Eevee: SSR: Add fullscreen raytrace.

3 files changed, 36 insertions, 6 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_effects.c b/source/blender/draw/engines/eevee/eevee_effects.c
index fe90534c3cb..6280cdbc522 100644
--- a/source/blender/draw/engines/eevee/eevee_effects.c
+++ b/source/blender/draw/engines/eevee/eevee_effects.c
@@ -84,7 +84,9 @@ static struct {
 
 	/* Screen Space Reflection */
 	struct GPUShader *ssr_raytrace_sh;
+	struct GPUShader *ssr_raytrace_full_sh;
 	struct GPUShader *ssr_resolve_sh;
+	struct GPUShader *ssr_resolve_full_sh;
 
 	/* Simple Downsample */
 	struct GPUShader *downsample_sh;
@@ -192,7 +194,11 @@ void EEVEE_effects_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 		BLI_dynstr_free(ds_frag);
 
 		e_data.ssr_raytrace_sh = DRW_shader_create_fullscreen(ssr_shader_str, SHADER_DEFINES "#define STEP_RAYTRACE\n");
+		e_data.ssr_raytrace_full_sh = DRW_shader_create_fullscreen(ssr_shader_str, SHADER_DEFINES "#define STEP_RAYTRACE\n"
+		                                                                                          "#define FULLRES\n");
 		e_data.ssr_resolve_sh = DRW_shader_create_fullscreen(ssr_shader_str, SHADER_DEFINES "#define STEP_RESOLVE\n");
+		e_data.ssr_resolve_full_sh = DRW_shader_create_fullscreen(ssr_shader_str, SHADER_DEFINES "#define STEP_RESOLVE\n"
+		                                                                                         "#define FULLRES\n");
 
 		MEM_freeN(ssr_shader_str);
 
@@ -537,7 +543,10 @@ void EEVEE_effects_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 		/* Enable double buffering to be able to read previous frame color */
 		effects->enabled_effects |= EFFECT_DOUBLE_BUFFER;
 
-		int tracing_res[2] = {(int)viewport_size[0] / 2, (int)viewport_size[1] / 2};
+		effects->reflection_trace_full = true;
+
+		const int divisor = (effects->reflection_trace_full) ? 1 : 2;
+		int tracing_res[2] = {(int)viewport_size[0] / divisor, (int)viewport_size[1] / divisor};
 		const bool record_two_hit = false;
 		const bool high_qual_input = true; /* TODO dither low quality input */
 
@@ -699,8 +708,11 @@ void EEVEE_effects_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 	}
 
 	if ((effects->enabled_effects & EFFECT_SSR) != 0) {
+		struct GPUShader *trace_shader = (effects->reflection_trace_full) ? e_data.ssr_raytrace_full_sh : e_data.ssr_raytrace_sh;
+		struct GPUShader *resolve_shader = (effects->reflection_trace_full) ? e_data.ssr_resolve_full_sh : e_data.ssr_resolve_sh;
+
 		psl->ssr_raytrace = DRW_pass_create("SSR Raytrace", DRW_STATE_WRITE_COLOR);
-		DRWShadingGroup *grp = DRW_shgroup_create(e_data.ssr_raytrace_sh, psl->ssr_raytrace);
+		DRWShadingGroup *grp = DRW_shgroup_create(trace_shader, psl->ssr_raytrace);
 		DRW_shgroup_uniform_buffer(grp, "depthBuffer", &e_data.depth_src);
 		DRW_shgroup_uniform_buffer(grp, "normalBuffer", &txl->ssr_normal_input);
 		DRW_shgroup_uniform_buffer(grp, "specroughBuffer", &txl->ssr_specrough_input);
@@ -710,7 +722,7 @@ void EEVEE_effects_cache_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 		DRW_shgroup_call_add(grp, quad, NULL);
 
 		psl->ssr_resolve = DRW_pass_create("SSR Resolve", DRW_STATE_WRITE_COLOR | DRW_STATE_ADDITIVE);
-		grp = DRW_shgroup_create(e_data.ssr_resolve_sh, psl->ssr_resolve);
+		grp = DRW_shgroup_create(resolve_shader, psl->ssr_resolve);
 		DRW_shgroup_uniform_buffer(grp, "depthBuffer", &e_data.depth_src);
 		DRW_shgroup_uniform_buffer(grp, "normalBuffer", &txl->ssr_normal_input);
 		DRW_shgroup_uniform_buffer(grp, "specroughBuffer", &txl->ssr_specrough_input);
@@ -1188,7 +1200,9 @@ void EEVEE_effects_free(void)
 {
 	DRW_SHADER_FREE_SAFE(e_data.downsample_sh);
 	DRW_SHADER_FREE_SAFE(e_data.ssr_raytrace_sh);
+	DRW_SHADER_FREE_SAFE(e_data.ssr_raytrace_full_sh);
 	DRW_SHADER_FREE_SAFE(e_data.ssr_resolve_sh);
+	DRW_SHADER_FREE_SAFE(e_data.ssr_resolve_full_sh);
 
 	DRW_SHADER_FREE_SAFE(e_data.volumetric_upsample_sh);
 
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index eec264f1711..22d100ba13e 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -320,6 +320,7 @@ typedef struct EEVEE_EffectsInfo {
 
 	/* SSR */
 	bool use_ssr;
+	bool reflection_trace_full;
 
 	/* Ambient Occlusion */
 	bool use_ao, use_bent_normals;
diff --git a/source/blender/draw/engines/eevee/shaders/effect_ssr_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_ssr_frag.glsl
index e266dac6d22..4473d73c5c8 100644
--- a/source/blender/draw/engines/eevee/shaders/effect_ssr_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/effect_ssr_frag.glsl
@@ -34,15 +34,24 @@ layout(location = 1) out vec4 pdfData;
 
 void main()
 {
+#ifdef FULLRES
+	ivec2 fullres_texel = ivec2(gl_FragCoord.xy);
+	ivec2 halfres_texel = fullres_texel;
+#else
 	ivec2 fullres_texel = ivec2(gl_FragCoord.xy) * 2;
 	ivec2 halfres_texel = ivec2(gl_FragCoord.xy);
+#endif
+
 	float depth = texelFetch(depthBuffer, fullres_texel, 0).r;
 
 	/* Early out */
 	if (depth == 1.0)
 		discard;
 
-	vec2 uvs = gl_FragCoord.xy * 2.0 / vec2(textureSize(depthBuffer, 0));
+	vec2 uvs = gl_FragCoord.xy / vec2(textureSize(depthBuffer, 0));
+#ifndef FULLRES
+	uvs *= 2.0;
+#endif
 
 	/* Using view space */
 	vec3 viewPosition = get_view_space_from_depth(uvs, depth);
@@ -75,8 +84,10 @@ void main()
 
 	/* Raycast over screen */
 	float hit_dist = -1.0;
+	/* Only raytrace if ray is above the surface normal */
+	/* Note : this still fails in some cases like with normal map.
+	 * We should check against the geometric normal but we don't have it at this stage. */
 	if (dot(R, N) > 0.0001) {
-		/* Only raytrace if ray is above the surface normal */
 		hit_dist = raycast(depthBuffer, viewPosition, R);
 	}
 
@@ -195,8 +206,12 @@ float screen_border_mask(vec2 past_hit_co, vec3 hit)
 
 void main()
 {
-	ivec2 halfres_texel = ivec2(gl_FragCoord.xy / 2.0);
 	ivec2 fullres_texel = ivec2(gl_FragCoord.xy);
+#ifdef FULLRES
+	ivec2 halfres_texel = fullres_texel;
+#else
+	ivec2 halfres_texel = ivec2(gl_FragCoord.xy / 2.0);
+#endif
 	vec2 texture_size = vec2(textureSize(depthBuffer, 0));
 	vec2 uvs = gl_FragCoord.xy / texture_size;
 	vec3 rand = texelFetch(utilTex, ivec3(fullres_texel % LUT_SIZE, 2), 0).rba;