Add a shadow opacity property to Light3D

This can be used to make shadows translucent for a specific light.

The light distance fade system also uses this to smoothly fade the shadow
when the light fade transition distance is greater than 0.

5 files changed, 17 insertions, 13 deletions

diff --git a/servers/rendering/renderer_rd/shaders/environment/volumetric_fog_process.glsl b/servers/rendering/renderer_rd/shaders/environment/volumetric_fog_process.glsl
index e74cfad65c..6f79b9e771 100644
--- a/servers/rendering/renderer_rd/shaders/environment/volumetric_fog_process.glsl
+++ b/servers/rendering/renderer_rd/shaders/environment/volumetric_fog_process.glsl
@@ -377,7 +377,7 @@ void main() {
 		for (uint i = 0; i < params.directional_light_count; i++) {
 			vec3 shadow_attenuation = vec3(1.0);
 
-			if (directional_lights.data[i].shadow_enabled) {
+			if (directional_lights.data[i].shadow_opacity > 0.001) {
 				float depth_z = -view_pos.z;
 
 				vec4 pssm_coord;
@@ -486,7 +486,7 @@ void main() {
 
 						vec3 light = omni_lights.data[light_index].color;
 
-						if (omni_lights.data[light_index].shadow_enabled) {
+						if (omni_lights.data[light_index].shadow_opacity > 0.001) {
 							//has shadow
 							vec4 uv_rect = omni_lights.data[light_index].atlas_rect;
 							vec2 flip_offset = omni_lights.data[light_index].direction.xy;
@@ -572,7 +572,7 @@ void main() {
 
 						vec3 light = spot_lights.data[light_index].color;
 
-						if (spot_lights.data[light_index].shadow_enabled) {
+						if (spot_lights.data[light_index].shadow_opacity > 0.001) {
 							//has shadow
 							vec4 uv_rect = spot_lights.data[light_index].atlas_rect;
 							vec2 flip_offset = spot_lights.data[light_index].direction.xy;
diff --git a/servers/rendering/renderer_rd/shaders/light_data_inc.glsl b/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
index 61c8488a05..799f7087b6 100644
--- a/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
@@ -15,7 +15,7 @@ struct LightData { //this structure needs to be as packed as possible
 	mediump float cone_attenuation;
 	mediump float cone_angle;
 	mediump float specular_amount;
-	bool shadow_enabled;
+	mediump float shadow_opacity;
 
 	highp vec4 atlas_rect; // rect in the shadow atlas
 	highp mat4 shadow_matrix;
@@ -60,7 +60,7 @@ struct DirectionalLightData {
 	highp float softshadow_angle;
 	highp float soft_shadow_scale;
 	bool blend_splits;
-	bool shadow_enabled;
+	mediump float shadow_opacity;
 	highp float fade_from;
 	highp float fade_to;
 	uvec2 pad;
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
index 22058b3a06..dff24b7144 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
@@ -1417,7 +1417,7 @@ void fragment_shader(in SceneData scene_data) {
 
 			float shadow = 1.0;
 
-			if (directional_lights.data[i].shadow_enabled) {
+			if (directional_lights.data[i].shadow_opacity > 0.001) {
 				float depth_z = -vertex.z;
 				vec3 light_dir = directional_lights.data[i].direction;
 				vec3 base_normal_bias = normalize(normal_interp) * (1.0 - max(0.0, dot(light_dir, -normalize(normal_interp))));
@@ -1626,7 +1626,7 @@ void fragment_shader(in SceneData scene_data) {
 #ifdef LIGHT_TRANSMITTANCE_USED
 			float transmittance_z = transmittance_depth;
 
-			if (directional_lights.data[i].shadow_enabled) {
+			if (directional_lights.data[i].shadow_opacity > 0.001) {
 				float depth_z = -vertex.z;
 
 				if (depth_z < directional_lights.data[i].shadow_split_offsets.x) {
@@ -1681,6 +1681,8 @@ void fragment_shader(in SceneData scene_data) {
 			} else {
 				shadow = float(shadow1 >> ((i - 4) * 8) & 0xFF) / 255.0;
 			}
+
+			shadow = shadow * directional_lights.data[i].shadow_opacity + 1.0 - directional_lights.data[i].shadow_opacity;
 #endif
 
 			blur_shadow(shadow);
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 e27c81eaea..50a13de11a 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
@@ -395,7 +395,7 @@ float get_omni_attenuation(float distance, float inv_range, float decay) {
 
 float light_process_omni_shadow(uint idx, vec3 vertex, vec3 normal) {
 #ifndef SHADOWS_DISABLED
-	if (omni_lights.data[idx].shadow_enabled) {
+	if (omni_lights.data[idx].shadow_opacity > 0.001) {
 		// there is a shadowmap
 		vec2 texel_size = scene_data_block.data.shadow_atlas_pixel_size;
 		vec4 base_uv_rect = omni_lights.data[idx].atlas_rect;
@@ -498,6 +498,7 @@ float light_process_omni_shadow(uint idx, vec3 vertex, vec3 normal) {
 				}
 
 				shadow /= float(sc_penumbra_shadow_samples);
+				shadow = mix(1.0, shadow, omni_lights.data[idx].shadow_opacity);
 
 			} else {
 				//no blockers found, so no shadow
@@ -516,7 +517,7 @@ float light_process_omni_shadow(uint idx, vec3 vertex, vec3 normal) {
 			vec2 pos = shadow_sample.xy / shadow_sample.z;
 			float depth = shadow_len - omni_lights.data[idx].shadow_bias;
 			depth *= omni_lights.data[idx].inv_radius;
-			shadow = sample_omni_pcf_shadow(shadow_atlas, omni_lights.data[idx].soft_shadow_scale / shadow_sample.z, pos, uv_rect, flip_offset, depth);
+			shadow = mix(1.0, sample_omni_pcf_shadow(shadow_atlas, omni_lights.data[idx].soft_shadow_scale / shadow_sample.z, pos, uv_rect, flip_offset, depth), omni_lights.data[idx].shadow_opacity);
 		}
 
 		return shadow;
@@ -674,7 +675,7 @@ void light_process_omni(uint idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 v
 
 float light_process_spot_shadow(uint idx, vec3 vertex, vec3 normal) {
 #ifndef SHADOWS_DISABLED
-	if (spot_lights.data[idx].shadow_enabled) {
+	if (spot_lights.data[idx].shadow_opacity > 0.001) {
 		vec3 light_rel_vec = spot_lights.data[idx].position - vertex;
 		float light_length = length(light_rel_vec);
 		vec3 spot_dir = spot_lights.data[idx].direction;
@@ -735,6 +736,7 @@ float light_process_spot_shadow(uint idx, vec3 vertex, vec3 normal) {
 				}
 
 				shadow /= float(sc_penumbra_shadow_samples);
+				shadow = mix(1.0, shadow, spot_lights.data[idx].shadow_opacity);
 
 			} else {
 				//no blockers found, so no shadow
@@ -743,7 +745,7 @@ float light_process_spot_shadow(uint idx, vec3 vertex, vec3 normal) {
 		} else {
 			//hard shadow
 			vec3 shadow_uv = vec3(splane.xy * spot_lights.data[idx].atlas_rect.zw + spot_lights.data[idx].atlas_rect.xy, splane.z);
-			shadow = sample_pcf_shadow(shadow_atlas, spot_lights.data[idx].soft_shadow_scale * scene_data_block.data.shadow_atlas_pixel_size, shadow_uv);
+			shadow = mix(1.0, sample_pcf_shadow(shadow_atlas, spot_lights.data[idx].soft_shadow_scale * scene_data_block.data.shadow_atlas_pixel_size, shadow_uv), spot_lights.data[idx].shadow_opacity);
 		}
 
 		return shadow;
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
index 26d0de46c2..eb73a33558 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
@@ -1134,7 +1134,7 @@ void main() {
 
 #ifdef USE_SOFT_SHADOWS
 			//version with soft shadows, more expensive
-			if (directional_lights.data[i].shadow_enabled) {
+			if (directional_lights.data[i].shadow_opacity > 0.001) {
 				float depth_z = -vertex.z;
 
 				vec4 pssm_coord;
@@ -1286,7 +1286,7 @@ void main() {
 #else
 			// Soft shadow disabled version
 
-			if (directional_lights.data[i].shadow_enabled) {
+			if (directional_lights.data[i].shadow_opacity > 0.001) {
 				float depth_z = -vertex.z;
 
 				vec4 pssm_coord;