Eevee: SSS: Add Quality settings.

Samples : pretty self explanatory.
Jitter Threshold : Reduce cache misses and improve performance (greatly) by lowering this value. This settings let user decide how many samples should be jittered (rotated) to reduce banding artifacts.

5 files changed, 25 insertions, 26 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_engine.c b/source/blender/draw/engines/eevee/eevee_engine.c
index 217dc2f0227..4ca59aaa39e 100644
--- a/source/blender/draw/engines/eevee/eevee_engine.c
+++ b/source/blender/draw/engines/eevee/eevee_engine.c
@@ -323,6 +323,8 @@ static void EEVEE_scene_layer_settings_create(RenderEngine *UNUSED(engine), IDPr
 	BKE_collection_engine_property_add_int(props, "taa_samples", 8);
 
 	BKE_collection_engine_property_add_bool(props, "sss_enable", false);
+	BKE_collection_engine_property_add_int(props, "sss_samples", 7);
+	BKE_collection_engine_property_add_float(props, "sss_jitter_threshold", 0.3f);
 
 	BKE_collection_engine_property_add_bool(props, "ssr_enable", false);
 	BKE_collection_engine_property_add_bool(props, "ssr_refraction", false);
diff --git a/source/blender/draw/engines/eevee/eevee_materials.c b/source/blender/draw/engines/eevee/eevee_materials.c
index f7985fb7ddf..23057bd91c0 100644
--- a/source/blender/draw/engines/eevee/eevee_materials.c
+++ b/source/blender/draw/engines/eevee/eevee_materials.c
@@ -1006,7 +1006,8 @@ static void material_opaque(
 			add_standard_uniforms(*shgrp, sldata, vedata, ssr_id, &ma->refract_depth, use_refract, false);
 
 			if (use_sss) {
-				struct GPUUniformBuffer *sss_profile = GPU_material_sss_profile_get(*gpumat);
+				struct GPUUniformBuffer *sss_profile = GPU_material_sss_profile_get(*gpumat,
+				                                                                    stl->effects->sss_sample_count);
 				if (sss_profile) {
 					DRW_shgroup_stencil_mask(*shgrp, e_data.sss_count + 1);
 					EEVEE_subsurface_add_pass(vedata, e_data.sss_count + 1, sss_profile);
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 43540762a52..b1ed108bad0 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -429,6 +429,10 @@ typedef struct EEVEE_EffectsInfo {
 	int enabled_effects;
 	bool swap_double_buffer;
 
+	/* SSSS */
+	int sss_sample_count;
+	float sss_jitter_threshold;
+
 	/* Volumetrics */
 	bool use_volumetrics;
 	int volume_current_sample;
diff --git a/source/blender/draw/engines/eevee/eevee_subsurface.c b/source/blender/draw/engines/eevee/eevee_subsurface.c
index b2f3d1fee48..2784125ca58 100644
--- a/source/blender/draw/engines/eevee/eevee_subsurface.c
+++ b/source/blender/draw/engines/eevee/eevee_subsurface.c
@@ -19,7 +19,7 @@
  *
  */
 
-/* Screen space reflections and refractions techniques.
+/* Screen space subsurface scattering technique.
  */
 
 /** \file eevee_subsurface.c
@@ -33,16 +33,7 @@
 #include "eevee_private.h"
 #include "GPU_texture.h"
 
-/* SSR shader variations */
-enum {
-	SSR_SAMPLES      = (1 << 0) | (1 << 1),
-	SSR_RESOLVE      = (1 << 2),
-	SSR_FULL_TRACE   = (1 << 3),
-	SSR_MAX_SHADER   = (1 << 4),
-};
-
 static struct {
-	/* Screen Space SubSurfaceScattering */
 	struct GPUShader *sss_sh[2];
 } e_data = {NULL}; /* Engine data */
 
@@ -56,6 +47,8 @@ static void eevee_create_shader_subsurface(void)
 
 int EEVEE_subsurface_init(EEVEE_SceneLayerData *UNUSED(sldata), EEVEE_Data *vedata)
 {
+	EEVEE_StorageList *stl = vedata->stl;
+	EEVEE_EffectsInfo *effects = stl->effects;
 	EEVEE_FramebufferList *fbl = vedata->fbl;
 	EEVEE_TextureList *txl = vedata->txl;
 	const float *viewport_size = DRW_viewport_size_get();
@@ -65,6 +58,8 @@ int EEVEE_subsurface_init(EEVEE_SceneLayerData *UNUSED(sldata), EEVEE_Data *veda
 	IDProperty *props = BKE_scene_layer_engine_evaluated_get(scene_layer, COLLECTION_MODE_NONE, RE_engine_id_BLENDER_EEVEE);
 
 	if (BKE_collection_engine_property_value_get_bool(props, "sss_enable")) {
+		effects->sss_sample_count = 1 + BKE_collection_engine_property_value_get_int(props, "sss_samples") * 2;
+		effects->sss_jitter_threshold = BKE_collection_engine_property_value_get_float(props, "sss_jitter_threshold");
 
 		/* Shaders */
 		if (!e_data.sss_sh[0]) {
@@ -119,6 +114,8 @@ void EEVEE_subsurface_add_pass(EEVEE_Data *vedata, unsigned int sss_id, struct G
 	DefaultTextureList *dtxl = DRW_viewport_texture_list_get();
 	EEVEE_TextureList *txl = vedata->txl;
 	EEVEE_PassList *psl = vedata->psl;
+	EEVEE_StorageList *stl = vedata->stl;
+	EEVEE_EffectsInfo *effects = stl->effects;
 	struct Gwn_Batch *quad = DRW_cache_fullscreen_quad_get();
 
 	DRWShadingGroup *grp = DRW_shgroup_create(e_data.sss_sh[0], psl->sss_blur_ps);
@@ -127,6 +124,8 @@ void EEVEE_subsurface_add_pass(EEVEE_Data *vedata, unsigned int sss_id, struct G
 	DRW_shgroup_uniform_buffer(grp, "depthBuffer", &dtxl->depth);
 	DRW_shgroup_uniform_buffer(grp, "sssData", &txl->sss_data);
 	DRW_shgroup_uniform_block(grp, "sssProfile", sss_profile);
+	DRW_shgroup_uniform_int(grp, "sampleCount", &effects->sss_sample_count, 1);
+	DRW_shgroup_uniform_float(grp, "jitterThreshold", &effects->sss_jitter_threshold, 1);
 	DRW_shgroup_stencil_mask(grp, sss_id);
 	DRW_shgroup_call_add(grp, quad, NULL);
 
@@ -136,6 +135,8 @@ void EEVEE_subsurface_add_pass(EEVEE_Data *vedata, unsigned int sss_id, struct G
 	DRW_shgroup_uniform_buffer(grp, "depthBuffer", &dtxl->depth);
 	DRW_shgroup_uniform_buffer(grp, "sssData", &txl->sss_blur);
 	DRW_shgroup_uniform_block(grp, "sssProfile", sss_profile);
+	DRW_shgroup_uniform_int(grp, "sampleCount", &effects->sss_sample_count, 1);
+	DRW_shgroup_uniform_float(grp, "jitterThreshold", &effects->sss_jitter_threshold, 1);
 	DRW_shgroup_stencil_mask(grp, sss_id);
 	DRW_shgroup_call_add(grp, quad, NULL);
 }
diff --git a/source/blender/draw/engines/eevee/shaders/effect_subsurface_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_subsurface_frag.glsl
index 5cc47796ec0..9ee713ab483 100644
--- a/source/blender/draw/engines/eevee/shaders/effect_subsurface_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/effect_subsurface_frag.glsl
@@ -1,12 +1,14 @@
 
 /* Based on Separable SSS. by Jorge Jimenez and Diego Gutierrez */
 
-#define SSS_SAMPLES 25
+#define MAX_SSS_SAMPLES 65
 layout(std140) uniform sssProfile {
-	vec4 kernel[SSS_SAMPLES];
+	vec4 kernel[MAX_SSS_SAMPLES];
 	vec4 radii_max_radius;
 };
 
+uniform int sampleCount;
+uniform float jitterThreshold;
 uniform sampler2D depthBuffer;
 uniform sampler2D sssData;
 uniform sampler2DArray utilTex;
@@ -27,16 +29,6 @@ float get_view_z_from_depth(float depth)
 	}
 }
 
-vec3 get_view_space_from_depth(vec2 uvcoords, float depth)
-{
-	if (ProjectionMatrix[3][3] == 0.0) {
-		return (viewvecs[0].xyz + vec3(uvcoords, 0.0) * viewvecs[1].xyz) * get_view_z_from_depth(depth);
-	}
-	else {
-		return viewvecs[0].xyz + vec3(uvcoords, depth) * viewvecs[1].xyz;
-	}
-}
-
 #define LUT_SIZE 64
 #define M_PI_2     1.5707963267948966        /* pi/2 */
 #define M_2PI      6.2831853071795865        /* 2*pi */
@@ -67,9 +59,8 @@ void main(void)
 	/* Center sample */
 	vec3 accum = sss_data.rgb * kernel[0].rgb;
 
-	for (int i = 1; i < SSS_SAMPLES; i++) {
-		/* Rotate samples that are near the kernel center. */
-		vec2 sample_uv = uvs + kernel[i].a * finalStep * ((abs(kernel[i].a) > 0.3) ? dir : dir_rand);
+	for (int i = 1; i < sampleCount && i < MAX_SSS_SAMPLES; i++) {
+		vec2 sample_uv = uvs + kernel[i].a * finalStep * ((abs(kernel[i].a) > jitterThreshold) ? dir : dir_rand);
 		vec3 color = texture(sssData, sample_uv).rgb;
 		float sample_depth = texture(depthBuffer, sample_uv).r;
 		sample_depth = get_view_z_from_depth(sample_depth);