Eevee: TAA Reprojection: Initial implementation

This "improve" the viewport experience by reducing the noise from random
sampling effects (SSAO, Contact Shadows, SSR) when moving the viewport or
during playback.

This does not do Anti Aliasing because this would conflict with the outline
pass. We could enable AA jittering in "only render" mode though.

There are many things to improve but this is a solid basis to build upon.

1 files changed, 83 insertions, 36 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
index acc1bff6331..06f6293240d 100644
--- a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
+++ b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
@@ -27,7 +27,10 @@
 
 #include "DRW_render.h"
 
+#include "ED_screen.h"
+
 #include "BLI_rand.h"
+#include "BLI_string_utils.h"
 
 #include "eevee_private.h"
 #include "GPU_texture.h"
@@ -37,16 +40,29 @@
 static struct {
 	/* Temporal Anti Aliasing */
 	struct GPUShader *taa_resolve_sh;
+	struct GPUShader *taa_resolve_reproject_sh;
 
 	/* Pixel filter table: Only blackman-harris for now. */
 	float inverted_cdf[FILTER_CDF_TABLE_SIZE];
 } e_data = {NULL}; /* Engine data */
 
+extern char datatoc_common_uniforms_lib_glsl[];
+extern char datatoc_common_view_lib_glsl[];
+extern char datatoc_bsdf_common_lib_glsl[];
 extern char datatoc_effect_temporal_aa_glsl[];
 
 static void eevee_create_shader_temporal_sampling(void)
 {
-	e_data.taa_resolve_sh = DRW_shader_create_fullscreen(datatoc_effect_temporal_aa_glsl, NULL);
+	char *frag_str = BLI_string_joinN(
+	        datatoc_common_uniforms_lib_glsl,
+	        datatoc_common_view_lib_glsl,
+	        datatoc_bsdf_common_lib_glsl,
+	        datatoc_effect_temporal_aa_glsl);
+
+	e_data.taa_resolve_sh = DRW_shader_create_fullscreen(frag_str, NULL);
+	e_data.taa_resolve_reproject_sh = DRW_shader_create_fullscreen(frag_str, "#define USE_REPROJECTION\n");
+
+	MEM_freeN(frag_str);
 }
 
 static float UNUSED_FUNCTION(filter_box)(float UNUSED(x))
@@ -163,6 +179,11 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
 	EEVEE_TextureList *txl = vedata->txl;
 	EEVEE_EffectsInfo *effects = stl->effects;
 
+	if (!e_data.taa_resolve_sh) {
+		eevee_create_shader_temporal_sampling();
+		eevee_create_cdf_table_temporal_sampling();
+	}
+
 	/* Reset for each "redraw". When rendering using ogl render,
 	 * we accumulate the redraw inside the drawing loop in eevee_draw_background().
 	 * But we do NOT accumulate between "redraw" (as in full draw manager drawloop)
@@ -173,6 +194,14 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
 	ViewLayer *view_layer = draw_ctx->view_layer;
 	IDProperty *props = BKE_view_layer_engine_evaluated_get(view_layer, COLLECTION_MODE_NONE, RE_engine_id_BLENDER_EEVEE);
 
+	int repro_flag = 0;
+	if (!DRW_state_is_image_render() &&
+		BKE_collection_engine_property_value_get_bool(props, "taa_reprojection"))
+	{
+		repro_flag = EFFECT_TAA_REPROJECT | EFFECT_VELOCITY_BUFFER | EFFECT_DEPTH_DOUBLE_BUFFER | EFFECT_DOUBLE_BUFFER | EFFECT_POST_BUFFER;
+		effects->taa_reproject_sample = ((effects->taa_reproject_sample + 1) % 16);
+	}
+
 	if ((BKE_collection_engine_property_value_get_int(props, "taa_samples") != 1 &&
 	    /* FIXME the motion blur camera evaluation is tagging view_updated
 	     * thus making the TAA always reset and never stopping rendering. */
@@ -181,17 +210,17 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
 	{
 		float persmat[4][4], viewmat[4][4];
 
-		if (!e_data.taa_resolve_sh) {
-			eevee_create_shader_temporal_sampling();
-			eevee_create_cdf_table_temporal_sampling();
-		}
-
 		/* Until we support reprojection, we need to make sure
 		 * that the history buffer contains correct information. */
 		bool view_is_valid = stl->g_data->valid_double_buffer;
 
 		view_is_valid = view_is_valid && (stl->g_data->view_updated == false);
 
+		if (draw_ctx->evil_C != NULL) {
+			struct wmWindowManager *wm = CTX_wm_manager(draw_ctx->evil_C);
+			view_is_valid = view_is_valid && (ED_screen_animation_no_scrub(wm) == NULL);
+		}
+
 		effects->taa_total_sample = BKE_collection_engine_property_value_get_int(props, "taa_samples");
 		MAX2(effects->taa_total_sample, 0);
 
@@ -215,6 +244,7 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
 				/* OGL render already jitter the camera. */
 				if (!DRW_state_is_image_render()) {
 					effects->taa_current_sample += 1;
+					repro_flag = 0;
 
 					double ht_point[2];
 					double ht_offset[2] = {0.0, 0.0};
@@ -238,42 +268,54 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
 			effects->taa_current_sample = 1;
 		}
 
-		DRW_texture_ensure_fullscreen_2D(&txl->depth_double_buffer, DRW_TEX_DEPTH_24_STENCIL_8, 0);
-
-		GPU_framebuffer_ensure_config(&fbl->double_buffer_depth_fb, {
-			GPU_ATTACHMENT_TEXTURE(txl->depth_double_buffer)
-		});
-
-		return EFFECT_TAA | EFFECT_DOUBLE_BUFFER | EFFECT_POST_BUFFER;
+		return repro_flag | EFFECT_TAA | EFFECT_DOUBLE_BUFFER | EFFECT_DEPTH_DOUBLE_BUFFER | EFFECT_POST_BUFFER;
 	}
 
 	effects->taa_current_sample = 1;
 
-	/* Cleanup to release memory */
-	DRW_TEXTURE_FREE_SAFE(txl->depth_double_buffer);
-	GPU_FRAMEBUFFER_FREE_SAFE(fbl->double_buffer_depth_fb);
-
-	return 0;
+	return repro_flag;
 }
 
-void EEVEE_temporal_sampling_cache_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *vedata)
+void EEVEE_temporal_sampling_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
 {
 	EEVEE_PassList *psl = vedata->psl;
 	EEVEE_StorageList *stl = vedata->stl;
 	EEVEE_TextureList *txl = vedata->txl;
 	EEVEE_EffectsInfo *effects = stl->effects;
 
-	if ((effects->enabled_effects & EFFECT_TAA) != 0) {
+	if ((effects->enabled_effects & (EFFECT_TAA | EFFECT_TAA_REPROJECT)) != 0) {
+		struct GPUShader *sh = (effects->enabled_effects & EFFECT_TAA_REPROJECT)
+		                        ? e_data.taa_resolve_reproject_sh
+		                        : e_data.taa_resolve_sh;
+
 		psl->taa_resolve = DRW_pass_create("Temporal AA Resolve", DRW_STATE_WRITE_COLOR);
-		DRWShadingGroup *grp = DRW_shgroup_create(e_data.taa_resolve_sh, psl->taa_resolve);
+		DRWShadingGroup *grp = DRW_shgroup_create(sh, psl->taa_resolve);
 
-		DRW_shgroup_uniform_texture_ref(grp, "historyBuffer", &txl->color_double_buffer);
+		DRW_shgroup_uniform_texture_ref(grp, "colorHistoryBuffer", &txl->color_double_buffer);
 		DRW_shgroup_uniform_texture_ref(grp, "colorBuffer", &txl->color);
-		DRW_shgroup_uniform_float(grp, "alpha", &effects->taa_alpha, 1);
+
+		if (effects->enabled_effects & EFFECT_TAA_REPROJECT) {
+			DefaultTextureList *dtxl = DRW_viewport_texture_list_get();
+			DRW_shgroup_uniform_texture_ref(grp, "velocityBuffer", &effects->velocity_tx);
+			DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
+		}
+		else {
+			DRW_shgroup_uniform_float(grp, "alpha", &effects->taa_alpha, 1);
+		}
 		DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
 	}
 }
 
+/* Special Swap */
+#define SWAP_BUFFER_TAA() do { \
+	SWAP(struct GPUFrameBuffer *, fbl->effect_fb, fbl->double_buffer_fb); \
+	SWAP(struct GPUFrameBuffer *, fbl->effect_color_fb, fbl->double_buffer_color_fb); \
+	SWAP(GPUTexture *, txl->color_post, txl->color_double_buffer); \
+	effects->swap_double_buffer = false; \
+	effects->source_buffer = txl->color_double_buffer; \
+	effects->target_buffer = fbl->main_color_fb; \
+} while (0);
+
 void EEVEE_temporal_sampling_draw(EEVEE_Data *vedata)
 {
 	EEVEE_PassList *psl = vedata->psl;
@@ -282,8 +324,8 @@ void EEVEE_temporal_sampling_draw(EEVEE_Data *vedata)
 	EEVEE_StorageList *stl = vedata->stl;
 	EEVEE_EffectsInfo *effects = stl->effects;
 
-	if ((effects->enabled_effects & EFFECT_TAA) != 0) {
-		if (effects->taa_current_sample != 1) {
+	if ((effects->enabled_effects & (EFFECT_TAA | EFFECT_TAA_REPROJECT)) != 0) {
+		if ((effects->enabled_effects & EFFECT_TAA) != 0 && effects->taa_current_sample != 1) {
 			if (DRW_state_is_image_render()) {
 				/* See EEVEE_temporal_sampling_init() for more details. */
 				effects->taa_alpha = 1.0f / (float)(effects->taa_render_sample);
@@ -300,19 +342,24 @@ void EEVEE_temporal_sampling_draw(EEVEE_Data *vedata)
 				GPU_framebuffer_blit(fbl->double_buffer_depth_fb, 0, fbl->main_fb, 0, GPU_DEPTH_BIT);
 			}
 
-			/* Special Swap */
-			SWAP(struct GPUFrameBuffer *, fbl->effect_fb, fbl->double_buffer_fb);
-			SWAP(struct GPUFrameBuffer *, fbl->effect_color_fb, fbl->double_buffer_color_fb);
-			SWAP(GPUTexture *, txl->color_post, txl->color_double_buffer);
-			effects->swap_double_buffer = false;
-			effects->source_buffer = txl->color_double_buffer;
-			effects->target_buffer = fbl->main_color_fb;
+			SWAP_BUFFER_TAA();
 		}
 		else {
-			/* Save the depth buffer for the next frame.
-			 * This saves us from doing anything special
-			 * in the other mode engines. */
 			if (!DRW_state_is_image_render()) {
+				/* Do reprojection for noise reduction */
+				/* TODO : do AA jitter if in only render view. */
+				if ((effects->enabled_effects & EFFECT_TAA_REPROJECT) != 0 &&
+				    stl->g_data->valid_double_buffer)
+				{
+					GPU_framebuffer_bind(fbl->effect_color_fb);
+					DRW_draw_pass(psl->taa_resolve);
+
+					SWAP_BUFFER_TAA();
+				}
+
+				/* Save the depth buffer for the next frame.
+				 * This saves us from doing anything special
+				 * in the other mode engines. */
 				GPU_framebuffer_blit(fbl->main_fb, 0, fbl->double_buffer_depth_fb, 0, GPU_DEPTH_BIT);
 			}
 		}
@@ -330,10 +377,10 @@ void EEVEE_temporal_sampling_draw(EEVEE_Data *vedata)
 			}
 		}
 	}
-
 }
 
 void EEVEE_temporal_sampling_free(void)
 {
 	DRW_SHADER_FREE_SAFE(e_data.taa_resolve_sh);
+	DRW_SHADER_FREE_SAFE(e_data.taa_resolve_reproject_sh);
 }