Ported from godot: add support for 3 dir shadow splits

- Ansraer
54bc6a300e

doc/classes/DirectionalLight.xml

@@ -24,7 +24,7 @@
 		<member name="directional_shadow_max_distance" type="float" setter="set_param" getter="get_param" default="100.0">
 			The maximum distance for shadow splits. Increasing this value will make directional shadows visible from further away, at the cost of lower overall shadow detail and performance (since more objects need to be included in the directional shadow rendering).
 		</member>
-		<member name="directional_shadow_mode" type="int" setter="set_shadow_mode" getter="get_shadow_mode" enum="DirectionalLight.ShadowMode" default="2">
+		<member name="directional_shadow_mode" type="int" setter="set_shadow_mode" getter="get_shadow_mode" enum="DirectionalLight.ShadowMode" default="3">
 			The light's shadow rendering algorithm. See [enum ShadowMode].
 		</member>
 		<member name="directional_shadow_normal_bias" type="float" setter="set_param" getter="get_param" default="0.8">
@@ -47,7 +47,10 @@
 		<constant name="SHADOW_PARALLEL_2_SPLITS" value="1" enum="ShadowMode">
 			Splits the view frustum in 2 areas, each with its own shadow map. This shadow mode is a compromise between [constant SHADOW_ORTHOGONAL] and [constant SHADOW_PARALLEL_4_SPLITS] in terms of performance.
 		</constant>
-		<constant name="SHADOW_PARALLEL_4_SPLITS" value="2" enum="ShadowMode">
+		<constant name="SHADOW_PARALLEL_3_SPLITS" value="2" enum="ShadowMode">
+			Splits the view frustum in 3 areas, each with its own shadow map. This shadow mode is a compromise between [constant SHADOW_ORTHOGONAL] and [constant SHADOW_PARALLEL_4_SPLITS] in terms of performance.
+		</constant>
+		<constant name="SHADOW_PARALLEL_4_SPLITS" value="3" enum="ShadowMode">
 			Splits the view frustum in 4 areas, each with its own shadow map. This is the slowest directional shadow mode.
 		</constant>
 		<constant name="SHADOW_DEPTH_RANGE_STABLE" value="0" enum="ShadowDepthRange">

doc/classes/RenderingServer.xml

@@ -3153,7 +3153,10 @@
 		<constant name="LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS" value="1" enum="LightDirectionalShadowMode">
 			Use 2 splits for shadow projection when using directional light.
 		</constant>
-		<constant name="LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS" value="2" enum="LightDirectionalShadowMode">
+		<constant name="LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS" value="2" enum="LightDirectionalShadowMode">
+			Use 3 splits for shadow projection when using directional light.
+		</constant>
+		<constant name="LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS" value="3" enum="LightDirectionalShadowMode">
 			Use 4 splits for shadow projection when using directional light.
 		</constant>
 		<constant name="LIGHT_DIRECTIONAL_SHADOW_DEPTH_RANGE_STABLE" value="0" enum="LightDirectionalShadowDepthRangeMode">

drivers/gles2/rasterizer_scene_gles2.cpp

@@ -513,6 +513,7 @@ int RasterizerSceneGLES2::get_directional_light_shadow_size(RID p_light_intance)
 		case RS::LIGHT_DIRECTIONAL_SHADOW_ORTHOGONAL:
 			break; //none
 		case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS:
+		case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS:
 		case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS:
 			shadow_size /= 2;
 			break;
@@ -1906,7 +1907,9 @@ void RasterizerSceneGLES2::_setup_light_type(LightInstance *p_light, ShadowAtlas
 				} break;
 				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS: {
 					state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM2, true);
-
+				} break;
+				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS: {
+					state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM3, true);
 				} break;
 				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS: {
 					state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM4, true);
@@ -1995,6 +1998,10 @@ void RasterizerSceneGLES2::_setup_light(LightInstance *light, ShadowAtlas *shado
 						shadow_count = 2;
 					} break;
 
+					case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS: {
+						shadow_count = 3;
+					} break;
+
 					case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS: {
 						shadow_count = 4;
 					} break;
@@ -2006,7 +2013,8 @@ void RasterizerSceneGLES2::_setup_light(LightInstance *light, ShadowAtlas *shado
 					uint32_t width = light->directional_rect.size.x;
 					uint32_t height = light->directional_rect.size.y;
 
-					if (light_ptr->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
+					if (light_ptr->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS || 
+							light_ptr->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
 						width /= 2;
 						height /= 2;
 
@@ -2593,6 +2601,7 @@ void RasterizerSceneGLES2::_render_render_list(RenderList::Element **p_elements,
 	state.scene_shader.set_conditional(SceneShaderGLES2::USE_INSTANCING, false);
 	state.scene_shader.set_conditional(SceneShaderGLES2::USE_RADIANCE_MAP, false);
 	state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM4, false);
+	state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM3, false);
 	state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM2, false);
 	state.scene_shader.set_conditional(SceneShaderGLES2::LIGHT_USE_PSSM_BLEND, false);
 	state.scene_shader.set_conditional(SceneShaderGLES2::USE_VERTEX_LIGHTING, false);
@@ -3576,7 +3585,8 @@ void RasterizerSceneGLES2::render_shadow(RID p_light, RID p_shadow_atlas, int p_
 		width = light_instance->directional_rect.size.width;
 		height = light_instance->directional_rect.size.height;
 
-		if (light->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
+		if (light->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS 
+				|| light->directional_shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
 			width /= 2;
 			height /= 2;
 

drivers/gles2/shaders/scene.glsl

@@ -166,18 +166,19 @@ uniform highp float shadow_dual_paraboloid_render_side;
 uniform highp mat4 light_shadow_matrix;
 varying highp vec4 shadow_coord;
 
-#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
 uniform highp mat4 light_shadow_matrix2;
 varying highp vec4 shadow_coord2;
 #endif
 
-#if defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
-
 uniform highp mat4 light_shadow_matrix3;
-uniform highp mat4 light_shadow_matrix4;
 varying highp vec4 shadow_coord3;
-varying highp vec4 shadow_coord4;
+#endif
 
+#if defined(LIGHT_USE_PSSM4)
+uniform highp mat4 light_shadow_matrix4;
+varying highp vec4 shadow_coord4;
 #endif
 
 #endif
@@ -648,14 +649,16 @@ VERTEX_SHADER_CODE
 	vec4 vi4 = vec4(vertex_interp, 1.0);
 	shadow_coord = light_shadow_matrix * vi4;
 
-#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
 	shadow_coord2 = light_shadow_matrix2 * vi4;
 #endif
 
-#if defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
 	shadow_coord3 = light_shadow_matrix3 * vi4;
-	shadow_coord4 = light_shadow_matrix4 * vi4;
+#endif
 
+#if defined(LIGHT_USE_PSSM4)
+	shadow_coord4 = light_shadow_matrix4 * vi4;
 #endif
 
 #endif //use shadow and use lighting
@@ -1017,15 +1020,16 @@ uniform highp vec4 light_split_offsets;
 
 varying highp vec4 shadow_coord;
 
-#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM2) || defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
 varying highp vec4 shadow_coord2;
 #endif
 
-#if defined(LIGHT_USE_PSSM4)
+#if defined(LIGHT_USE_PSSM3) || defined(LIGHT_USE_PSSM4)
-
 varying highp vec4 shadow_coord3;
-varying highp vec4 shadow_coord4;
+#endif
 
+#if defined(LIGHT_USE_PSSM4)
+varying highp vec4 shadow_coord4;
 #endif
 
 uniform vec4 light_clamp;
@@ -1892,6 +1896,55 @@ FRAGMENT_SHADER_CODE
 
 #endif //LIGHT_USE_PSSM4
 
+#ifdef LIGHT_USE_PSSM3
+	//take advantage of prefetch
+	float shadow1 = sample_shadow(light_directional_shadow, shadow_coord);
+	float shadow2 = sample_shadow(light_directional_shadow, shadow_coord2);
+	float shadow3 = sample_shadow(light_directional_shadow, shadow_coord3);
+
+	if (depth_z < light_split_offsets.z) {
+		float pssm_fade = 0.0;
+		float shadow_att = 1.0;
+#ifdef LIGHT_USE_PSSM_BLEND
+		float shadow_att2 = 1.0;
+		float pssm_blend = 0.0;
+		bool use_blend = true;
+#endif
+		if (depth_z < light_split_offsets.y) {
+			if (depth_z < light_split_offsets.x) {
+				shadow_att = shadow1;
+
+#ifdef LIGHT_USE_PSSM_BLEND
+				shadow_att2 = shadow2;
+
+				pssm_blend = smoothstep(0.0, light_split_offsets.x, depth_z);
+#endif
+			} else {
+				shadow_att = shadow2;
+
+#ifdef LIGHT_USE_PSSM_BLEND
+				shadow_att2 = shadow3;
+
+				pssm_blend = smoothstep(light_split_offsets.x, light_split_offsets.y, depth_z);
+#endif
+			}
+		} else {
+			shadow_att = shadow3;
+
+#if defined(LIGHT_USE_PSSM_BLEND)
+			use_blend = false;
+#endif
+		}
+#if defined(LIGHT_USE_PSSM_BLEND)
+		if (use_blend) {
+			shadow_att = mix(shadow_att, shadow_att2, pssm_blend);
+		}
+#endif
+		light_att *= mix(shadow_color.rgb, vec3(1.0), shadow_att);
+	}
+
+#endif //LIGHT_USE_PSSM3
+
 #ifdef LIGHT_USE_PSSM2
 
 	//take advantage of prefetch
@@ -1932,7 +1985,7 @@ FRAGMENT_SHADER_CODE
 
 #endif //LIGHT_USE_PSSM2
 
-#if !defined(LIGHT_USE_PSSM4) && !defined(LIGHT_USE_PSSM2)
+#if !defined(LIGHT_USE_PSSM4) && !defined(LIGHT_USE_PSSM3) && !defined(LIGHT_USE_PSSM2)
 
 	light_att *= mix(shadow_color.rgb, vec3(1.0), sample_shadow(light_directional_shadow, shadow_coord));
 #endif //orthogonal
@@ -1942,6 +1995,8 @@ FRAGMENT_SHADER_CODE
 	{
 #ifdef LIGHT_USE_PSSM4
 		if (depth_z < light_split_offsets.w) {
+#elif defined(LIGHT_USE_PSSM3)
+		if (depth_z < light_split_offsets.z) {
 #elif defined(LIGHT_USE_PSSM2)
 		if (depth_z < light_split_offsets.y) {
 #else
@@ -1998,6 +2053,35 @@ FRAGMENT_SHADER_CODE
 
 #endif // LIGHT_USE_PSSM4
 
+#ifdef LIGHT_USE_PSSM3
+
+			if (depth_z < light_split_offsets.y) {
+				if (depth_z < light_split_offsets.x) {
+					pssm_coord = shadow_coord;
+
+#ifdef LIGHT_USE_PSSM_BLEND
+					pssm_coord2 = shadow_coord2;
+					pssm_blend = smoothstep(0.0, light_split_offsets.x, depth_z);
+#endif
+				} else {
+					pssm_coord = shadow_coord2;
+
+#ifdef LIGHT_USE_PSSM_BLEND
+					pssm_coord2 = shadow_coord3;
+					pssm_blend = smoothstep(light_split_offsets.x, light_split_offsets.y, depth_z);
+#endif
+				}
+			} else {
+				pssm_coord = shadow_coord3;
+				pssm_fade = smoothstep(light_split_offsets.y, light_split_offsets.z, depth_z);
+
+#if defined(LIGHT_USE_PSSM_BLEND)
+				use_blend = false;
+#endif
+			}
+
+#endif // LIGHT_USE_PSSM3
+
 #ifdef LIGHT_USE_PSSM2
 			if (depth_z < light_split_offsets.x) {
 				pssm_coord = shadow_coord;
@@ -2016,7 +2100,7 @@ FRAGMENT_SHADER_CODE
 
 #endif // LIGHT_USE_PSSM2
 
-#if !defined(LIGHT_USE_PSSM4) && !defined(LIGHT_USE_PSSM2)
+#if !defined(LIGHT_USE_PSSM4) && !defined(LIGHT_USE_PSSM3) && !defined(LIGHT_USE_PSSM2)
 			{
 				pssm_coord = shadow_coord;
 			}

scene/3d/light.cpp

@@ -363,7 +363,7 @@ void DirectionalLight::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("is_blend_splits_enabled"), &DirectionalLight::is_blend_splits_enabled);
 
 	ADD_GROUP("Directional Shadow", "directional_shadow_");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "directional_shadow_mode", PROPERTY_HINT_ENUM, "Orthogonal (Fast),PSSM 2 Splits (Average),PSSM 4 Splits (Slow)"), "set_shadow_mode", "get_shadow_mode");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "directional_shadow_mode", PROPERTY_HINT_ENUM, "Orthogonal (Fast),PSSM 2 Splits (Average),PSSM 3 Splits (Slow),PSSM 4 Splits (Very Slow)"), "set_shadow_mode", "get_shadow_mode");
 	ADD_PROPERTYI(PropertyInfo(Variant::REAL, "directional_shadow_split_1", PROPERTY_HINT_RANGE, "0,1,0.001"), "set_param", "get_param", PARAM_SHADOW_SPLIT_1_OFFSET);
 	ADD_PROPERTYI(PropertyInfo(Variant::REAL, "directional_shadow_split_2", PROPERTY_HINT_RANGE, "0,1,0.001"), "set_param", "get_param", PARAM_SHADOW_SPLIT_2_OFFSET);
 	ADD_PROPERTYI(PropertyInfo(Variant::REAL, "directional_shadow_split_3", PROPERTY_HINT_RANGE, "0,1,0.001"), "set_param", "get_param", PARAM_SHADOW_SPLIT_3_OFFSET);
@@ -375,6 +375,7 @@ void DirectionalLight::_bind_methods() {
 
 	BIND_ENUM_CONSTANT(SHADOW_ORTHOGONAL);
 	BIND_ENUM_CONSTANT(SHADOW_PARALLEL_2_SPLITS);
+	BIND_ENUM_CONSTANT(SHADOW_PARALLEL_3_SPLITS);
 	BIND_ENUM_CONSTANT(SHADOW_PARALLEL_4_SPLITS);
 
 	BIND_ENUM_CONSTANT(SHADOW_DEPTH_RANGE_STABLE);

scene/3d/light.h

@@ -126,6 +126,7 @@ public:
 	enum ShadowMode {
 		SHADOW_ORTHOGONAL,
 		SHADOW_PARALLEL_2_SPLITS,
+		SHADOW_PARALLEL_3_SPLITS,
 		SHADOW_PARALLEL_4_SPLITS
 	};
 

servers/rendering/rendering_server_scene.cpp

@@ -2117,6 +2117,9 @@ bool RenderingServerScene::_light_instance_update_shadow(Instance *p_instance, c
 				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS:
 					splits = 2;
 					break;
+				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS:
+					splits = 3;
+					break;
 				case RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS:
 					splits = 4;
 					break;

servers/rendering_server.cpp

@@ -2325,6 +2325,7 @@ void RenderingServer::_bind_methods() {
 
 	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_ORTHOGONAL);
 	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS);
+	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS);
 	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS);
 	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_DEPTH_RANGE_STABLE);
 	BIND_ENUM_CONSTANT(LIGHT_DIRECTIONAL_SHADOW_DEPTH_RANGE_OPTIMIZED);

servers/rendering_server.h

@@ -483,6 +483,7 @@ public:
 	enum LightDirectionalShadowMode {
 		LIGHT_DIRECTIONAL_SHADOW_ORTHOGONAL,
 		LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS,
+		LIGHT_DIRECTIONAL_SHADOW_PARALLEL_3_SPLITS,
 		LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS
 	};