Eevee: Add Planar reflection blurring.

This method is very cheap and inaccurate. This will fill the gap untill better model is supported.

8 files changed, 135 insertions, 5 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_engine.c b/source/blender/draw/engines/eevee/eevee_engine.c
index c024eb609b3..88f16e41d6b 100644
--- a/source/blender/draw/engines/eevee/eevee_engine.c
+++ b/source/blender/draw/engines/eevee/eevee_engine.c
@@ -71,12 +71,11 @@ static void EEVEE_engine_init(void *ved)
 static void EEVEE_cache_init(void *vedata)
 {
 	EEVEE_PassList *psl = ((EEVEE_Data *)vedata)->psl;
-	EEVEE_StorageList *stl = ((EEVEE_Data *)vedata)->stl;
 	EEVEE_SceneLayerData *sldata = EEVEE_scene_layer_data_get();
 
 	EEVEE_materials_cache_init(vedata);
 	EEVEE_lights_cache_init(sldata, psl);
-	EEVEE_lightprobes_cache_init(sldata, psl, stl);
+	EEVEE_lightprobes_cache_init(sldata, vedata);
 	EEVEE_effects_cache_init(vedata);
 }
 
diff --git a/source/blender/draw/engines/eevee/eevee_lightprobes.c b/source/blender/draw/engines/eevee/eevee_lightprobes.c
index 8ec603030c5..b85116adc81 100644
--- a/source/blender/draw/engines/eevee/eevee_lightprobes.c
+++ b/source/blender/draw/engines/eevee/eevee_lightprobes.c
@@ -57,6 +57,7 @@ static struct {
 	struct GPUShader *probe_filter_diffuse_sh;
 	struct GPUShader *probe_grid_display_sh;
 	struct GPUShader *probe_planar_display_sh;
+	struct GPUShader *probe_planar_downsample_sh;
 	struct GPUShader *probe_cube_display_sh;
 
 	struct GPUTexture *hammersley;
@@ -78,6 +79,9 @@ extern char datatoc_lightprobe_geom_glsl[];
 extern char datatoc_lightprobe_vert_glsl[];
 extern char datatoc_lightprobe_planar_display_frag_glsl[];
 extern char datatoc_lightprobe_planar_display_vert_glsl[];
+extern char datatoc_lightprobe_planar_downsample_frag_glsl[];
+extern char datatoc_lightprobe_planar_downsample_geom_glsl[];
+extern char datatoc_lightprobe_planar_downsample_vert_glsl[];
 extern char datatoc_lightprobe_cube_display_frag_glsl[];
 extern char datatoc_lightprobe_cube_display_vert_glsl[];
 extern char datatoc_lightprobe_grid_display_frag_glsl[];
@@ -254,6 +258,12 @@ void EEVEE_lightprobes_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *UNUSED(ved
 
 		MEM_freeN(shader_str);
 
+		e_data.probe_planar_downsample_sh = DRW_shader_create(
+		        datatoc_lightprobe_planar_downsample_vert_glsl,
+		        datatoc_lightprobe_planar_downsample_geom_glsl,
+		        datatoc_lightprobe_planar_downsample_frag_glsl,
+		        NULL);
+
 		e_data.hammersley = create_hammersley_sample_texture(1024);
 	}
 
@@ -296,8 +306,11 @@ void EEVEE_lightprobes_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *UNUSED(ved
 	}
 }
 
-void EEVEE_lightprobes_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_PassList *psl, EEVEE_StorageList *stl)
+void EEVEE_lightprobes_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 {
+	EEVEE_TextureList *txl = vedata->txl;
+	EEVEE_PassList *psl = vedata->psl;
+	EEVEE_StorageList *stl = vedata->stl;
 	EEVEE_LightProbesInfo *pinfo = sldata->probes;
 
 	pinfo->num_cube = 1; /* at least one for the world */
@@ -406,6 +419,15 @@ void EEVEE_lightprobes_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_PassList *
 		DRW_shgroup_uniform_float(grp, "lodMax", &sldata->probes->lodmax, 1);
 		DRW_shgroup_uniform_buffer(grp, "probeCubes", &sldata->probe_pool);
 	}
+
+	{
+		psl->probe_planar_downsample_ps = DRW_pass_create("LightProbe Planar Downsample", DRW_STATE_WRITE_COLOR);
+
+		struct Gwn_Batch *geom = DRW_cache_fullscreen_quad_get();
+		DRWShadingGroup *grp = stl->g_data->planar_downsample = DRW_shgroup_instance_create(e_data.probe_planar_downsample_sh, psl->probe_planar_downsample_ps, geom);
+		DRW_shgroup_uniform_buffer(grp, "source", &txl->planar_pool);
+		DRW_shgroup_uniform_vec2(grp, "texelSize", stl->g_data->texel_size, 1);
+	}
 }
 
 void EEVEE_lightprobes_cache_add(EEVEE_SceneLayerData *sldata, Object *ob)
@@ -688,6 +710,7 @@ static void EEVEE_lightprobes_updates(EEVEE_SceneLayerData *sldata, EEVEE_PassLi
 
 void EEVEE_lightprobes_cache_finish(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 {
+	EEVEE_StorageList *stl = vedata->stl;
 	EEVEE_LightProbesInfo *pinfo = sldata->probes;
 	Object *ob;
 
@@ -705,6 +728,9 @@ void EEVEE_lightprobes_cache_finish(EEVEE_SceneLayerData *sldata, EEVEE_Data *ve
 	/* XXX this should be run each frame as it ensure planar_depth is set */
 	planar_pool_ensure_alloc(vedata, pinfo->num_planar);
 
+	/* Setup planar filtering pass */
+	DRW_shgroup_set_instance_count(stl->g_data->planar_downsample, pinfo->num_planar);
+
 	if (!sldata->probe_pool) {
 		sldata->probe_pool = DRW_texture_create_2D_array(PROBE_OCTAHEDRON_SIZE, PROBE_OCTAHEDRON_SIZE, max_ff(1, pinfo->num_cube),
 		                                                 DRW_TEX_RGB_11_11_10, DRW_TEX_FILTER | DRW_TEX_MIPMAP, NULL);
@@ -772,6 +798,24 @@ void EEVEE_lightprobes_cache_finish(EEVEE_SceneLayerData *sldata, EEVEE_Data *ve
 	DRW_uniformbuffer_update(sldata->planar_ubo, &sldata->probes->planar_data);
 }
 
+static void downsample_planar(void *vedata, int level)
+{
+	EEVEE_PassList *psl = ((EEVEE_Data *)vedata)->psl;
+	EEVEE_StorageList *stl = ((EEVEE_Data *)vedata)->stl;
+
+	const float *size = DRW_viewport_size_get();
+	copy_v2_v2(stl->g_data->texel_size, size);
+	for (int i = 0; i < level - 1; ++i) {
+		stl->g_data->texel_size[0] /= 2.0f;
+		stl->g_data->texel_size[1] /= 2.0f;
+		min_ff(floorf(stl->g_data->texel_size[0]), 1.0f);
+		min_ff(floorf(stl->g_data->texel_size[1]), 1.0f);
+	}
+	invert_v2(stl->g_data->texel_size);
+
+	DRW_draw_pass(psl->probe_planar_downsample_ps);
+}
+
 /* Glossy filter probe_rt to probe_pool at index probe_idx */
 static void glossy_filter_probe(EEVEE_SceneLayerData *sldata, EEVEE_PassList *psl, int probe_idx)
 {
@@ -1099,6 +1143,7 @@ static void lightprobe_cell_location_get(EEVEE_LightGrid *egrid, int cell_idx, f
 
 void EEVEE_lightprobes_refresh(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 {
+	EEVEE_TextureList *txl = vedata->txl;
 	EEVEE_PassList *psl = vedata->psl;
 	EEVEE_LightProbesInfo *pinfo = sldata->probes;
 	Object *ob;
@@ -1246,6 +1291,11 @@ update_planar:
 			ped->probe_id = i;
 		}
 	}
+
+	/* If there is at least one planar probe */
+	if (pinfo->num_planar > 0) {
+		DRW_framebuffer_recursive_downsample(vedata->fbl->minmaxz_fb, txl->planar_pool, 5, &downsample_planar, vedata);
+	}
 }
 
 void EEVEE_lightprobes_free(void)
@@ -1255,6 +1305,7 @@ void EEVEE_lightprobes_free(void)
 	DRW_SHADER_FREE_SAFE(e_data.probe_filter_diffuse_sh);
 	DRW_SHADER_FREE_SAFE(e_data.probe_grid_display_sh);
 	DRW_SHADER_FREE_SAFE(e_data.probe_planar_display_sh);
+	DRW_SHADER_FREE_SAFE(e_data.probe_planar_downsample_sh);
 	DRW_SHADER_FREE_SAFE(e_data.probe_cube_display_sh);
 	DRW_TEXTURE_FREE_SAFE(e_data.hammersley);
 	DRW_TEXTURE_FREE_SAFE(e_data.planar_pool_placeholder);
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index a1abb6c71e2..14b0d270dc9 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -78,6 +78,7 @@ typedef struct EEVEE_PassList {
 	struct DRWPass *probe_glossy_compute;
 	struct DRWPass *probe_diffuse_compute;
 	struct DRWPass *probe_display;
+	struct DRWPass *probe_planar_downsample_ps;
 
 	/* Effects */
 	struct DRWPass *motion_blur;
@@ -394,10 +395,13 @@ typedef struct EEVEE_PrivateData {
 	struct DRWShadingGroup *depth_shgrp_clip;
 	struct DRWShadingGroup *depth_shgrp_clip_cull;
 	struct DRWShadingGroup *cube_display_shgrp;
+	struct DRWShadingGroup *planar_downsample;
 	struct GHash *material_hash;
 	struct GHash *hair_material_hash;
 	struct GPUTexture *minmaxz;
 	float background_alpha; /* TODO find a better place for this. */
+	/* For planar probes */
+	float texel_size[2];
 } EEVEE_PrivateData; /* Transient data */
 
 /* eevee_data.c */
@@ -431,7 +435,7 @@ void EEVEE_lights_free(void);
 
 /* eevee_lightprobes.c */
 void EEVEE_lightprobes_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata);
-void EEVEE_lightprobes_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_PassList *psl, EEVEE_StorageList *stl);
+void EEVEE_lightprobes_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_lightprobes_cache_add(EEVEE_SceneLayerData *sldata, Object *ob);
 void EEVEE_lightprobes_cache_finish(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_lightprobes_refresh(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata);
diff --git a/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl b/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
index 2aa51039e71..3327c5c4427 100644
--- a/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
+++ b/source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
@@ -1,5 +1,6 @@
 
 #define M_PI        3.14159265358979323846  /* pi */
+#define M_2PI       6.28318530717958647692  /* 2*pi */
 #define M_PI_2      1.57079632679489661923  /* pi/2 */
 #define M_1_PI      0.318309886183790671538  /* 1/pi */
 #define M_1_2PI     0.159154943091895335768  /* 1/(2*pi) */
diff --git a/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_frag.glsl b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_frag.glsl
new file mode 100644
index 00000000000..fa70fb5590f
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_frag.glsl
@@ -0,0 +1,27 @@
+/**
+ * Simple downsample shader. Takes the average of the 4 texels of lower mip.
+ **/
+
+uniform sampler2DArray source;
+uniform vec2 texelSize;
+
+in vec2 uvs;
+flat in float layer;
+
+out vec4 FragColor;
+
+void main()
+{
+	/* Reconstructing Target uvs like this avoid missing pixels */
+	vec2 uvs = floor(gl_FragCoord.xy) * 2.0 * texelSize + texelSize;
+
+	/* Downsample with a 4x4 box filter */
+	vec4 d = texelSize.xyxy * vec4(-1, -1, +1, +1);
+
+	FragColor  = texture(source, vec3(uvs + d.xy, layer)).rgba;
+	FragColor += texture(source, vec3(uvs + d.zy, layer)).rgba;
+	FragColor += texture(source, vec3(uvs + d.xw, layer)).rgba;
+	FragColor += texture(source, vec3(uvs + d.zw, layer)).rgba;
+
+	FragColor /= 4.0;
+}
\ No newline at end of file
diff --git a/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_geom.glsl b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_geom.glsl
new file mode 100644
index 00000000000..40b04c986f3
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_geom.glsl
@@ -0,0 +1,24 @@
+
+layout(triangles) in;
+layout(triangle_strip, max_vertices=3) out;
+
+in int instance[];
+in vec2 vPos[];
+
+flat out float layer;
+
+void main() {
+	gl_Layer = instance[0];
+	layer = float(instance[0]);
+
+	gl_Position = vec4(vPos[0], 0.0, 0.0);
+	EmitVertex();
+
+	gl_Position = vec4(vPos[1], 0.0, 0.0);
+	EmitVertex();
+
+	gl_Position = vec4(vPos[2], 0.0, 0.0);
+	EmitVertex();
+
+	EndPrimitive();
+}
\ No newline at end of file
diff --git a/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_vert.glsl b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_vert.glsl
new file mode 100644
index 00000000000..ac4e3da4158
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/lightprobe_planar_downsample_vert.glsl
@@ -0,0 +1,10 @@
+
+in vec2 pos;
+
+out int instance;
+out vec2 vPos;
+
+void main() {
+	instance = gl_InstanceID;
+	vPos = pos;
+}
\ No newline at end of file
diff --git a/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl b/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
index 8202acc959a..d6cc170f025 100644
--- a/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
@@ -409,7 +409,21 @@ vec3 eevee_surface_lit(vec3 world_normal, vec3 albedo, vec3 f0, float roughness,
 			refco = pd.reflectionmat * vec4(ref_pos, 1.0);
 			refco.xy /= refco.w;
 
-			vec3 sample = textureLod(probePlanars, vec3(refco.xy, i), 0.0).rgb;
+			/* Distance to roughness */
+			float linear_roughness = sqrt(roughness);
+			float distance_roughness = min(linear_roughness, ref_depth * linear_roughness);
+			linear_roughness = mix(distance_roughness, linear_roughness, linear_roughness);
+
+			/* Decrease influence for high roughness */
+			influ_spec *= saturate((1.0 - linear_roughness) * 5.0 - 2.0);
+
+			float lod = linear_roughness * 2.5 * 5.0;
+			vec3 sample = textureLod(probePlanars, vec3(refco.xy, i), lod).rgb;
+
+			/* Use a second sample randomly rotated to blur out the lowres aspect */
+			vec2 rot_sample = (1.0 / vec2(textureSize(probePlanars, 0).xy)) * vec2(cos(rand.a * M_2PI), sin(rand.a * M_2PI)) * lod;
+			sample += textureLod(probePlanars, vec3(refco.xy + rot_sample, i), lod).rgb;
+			sample *= 0.5;
 
 			spec_accum.rgb += sample * influ_spec;
 			spec_accum.a += influ_spec;