Add Soft Very Low shadow quality mode for 3D

This can be used to improve 3D shadow rendering quality at little
performance cost. Unlike the existing Hard setting which is limited
to variable shadow blur only, it works with both fixed blur and
variable blur.

2 files changed, 15 insertions, 5 deletions

diff --git a/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp b/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
index d128578d0b..a906a853dc 100644
--- a/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
@@ -2696,9 +2696,14 @@ void RendererSceneRenderRD::shadows_quality_set(RS::ShadowQuality p_quality) {
 		switch (shadows_quality) {
 			case RS::SHADOW_QUALITY_HARD: {
 				penumbra_shadow_samples = 4;
-				soft_shadow_samples = 1;
+				soft_shadow_samples = 0;
 				shadows_quality_radius = 1.0;
 			} break;
+			case RS::SHADOW_QUALITY_SOFT_VERY_LOW: {
+				penumbra_shadow_samples = 4;
+				soft_shadow_samples = 1;
+				shadows_quality_radius = 1.5;
+			} break;
 			case RS::SHADOW_QUALITY_SOFT_LOW: {
 				penumbra_shadow_samples = 8;
 				soft_shadow_samples = 4;
@@ -2738,9 +2743,14 @@ void RendererSceneRenderRD::directional_shadow_quality_set(RS::ShadowQuality p_q
 		switch (directional_shadow_quality) {
 			case RS::SHADOW_QUALITY_HARD: {
 				directional_penumbra_shadow_samples = 4;
-				directional_soft_shadow_samples = 1;
+				directional_soft_shadow_samples = 0;
 				directional_shadow_quality_radius = 1.0;
 			} break;
+			case RS::SHADOW_QUALITY_SOFT_VERY_LOW: {
+				directional_penumbra_shadow_samples = 4;
+				directional_soft_shadow_samples = 1;
+				directional_shadow_quality_radius = 1.5;
+			} break;
 			case RS::SHADOW_QUALITY_SOFT_LOW: {
 				directional_penumbra_shadow_samples = 8;
 				directional_soft_shadow_samples = 4;
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 4d466342f8..72872c9c08 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl
@@ -301,7 +301,7 @@ float sample_directional_pcf_shadow(texture2D shadow, vec2 shadow_pixel_size, ve
 	float depth = coord.z;
 
 	//if only one sample is taken, take it from the center
-	if (sc_directional_soft_shadow_samples == 1) {
+	if (sc_directional_soft_shadow_samples == 0) {
 		return textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
 	}
 
@@ -327,7 +327,7 @@ float sample_pcf_shadow(texture2D shadow, vec2 shadow_pixel_size, vec3 coord) {
 	float depth = coord.z;
 
 	//if only one sample is taken, take it from the center
-	if (sc_soft_shadow_samples == 1) {
+	if (sc_soft_shadow_samples == 0) {
 		return textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));
 	}
 
@@ -350,7 +350,7 @@ float sample_pcf_shadow(texture2D shadow, vec2 shadow_pixel_size, vec3 coord) {
 
 float sample_omni_pcf_shadow(texture2D shadow, float blur_scale, vec2 coord, vec4 uv_rect, vec2 flip_offset, float depth) {
 	//if only one sample is taken, take it from the center
-	if (sc_soft_shadow_samples == 1) {
+	if (sc_soft_shadow_samples == 0) {
 		vec2 pos = coord * 0.5 + 0.5;
 		pos = uv_rect.xy + pos * uv_rect.zw;
 		return textureProj(sampler2DShadow(shadow, shadow_sampler), vec4(pos, depth, 1.0));