EEVEE: Motion Blur: Add accumulation motion blur for better precision

This revisit the render pipeline to support time slicing for better motion
blur.

We support accumulation with or without the Post-process motion blur.

If using the post-process, we reuse last step next motion data to avoid
another scene reevaluation.

This also adds support for hair motion blur which is handled in a similar
way as mesh motion blur.

The total number of samples is distributed evenly accross all timesteps to
avoid sampling weighting issues. For this reason, the sample count is
(internally) rounded up to the next multiple of the step count.

Only FX Motion BLur: {F8632258}

FX Motion Blur + 4 time steps: {F8632260}

FX Motion Blur + 32 time steps: {F8632261}

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D8079

1 files changed, 47 insertions, 8 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index a55b15e7d13..156f4a2e706 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -259,6 +259,7 @@ typedef struct EEVEE_PassList {
   struct DRWPass *color_downsample_ps;
   struct DRWPass *color_downsample_cube_ps;
   struct DRWPass *velocity_object;
+  struct DRWPass *velocity_hair;
   struct DRWPass *velocity_resolve;
   struct DRWPass *velocity_tiles_x;
   struct DRWPass *velocity_tiles;
@@ -578,6 +579,7 @@ typedef struct EEVEE_MotionBlurData {
     float persmat[4][4];
     float persinv[4][4];
   } camera[3];
+  DRWShadingGroup *hair_grp;
 } EEVEE_MotionBlurData;
 
 typedef struct EEVEE_ObjectKey {
@@ -593,10 +595,26 @@ typedef struct EEVEE_ObjectMotionData {
   float obmat[3][4][4];
 } EEVEE_ObjectMotionData;
 
+typedef enum eEEVEEMotionData {
+  EEVEE_MESH_GEOM_MOTION_DATA = 0,
+  EEVEE_HAIR_GEOM_MOTION_DATA,
+} eEEVEEMotionData;
+
 typedef struct EEVEE_GeometryMotionData {
-  struct GPUBatch *batch;    /* Batch for time = t. */
-  struct GPUVertBuf *vbo[2]; /* Vbo for time = t +/- step. */
-  int use_deform;            /* To disable deform mb if vertcount mismatch. */
+  eEEVEEMotionData type;
+  int use_deform; /* To disable deform mb if vertcount mismatch. */
+  union {
+    struct {
+      /* Mesh */
+      struct GPUBatch *batch;    /* Batch for time = t. */
+      struct GPUVertBuf *vbo[2]; /* Vbo for time = t +/- step. */
+    };
+    struct {
+      /* Hair */
+      struct GPUVertBuf *hair_pos[2];    /* Position buffer for time = t +/- step. */
+      struct GPUTexture *hair_pos_tx[2]; /* Buffer Texture of the corresponding VBO. */
+    };
+  };
 } EEVEE_GeometryMotionData;
 
 /* ************ EFFECTS DATA ************* */
@@ -667,7 +685,6 @@ typedef struct EEVEE_EffectsInfo {
   float past_world_to_view[4][4];
   CameraParams past_cam_params;
   CameraParams current_cam_params;
-  float motion_blur_sample_offset;
   char motion_blur_step;         /* Which step we are evaluating. */
   int motion_blur_max;           /* Maximum distance in pixels a motion blured pixel can cover. */
   float motion_blur_near_far[2]; /* Camera near/far clip distances (positive). */
@@ -858,6 +875,7 @@ typedef struct EEVEE_ObjectEngineData {
   bool ob_vis, ob_vis_dirty;
 
   bool need_update;
+  bool geom_update;
   uint shadow_caster_id;
 } EEVEE_ObjectEngineData;
 
@@ -933,6 +951,8 @@ typedef struct EEVEE_PrivateData {
   struct DRWView *world_views[6];
   /** For rendering planar reflections. */
   struct DRWView *planar_views[MAX_PLANAR];
+
+  int render_tot_samples;
 } EEVEE_PrivateData; /* Transient data */
 
 /* eevee_data.c */
@@ -944,9 +964,12 @@ EEVEE_ViewLayerData *EEVEE_view_layer_data_ensure_ex(struct ViewLayer *view_laye
 EEVEE_ViewLayerData *EEVEE_view_layer_data_ensure(void);
 EEVEE_ObjectEngineData *EEVEE_object_data_get(Object *ob);
 EEVEE_ObjectEngineData *EEVEE_object_data_ensure(Object *ob);
-EEVEE_ObjectMotionData *EEVEE_motion_blur_object_data_get(EEVEE_MotionBlurData *mb, Object *ob);
+EEVEE_ObjectMotionData *EEVEE_motion_blur_object_data_get(EEVEE_MotionBlurData *mb,
+                                                          Object *ob,
+                                                          bool hair);
 EEVEE_GeometryMotionData *EEVEE_motion_blur_geometry_data_get(EEVEE_MotionBlurData *mb,
-                                                              Object *ob);
+                                                              Object *ob,
+                                                              bool hair);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_get(Object *ob);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_ensure(Object *ob);
 EEVEE_LightEngineData *EEVEE_light_data_get(Object *ob);
@@ -954,6 +977,8 @@ EEVEE_LightEngineData *EEVEE_light_data_ensure(Object *ob);
 EEVEE_WorldEngineData *EEVEE_world_data_get(World *wo);
 EEVEE_WorldEngineData *EEVEE_world_data_ensure(World *wo);
 
+void eevee_id_update(void *vedata, ID *id);
+
 /* eevee_materials.c */
 struct GPUTexture *EEVEE_materials_get_util_tex(void); /* XXX */
 void EEVEE_materials_init(EEVEE_ViewLayerData *sldata,
@@ -1170,10 +1195,16 @@ void EEVEE_subsurface_output_accumulate(EEVEE_ViewLayerData *sldata, EEVEE_Data
 void EEVEE_subsurface_free(void);
 
 /* eevee_motion_blur.c */
-int EEVEE_motion_blur_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, Object *camera);
+int EEVEE_motion_blur_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_motion_blur_step_set(EEVEE_Data *vedata, int step);
 void EEVEE_motion_blur_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, Object *ob);
+void EEVEE_motion_blur_hair_cache_populate(EEVEE_ViewLayerData *sldata,
+                                           EEVEE_Data *vedata,
+                                           Object *ob,
+                                           struct ParticleSystem *psys,
+                                           struct ModifierData *md);
+void EEVEE_motion_blur_swap_data(EEVEE_Data *vedata);
 void EEVEE_motion_blur_cache_finish(EEVEE_Data *vedata);
 void EEVEE_motion_blur_draw(EEVEE_Data *vedata);
 void EEVEE_motion_blur_free(void);
@@ -1201,6 +1232,7 @@ bool EEVEE_renderpasses_only_first_sample_pass_active(EEVEE_Data *vedata);
 
 /* eevee_temporal_sampling.c */
 void EEVEE_temporal_sampling_reset(EEVEE_Data *vedata);
+void EEVEE_temporal_sampling_create_view(EEVEE_Data *vedata);
 int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_temporal_sampling_offset_calc(const double ht_point[2],
                                          const float filter_size,
@@ -1244,6 +1276,10 @@ void EEVEE_effects_free(void);
 bool EEVEE_render_init(EEVEE_Data *vedata,
                        struct RenderEngine *engine,
                        struct Depsgraph *depsgraph);
+void EEVEE_render_view_sync(EEVEE_Data *vedata,
+                            struct RenderEngine *engine,
+                            struct Depsgraph *depsgraph);
+void EEVEE_render_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_render_cache(void *vedata,
                         struct Object *ob,
                         struct RenderEngine *engine,
@@ -1252,10 +1288,13 @@ void EEVEE_render_draw(EEVEE_Data *vedata,
                        struct RenderEngine *engine,
                        struct RenderLayer *render_layer,
                        const struct rcti *rect);
+void EEVEE_render_read_result(EEVEE_Data *vedata,
+                              struct RenderEngine *engine,
+                              struct RenderLayer *rl,
+                              const rcti *rect);
 void EEVEE_render_update_passes(struct RenderEngine *engine,
                                 struct Scene *scene,
                                 struct ViewLayer *view_layer);
-bool EEVEE_render_do_motion_blur(const struct Depsgraph *depsgraph);
 
 /** eevee_lookdev.c */
 void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,