_blob_intensity * attenuation;
+		specular_light += light_color * shadow_attenuation * intensity * specular_blob_intensity * attenuation;
 
 #elif defined(SPECULAR_TOON)
 
@@ -582,7 +628,7 @@ LIGHT_SHADER_CODE
 		float mid = 1.0 - roughness;
 		mid *= mid;
 		float intensity = smoothstep(mid - roughness * 0.5, mid + roughness * 0.5, RdotV) * mid;
-		diffuse_light += light_color * intensity * specular_blob_intensity * attenuation; // write to diffuse_light, as in toon shading you generally want no reflection
+		diffuse_light += light_color * shadow_attenuation * intensity * specular_blob_intensity * attenuation; // write to diffuse_light, as in toon shading you generally want no reflection
 
 #elif defined(SPECULAR_DISABLED)
 		// none..
@@ -613,7 +659,7 @@ LIGHT_SHADER_CODE
 
 		vec3 specular_brdf_NL = cNdotL * D * F * G;
 
-		specular_light += specular_brdf_NL * light_color * specular_blob_intensity * attenuation;
+		specular_light += specular_brdf_NL * light_color * shadow_attenuation * specular_blob_intensity * attenuation;
 #endif
 
 #if defined(LIGHT_CLEARCOAT_USED)
@@ -627,12 +673,12 @@ LIGHT_SHADER_CODE
 
 		float clearcoat_specular_brdf_NL = 0.25 * clearcoat * Gr * Fr * Dr * cNdotL;
 
-		specular_light += clearcoat_specular_brdf_NL * light_color * specular_blob_intensity * attenuation;
+		specular_light += clearcoat_specular_brdf_NL * light_color * shadow_attenuation * specular_blob_intensity * attenuation;
 #endif
 	}
 
 #ifdef USE_SHADOW_TO_OPACITY
-	alpha = min(alpha, clamp(1.0 - length(attenuation), 0.0, 1.0));
+	alpha = min(alpha, clamp(1.0 - length(shadow_attenuation * attenuation), 0.0, 1.0));
 #endif
 
 #endif //defined(USE_LIGHT_SHADER_CODE)
@@ -642,51 +688,54 @@ LIGHT_SHADER_CODE
 
 float sample_shadow(texture2D shadow, vec2 shadow_pixel_size, vec4 coord) {
 
-	//todo optimize
 	vec2 pos = coord.xy;
 	float depth = coord.z;
 
-#ifdef SHADOW_MODE_PCF_13
-
-	float avg = textureProj(shadow, vec4(pos, depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, -shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, -shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x * 2.0, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x * 2.0, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y * 2.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y * 2.0), depth, 1.0));
-	return avg * (1.0 / 13.0);
-#endif
-
-#ifdef SHADOW_MODE_PCF_5
-
-	float avg = textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, 0.0), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y), depth, 1.0));
-	avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y), depth, 1.0));
-	return avg * (1.0 / 5.0);
-
-#endif
-
-#if !defined(SHADOW_MODE_PCF_5) || !defined(SHADOW_MODE_PCF_13)
-
-	return textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
+	switch (scene_data.shadow_filter_mode) {
+		case SHADOW_MODE_NO_FILTER: {
+			return textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
+		};
+		case SHADOW_MODE_PCF5: {
+			float avg = textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y), depth, 1.0));
+			return avg * (1.0 / 5.0);
+		};
+		case SHADOW_MODE_PCF13: {
+
+			float avg = textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x, -shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x, -shadow_pixel_size.y), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(shadow_pixel_size.x * 2.0, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(-shadow_pixel_size.x * 2.0, 0.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, shadow_pixel_size.y * 2.0), depth, 1.0));
+			avg += textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos + vec2(0.0, -shadow_pixel_size.y * 2.0), depth, 1.0));
+			return avg * (1.0 / 13.0);
+		};
+	}
 
-#endif
+	return 0;
 }
 
 #endif //USE_NO_SHADOWS
 
 void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 albedo, float roughness, float metallic, float specular, float p_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-		vec3 transmission,
+#ifdef LIGHT_BACKLIGHT_USED
+		vec3 backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+		vec4 transmittance_color,
+		float transmittance_depth,
+		float transmittance_curve,
+		float transmittance_boost,
 #endif
 #ifdef LIGHT_RIM_USED
 		float rim, float rim_tint,
@@ -707,18 +756,33 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 a
 	float normalized_distance = light_length * lights.data[idx].inv_radius;
 	vec2 attenuation_energy = unpackHalf2x16(lights.data[idx].attenuation_energy);
 	float omni_attenuation = pow(max(1.0 - normalized_distance, 0.0), attenuation_energy.x);
-	vec3 light_attenuation = vec3(omni_attenuation);
+	float light_attenuation = omni_attenuation;
+	vec3 shadow_attenuation = vec3(1.0);
 	vec4 color_specular = unpackUnorm4x8(lights.data[idx].color_specular);
 	color_specular.rgb *= attenuation_energy.y;
 
+#ifdef LIGHT_TRANSMITTANCE_USED
+	float transmittance_z = transmittance_depth; //no transmittance by default
+#endif
+
 #ifndef USE_NO_SHADOWS
 	vec4 shadow_color_enabled = unpackUnorm4x8(lights.data[idx].shadow_color_enabled);
 	if (shadow_color_enabled.w > 0.5) {
 		// there is a shadowmap
 
-		vec4 splane = (lights.data[idx].shadow_matrix * vec4(vertex, 1.0));
-		float shadow_len = length(splane);
-		splane = normalize(splane);
+		vec4 v = vec4(vertex, 1.0);
+
+		vec4 splane = (lights.data[idx].shadow_matrix * v);
+		float shadow_len = length(splane.xyz);
+
+		{
+			vec3 nofs = normal_interp * lights.data[idx].shadow_normal_bias / lights.data[idx].inv_radius;
+			nofs *= (1.0 - max(0.0, dot(normalize(light_rel_vec), normalize(normal_interp))));
+			v.xyz += nofs;
+			splane = (lights.data[idx].shadow_matrix * v);
+		}
+
+		splane.xyz = normalize(splane.xyz);
 		vec4 clamp_rect = lights.data[idx].atlas_rect;
 
 		if (splane.z >= 0.0) {
@@ -728,24 +792,60 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 a
 			clamp_rect.y += clamp_rect.w;
 
 		} else {
-
 			splane.z = 1.0 - splane.z;
 		}
 
 		splane.xy /= splane.z;
+
 		splane.xy = splane.xy * 0.5 + 0.5;
-		splane.z = shadow_len * lights.data[idx].inv_radius;
+		splane.z = (shadow_len - lights.data[idx].shadow_bias) * lights.data[idx].inv_radius;
 		splane.xy = clamp_rect.xy + splane.xy * clamp_rect.zw;
 		splane.w = 1.0; //needed? i think it should be 1 already
 		float shadow = sample_shadow(shadow_atlas, scene_data.shadow_atlas_pixel_size, splane);
 
-		light_attenuation *= mix(shadow_color_enabled.rgb, vec3(1.0), shadow);
+#ifdef LIGHT_TRANSMITTANCE_USED
+		{
+
+			//redo shadowmapping, but shrink the model a bit to avoid arctifacts
+			splane = (lights.data[idx].shadow_matrix * vec4(vertex - normalize(normal_interp) * lights.data[idx].transmittance_bias, 1.0));
+
+			shadow_len = length(splane);
+			splane = normalize(splane);
+
+			if (splane.z >= 0.0) {
+
+				splane.z += 1.0;
+
+			} else {
+
+				splane.z = 1.0 - splane.z;
+			}
+
+			splane.xy /= splane.z;
+			splane.xy = splane.xy * 0.5 + 0.5;
+			splane.z = shadow_len * lights.data[idx].inv_radius;
+			splane.xy = clamp_rect.xy + splane.xy * clamp_rect.zw;
+			splane.w = 1.0; //needed? i think it should be 1 already
+
+			float shadow_z = textureLod(sampler2D(shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), splane.xy, 0.0).r;
+			transmittance_z = (splane.z - shadow_z) / lights.data[idx].inv_radius;
+		}
+#endif
+
+		shadow_attenuation = mix(shadow_color_enabled.rgb, vec3(1.0), shadow);
 	}
 #endif //USE_NO_SHADOWS
 
-	light_compute(normal, normalize(light_rel_vec), eye_vec, color_specular.rgb, light_attenuation, albedo, roughness, metallic, specular, color_specular.a * p_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-			transmission,
+	light_compute(normal, normalize(light_rel_vec), eye_vec, color_specular.rgb, light_attenuation, shadow_attenuation, albedo, roughness, metallic, specular, color_specular.a * p_blob_intensity,
+#ifdef LIGHT_BACKLIGHT_USED
+			backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+			transmittance_color,
+			transmittance_depth,
+			transmittance_curve,
+			transmittance_boost,
+			transmittance_z,
 #endif
 #ifdef LIGHT_RIM_USED
 			rim * omni_attenuation, rim_tint,
@@ -764,8 +864,14 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 a
 }
 
 void light_process_spot(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 albedo, float roughness, float metallic, float specular, float p_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-		vec3 transmission,
+#ifdef LIGHT_BACKLIGHT_USED
+		vec3 backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+		vec4 transmittance_color,
+		float transmittance_depth,
+		float transmittance_curve,
+		float transmittance_boost,
 #endif
 #ifdef LIGHT_RIM_USED
 		float rim, float rim_tint,
@@ -792,7 +898,8 @@ void light_process_spot(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 a
 	float scos = max(dot(-normalize(light_rel_vec), spot_dir), spot_att_angle.y);
 	float spot_rim = max(0.0001, (1.0 - scos) / (1.0 - spot_att_angle.y));
 	spot_attenuation *= 1.0 - pow(spot_rim, spot_att_angle.x);
-	vec3 light_attenuation = vec3(spot_attenuation);
+	float light_attenuation = spot_attenuation;
+	vec3 shadow_attenuation = vec3(1.0);
 	vec4 color_specular = unpackUnorm4x8(lights.data[idx].color_specular);
 	color_specular.rgb *= attenuation_energy.y;
 
@@ -801,22 +908,58 @@ void light_process_spot(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 a
 		//use projector texture
 	}
 	*/
+#ifdef LIGHT_TRANSMITTANCE_USED
+	float transmittance_z = transmittance_depth;
+#endif
+
 #ifndef USE_NO_SHADOWS
 	vec4 shadow_color_enabled = unpackUnorm4x8(lights.data[idx].shadow_color_enabled);
 	if (shadow_color_enabled.w > 0.5) {
 		//there is a shadowmap
-		vec4 splane = (lights.data[idx].shadow_matrix * vec4(vertex, 1.0));
+		vec4 v = vec4(vertex, 1.0);
+
+		v.xyz -= spot_dir * lights.data[idx].shadow_bias;
+
+		float depth_bias_scale = 1.0 / (max(0.0001, dot(spot_dir, -light_rel_vec) * lights.data[idx].inv_radius)); //the closer to the light origin, the more you have to offset to reach 1px in the map
+		vec3 normal_bias = normalize(normal_interp) * (1.0 - max(0.0, dot(spot_dir, -normalize(normal_interp)))) * lights.data[idx].shadow_normal_bias * depth_bias_scale;
+		normal_bias -= spot_dir * dot(spot_dir, normal_bias); //only XY, no Z
+		v.xyz += normal_bias;
+
+		vec4 splane = (lights.data[idx].shadow_matrix * v);
 		splane /= splane.w;
+		splane.z = dot(spot_dir, v.xyz - lights.data[idx].position) * lights.data[idx].inv_radius;
 		float shadow = sample_shadow(shadow_atlas, scene_data.shadow_atlas_pixel_size, splane);
 
-		light_attenuation *= mix(shadow_color_enabled.rgb, vec3(1.0), shadow);
+		shadow_attenuation = mix(shadow_color_enabled.rgb, vec3(1.0), shadow);
+
+#ifdef LIGHT_TRANSMITTANCE_USED
+		{
+
+			splane = (lights.data[idx].shadow_matrix * vec4(vertex - normalize(normal_interp) * lights.data[idx].transmittance_bias, 1.0));
+			splane /= splane.w;
+
+			float shadow_z = textureLod(sampler2D(shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), splane.xy, 0.0).r;
+			//reconstruct depth
+			shadow_z / lights.data[idx].inv_radius;
+			//distance to light plane
+			float z = dot(spot_dir, -light_rel_vec);
+			transmittance_z = z - shadow_z;
+		}
+#endif //LIGHT_TRANSMITTANCE_USED
 	}
 
 #endif //USE_NO_SHADOWS
 
-	light_compute(normal, normalize(light_rel_vec), eye_vec, color_specular.rgb, light_attenuation, albedo, roughness, metallic, specular, color_specular.a * p_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-			transmission,
+	light_compute(normal, normalize(light_rel_vec), eye_vec, color_specular.rgb, light_attenuation, shadow_attenuation, albedo, roughness, metallic, specular, color_specular.a * p_blob_intensity,
+#ifdef LIGHT_BACKLIGHT_USED
+			backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+			transmittance_color,
+			transmittance_depth,
+			transmittance_curve,
+			transmittance_boost,
+			transmittance_z,
 #endif
 #ifdef LIGHT_RIM_USED
 			rim * spot_attenuation, rim_tint,
@@ -1185,7 +1328,11 @@ void main() {
 	vec3 vertex = vertex_interp;
 	vec3 view = -normalize(vertex_interp);
 	vec3 albedo = vec3(1.0);
-	vec3 transmission = vec3(0.0);
+	vec3 backlight = vec3(0.0);
+	vec4 transmittance_color = vec4(0.0);
+	float transmittance_depth = 0.0;
+	float transmittance_curve = 1.0;
+	float transmittance_boost = 0.0;
 	float metallic = 0.0;
 	float specular = 0.5;
 	vec3 emission = vec3(0.0);
@@ -1254,6 +1401,14 @@ FRAGMENT_SHADER_CODE
 		/* clang-format on */
 	}
 
+#if defined(LIGHT_TRANSMITTANCE_USED)
+#ifdef SSS_MODE_SKIN
+	transmittance_color.a = sss_strength;
+#else
+	transmittance_color.a *= sss_strength;
+#endif
+#endif
+
 #if !defined(USE_SHADOW_TO_OPACITY)
 
 #if defined(ALPHA_SCISSOR_USED)
@@ -1462,21 +1617,109 @@ FRAGMENT_SHADER_CODE
 				continue; //not masked
 			}
 
-			vec3 light_attenuation = vec3(1.0);
+			vec3 shadow_attenuation = vec3(1.0);
+
+#ifdef LIGHT_TRANSMITTANCE_USED
+			float transmittance_z = transmittance_depth;
+#endif
 
 			if (directional_lights.data[i].shadow_enabled) {
 				float depth_z = -vertex.z;
 
 				vec4 pssm_coord;
+				vec3 shadow_color = vec3(0.0);
+				vec3 light_dir = directional_lights.data[i].direction;
+
+#define BIAS_FUNC(m_var, m_idx)                                                                                                                                       \
+	m_var.xyz += light_dir * directional_lights.data[i].shadow_bias[m_idx];                                                                                           \
+	vec3 normal_bias = normalize(normal_interp) * (1.0 - max(0.0, dot(light_dir, -normalize(normal_interp)))) * directional_lights.data[i].shadow_normal_bias[m_idx]; \
+	normal_bias -= light_dir * dot(light_dir, normal_bias);                                                                                                           \
+	m_var.xyz += normal_bias;
 
 				if (depth_z < directional_lights.data[i].shadow_split_offsets.x) {
-					pssm_coord = (directional_lights.data[i].shadow_matrix1 * vec4(vertex, 1.0));
+					vec4 v = vec4(vertex, 1.0);
+
+					BIAS_FUNC(v, 0)
+
+					pssm_coord = (directional_lights.data[i].shadow_matrix1 * v);
+					shadow_color = directional_lights.data[i].shadow_color1.rgb;
+#ifdef LIGHT_TRANSMITTANCE_USED
+					{
+						vec4 trans_vertex = vec4(vertex - normalize(normal_interp) * directional_lights.data[i].shadow_transmittance_bias.x, 1.0);
+						vec4 trans_coord = directional_lights.data[i].shadow_matrix1 * trans_vertex;
+						trans_coord /= trans_coord.w;
+
+						float shadow_z = textureLod(sampler2D(directional_shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), trans_coord.xy, 0.0).r;
+						shadow_z *= directional_lights.data[i].shadow_transmittance_z_scale.x;
+						float z = trans_coord.z * directional_lights.data[i].shadow_transmittance_z_scale.x;
+
+						transmittance_z = z - shadow_z;
+					}
+#endif
 				} else if (depth_z < directional_lights.data[i].shadow_split_offsets.y) {
-					pssm_coord = (directional_lights.data[i].shadow_matrix2 * vec4(vertex, 1.0));
+
+					vec4 v = vec4(vertex, 1.0);
+
+					BIAS_FUNC(v, 1)
+
+					pssm_coord = (directional_lights.data[i].shadow_matrix2 * v);
+					shadow_color = directional_lights.data[i].shadow_color2.rgb;
+#ifdef LIGHT_TRANSMITTANCE_USED
+					{
+						vec4 trans_vertex = vec4(vertex - normalize(normal_interp) * directional_lights.data[i].shadow_transmittance_bias.y, 1.0);
+						vec4 trans_coord = directional_lights.data[i].shadow_matrix2 * trans_vertex;
+						trans_coord /= trans_coord.w;
+
+						float shadow_z = textureLod(sampler2D(directional_shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), trans_coord.xy, 0.0).r;
+						shadow_z *= directional_lights.data[i].shadow_transmittance_z_scale.y;
+						float z = trans_coord.z * directional_lights.data[i].shadow_transmittance_z_scale.y;
+
+						transmittance_z = z - shadow_z;
+					}
+#endif
 				} else if (depth_z < directional_lights.data[i].shadow_split_offsets.z) {
-					pssm_coord = (directional_lights.data[i].shadow_matrix3 * vec4(vertex, 1.0));
+
+					vec4 v = vec4(vertex, 1.0);
+
+					BIAS_FUNC(v, 2)
+
+					pssm_coord = (directional_lights.data[i].shadow_matrix3 * v);
+					shadow_color = directional_lights.data[i].shadow_color3.rgb;
+#ifdef LIGHT_TRANSMITTANCE_USED
+					{
+						vec4 trans_vertex = vec4(vertex - normalize(normal_interp) * directional_lights.data[i].shadow_transmittance_bias.z, 1.0);
+						vec4 trans_coord = directional_lights.data[i].shadow_matrix3 * trans_vertex;
+						trans_coord /= trans_coord.w;
+
+						float shadow_z = textureLod(sampler2D(directional_shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), trans_coord.xy, 0.0).r;
+						shadow_z *= directional_lights.data[i].shadow_transmittance_z_scale.z;
+						float z = trans_coord.z * directional_lights.data[i].shadow_transmittance_z_scale.z;
+
+						transmittance_z = z - shadow_z;
+					}
+#endif
+
 				} else {
-					pssm_coord = (directional_lights.data[i].shadow_matrix4 * vec4(vertex, 1.0));
+
+					vec4 v = vec4(vertex, 1.0);
+
+					BIAS_FUNC(v, 3)
+
+					pssm_coord = (directional_lights.data[i].shadow_matrix4 * v);
+					shadow_color = directional_lights.data[i].shadow_color4.rgb;
+#ifdef LIGHT_TRANSMITTANCE_USED
+					{
+						vec4 trans_vertex = vec4(vertex - normalize(normal_interp) * directional_lights.data[i].shadow_transmittance_bias.w, 1.0);
+						vec4 trans_coord = directional_lights.data[i].shadow_matrix4 * trans_vertex;
+						trans_coord /= trans_coord.w;
+
+						float shadow_z = textureLod(sampler2D(directional_shadow_atlas, material_samplers[SAMPLER_LINEAR_CLAMP]), trans_coord.xy, 0.0).r;
+						shadow_z *= directional_lights.data[i].shadow_transmittance_z_scale.w;
+						float z = trans_coord.z * directional_lights.data[i].shadow_transmittance_z_scale.w;
+
+						transmittance_z = z - shadow_z;
+					}
+#endif
 				}
 
 				pssm_coord /= pssm_coord.w;
@@ -1485,17 +1728,27 @@ FRAGMENT_SHADER_CODE
 
 				if (directional_lights.data[i].blend_splits) {
 
+					vec3 shadow_color_blend = vec3(0.0);
 					float pssm_blend;
 
 					if (depth_z < directional_lights.data[i].shadow_split_offsets.x) {
-						pssm_coord = (directional_lights.data[i].shadow_matrix2 * vec4(vertex, 1.0));
+						vec4 v = vec4(vertex, 1.0);
+						BIAS_FUNC(v, 1)
+						pssm_coord = (directional_lights.data[i].shadow_matrix2 * v);
 						pssm_blend = smoothstep(0.0, directional_lights.data[i].shadow_split_offsets.x, depth_z);
+						shadow_color_blend = directional_lights.data[i].shadow_color2.rgb;
 					} else if (depth_z < directional_lights.data[i].shadow_split_offsets.y) {
-						pssm_coord = (directional_lights.data[i].shadow_matrix3 * vec4(vertex, 1.0));
+						vec4 v = vec4(vertex, 1.0);
+						BIAS_FUNC(v, 2)
+						pssm_coord = (directional_lights.data[i].shadow_matrix3 * v);
 						pssm_blend = smoothstep(directional_lights.data[i].shadow_split_offsets.x, directional_lights.data[i].shadow_split_offsets.y, depth_z);
+						shadow_color_blend = directional_lights.data[i].shadow_color3.rgb;
 					} else if (depth_z < directional_lights.data[i].shadow_split_offsets.z) {
-						pssm_coord = (directional_lights.data[i].shadow_matrix4 * vec4(vertex, 1.0));
+						vec4 v = vec4(vertex, 1.0);
+						BIAS_FUNC(v, 3)
+						pssm_coord = (directional_lights.data[i].shadow_matrix4 * v);
 						pssm_blend = smoothstep(directional_lights.data[i].shadow_split_offsets.y, directional_lights.data[i].shadow_split_offsets.z, depth_z);
+						shadow_color_blend = directional_lights.data[i].shadow_color4.rgb;
 					} else {
 						pssm_blend = 0.0; //if no blend, same coord will be used (divide by z will result in same value, and already cached)
 					}
@@ -1504,16 +1757,26 @@ FRAGMENT_SHADER_CODE
 
 					float shadow2 = sample_shadow(directional_shadow_atlas, scene_data.directional_shadow_pixel_size, pssm_coord);
 					shadow = mix(shadow, shadow2, pssm_blend);
+					shadow_color = mix(shadow_color, shadow_color_blend, pssm_blend);
 				}
 
 				shadow = mix(shadow, 1.0, smoothstep(directional_lights.data[i].fade_from, directional_lights.data[i].fade_to, vertex.z)); //done with negative values for performance
 
-				light_attenuation = mix(directional_lights.data[i].shadow_color, vec3(1.0), shadow);
+				shadow_attenuation = mix(shadow_color, vec3(1.0), shadow);
+
+#undef BIAS_FUNC
 			}
 
-			light_compute(normal, directional_lights.data[i].direction, normalize(view), directional_lights.data[i].color * directional_lights.data[i].energy, light_attenuation, albedo, roughness, metallic, specular, directional_lights.data[i].specular * specular_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-					transmission,
+			light_compute(normal, directional_lights.data[i].direction, normalize(view), directional_lights.data[i].color * directional_lights.data[i].energy, 1.0, shadow_attenuation, albedo, roughness, metallic, specular, directional_lights.data[i].specular * specular_blob_intensity,
+#ifdef LIGHT_BACKLIGHT_USED
+					backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+					transmittance_color,
+					transmittance_depth,
+					transmittance_curve,
+					transmittance_boost,
+					transmittance_z,
 #endif
 #ifdef LIGHT_RIM_USED
 					rim, rim_tint,
@@ -1546,8 +1809,14 @@ FRAGMENT_SHADER_CODE
 			}
 
 			light_process_omni(light_index, vertex, view, normal, albedo, roughness, metallic, specular, specular_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-					transmission,
+#ifdef LIGHT_BACKLIGHT_USED
+					backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+					transmittance_color,
+					transmittance_depth,
+					transmittance_curve,
+					transmittance_boost,
 #endif
 #ifdef LIGHT_RIM_USED
 					rim,
@@ -1579,8 +1848,14 @@ FRAGMENT_SHADER_CODE
 			}
 
 			light_process_spot(light_index, vertex, view, normal, albedo, roughness, metallic, specular, specular_blob_intensity,
-#ifdef LIGHT_TRANSMISSION_USED
-					transmission,
+#ifdef LIGHT_BACKLIGHT_USED
+					backlight,
+#endif
+#ifdef LIGHT_TRANSMITTANCE_USED
+					transmittance_color,
+					transmittance_depth,
+					transmittance_curve,
+					transmittance_boost,
 #endif
 #ifdef LIGHT_RIM_USED
 					rim,
diff --git a/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl b/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
index baef1e060f..e3f1e650ed 100644
--- a/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
@@ -22,6 +22,10 @@ draw_call;
 #define SAMPLER_NEAREST_WITH_MIPMAPS_ANISOTROPIC_REPEAT 10
 #define SAMPLER_LINEAR_WITH_MIPMAPS_ANISOTROPIC_REPEAT 11
 
+#define SHADOW_MODE_NO_FILTER 0
+#define SHADOW_MODE_PCF5 1
+#define SHADOW_MODE_PCF13 2
+
 layout(set = 0, binding = 1) uniform sampler material_samplers[12];
 
 layout(set = 0, binding = 2) uniform sampler shadow_sampler;
@@ -37,13 +41,12 @@ layout(set = 0, binding = 3, std140) uniform SceneData {
 	vec2 viewport_size;
 	vec2 screen_pixel_size;
 
-	//used for shadow mapping only
-	float z_offset;
-	float z_slope_scale;
-
 	float time;
 	float reflection_multiplier; // one normally, zero when rendering reflections
 
+	bool pancake_shadows;
+	uint shadow_filter_mode;
+
 	vec4 ambient_light_color_energy;
 
 	float ambient_color_sky_mix;
@@ -134,7 +137,7 @@ layout(set = 0, binding = 4, std430) buffer Instances {
 }
 instances;
 
-struct LightData { //this structure needs to be 128 bits
+struct LightData { //this structure needs to be as packed as possible
 	vec3 position;
 	float inv_radius;
 	vec3 direction;
@@ -143,12 +146,16 @@ struct LightData { //this structure needs to be 128 bits
 	uint cone_attenuation_angle; // attenuation and angle, (16bit float)
 	uint mask;
 	uint shadow_color_enabled; //shadow rgb color, a>0.5 enabled (8bit unorm)
-	vec4 atlas_rect; //used for shadow atlas uv on omni, and for projection atlas on spot
+	vec4 atlas_rect; // used for spot
 	mat4 shadow_matrix;
+	float shadow_bias;
+	float shadow_normal_bias;
+	float transmittance_bias;
+	uint pad;
 };
 
-layout(set = 0, binding = 5, std140) uniform Lights {
-	LightData data[MAX_LIGHT_DATA_STRUCTS];
+layout(set = 0, binding = 5, std430) buffer Lights {
+	LightData data[];
 }
 lights;
 
@@ -174,17 +181,27 @@ struct DirectionalLightData {
 	float energy;
 	vec3 color;
 	float specular;
-	vec3 shadow_color;
 	uint mask;
+	uint pad0;
+	uint pad1;
+	uint pad2;
 	bool blend_splits;
 	bool shadow_enabled;
 	float fade_from;
 	float fade_to;
+	vec4 shadow_bias;
+	vec4 shadow_normal_bias;
+	vec4 shadow_transmittance_bias;
+	vec4 shadow_transmittance_z_scale;
 	vec4 shadow_split_offsets;
 	mat4 shadow_matrix1;
 	mat4 shadow_matrix2;
 	mat4 shadow_matrix3;
 	mat4 shadow_matrix4;
+	vec4 shadow_color1;
+	vec4 shadow_color2;
+	vec4 shadow_color3;
+	vec4 shadow_color4;
 };
 
 layout(set = 0, binding = 7, std140) uniform DirectionalLights {