EEEVEE: Object Motion Blur: Initial Implementation

This adds object motion blur vectors for EEVEE as well as better noise
reduction for it.

For TAA reprojection we just compute the motion vector on the fly based on
camera motion and depth buffer. This makes possible to store another motion
vector only for the blurring which is not useful for TAA history fetching.

Motion Data is saved per object & per geometry if using deformation blur.
We support deformation motion blur by saving previous VBO and modifying the
actual GPUBatch for the geometry to include theses VBOs.

We store Previous and Next frame motion in the same motion vector buffer
(RG for prev and BA for next). This makes non linear motion blur (like
rotating objects) less prone to outward/inward blur.

We also improve the motion blur post process to expand outside the objects
border. We use a tile base approach and the max size of the blur is set via
a new render setting.

We use a background reconstruction method that needs another setting
(Background Separation).

Sampling is done using a fixed 8 dithered samples per direction. The final
render samples will clear the noise like other stochastic effects.

One caveat is that hair particles are not yet supported. Support will
come in another patch.

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D7297

1 files changed, 68 insertions, 6 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 40008c5c364..a55b15e7d13 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -29,6 +29,8 @@
 
 #include "DNA_lightprobe_types.h"
 
+#include "BKE_camera.h"
+
 struct EEVEE_ShadowCasterBuffer;
 struct GPUFrameBuffer;
 struct Object;
@@ -256,7 +258,11 @@ typedef struct EEVEE_PassList {
   struct DRWPass *sss_translucency_ps;
   struct DRWPass *color_downsample_ps;
   struct DRWPass *color_downsample_cube_ps;
+  struct DRWPass *velocity_object;
   struct DRWPass *velocity_resolve;
+  struct DRWPass *velocity_tiles_x;
+  struct DRWPass *velocity_tiles;
+  struct DRWPass *velocity_tiles_expand[2];
   struct DRWPass *taa_resolve;
   struct DRWPass *alpha_checker;
 
@@ -327,6 +333,8 @@ typedef struct EEVEE_FramebufferList {
   struct GPUFrameBuffer *renderpass_fb;
   struct GPUFrameBuffer *ao_accum_fb;
   struct GPUFrameBuffer *velocity_resolve_fb;
+  struct GPUFrameBuffer *velocity_fb;
+  struct GPUFrameBuffer *velocity_tiles_fb[2];
 
   struct GPUFrameBuffer *update_noise_fb;
 
@@ -556,6 +564,41 @@ enum {
   PROBE_UPDATE_ALL = 0xFFFFFF,
 };
 
+/* ************** MOTION BLUR ************ */
+
+#define MB_PREV 0
+#define MB_NEXT 1
+#define MB_CURR 2
+
+typedef struct EEVEE_MotionBlurData {
+  struct GHash *object;
+  struct GHash *geom;
+  struct {
+    float viewmat[4][4];
+    float persmat[4][4];
+    float persinv[4][4];
+  } camera[3];
+} EEVEE_MotionBlurData;
+
+typedef struct EEVEE_ObjectKey {
+  /** Object or source object for duplis */
+  struct Object *ob;
+  /** Parent object for duplis */
+  struct Object *parent;
+  /** Dupli objects recursive unique identifier */
+  int id[16]; /* 2*MAX_DUPLI_RECUR */
+} EEVEE_ObjectKey;
+
+typedef struct EEVEE_ObjectMotionData {
+  float obmat[3][4][4];
+} EEVEE_ObjectMotionData;
+
+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. */
+} EEVEE_GeometryMotionData;
+
 /* ************ EFFECTS DATA ************* */
 
 typedef enum EEVEE_EffectsFlag {
@@ -609,7 +652,7 @@ typedef struct EEVEE_EffectsInfo {
   float taa_alpha;
   bool prev_drw_support;
   bool prev_is_navigating;
-  float prev_drw_persmat[4][4];
+  float prev_drw_persmat[4][4]; /* Used for checking view validity and reprojection. */
   struct DRWView *taa_view;
   /* Ambient Occlusion */
   int ao_depth_layer;
@@ -617,15 +660,25 @@ typedef struct EEVEE_EffectsInfo {
   struct GPUTexture *gtao_horizons; /* Textures from pool */
   struct GPUTexture *gtao_horizons_debug;
   /* Motion Blur */
-  float current_world_to_ndc[4][4];
   float current_ndc_to_world[4][4];
+  float current_world_to_ndc[4][4];
+  float current_world_to_view[4][4];
   float past_world_to_ndc[4][4];
-  int motion_blur_samples;
-  bool motion_blur_mat_cached;
+  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). */
+  bool cam_params_init;
+  /* TODO(fclem) Only used in render mode for now.
+   * This is because we are missing a per scene persistent place to hold this. */
+  struct EEVEE_MotionBlurData motion_blur;
   /* Velocity Pass */
-  float velocity_curr_persinv[4][4];
-  float velocity_past_persmat[4][4];
   struct GPUTexture *velocity_tx; /* Texture from pool */
+  struct GPUTexture *velocity_tiles_x_tx;
+  struct GPUTexture *velocity_tiles_tx;
   /* Depth Of Field */
   float dof_near_far[2];
   float dof_params[2];
@@ -883,12 +936,17 @@ typedef struct EEVEE_PrivateData {
 } EEVEE_PrivateData; /* Transient data */
 
 /* eevee_data.c */
+void EEVEE_motion_blur_data_init(EEVEE_MotionBlurData *mb);
+void EEVEE_motion_blur_data_free(EEVEE_MotionBlurData *mb);
 void EEVEE_view_layer_data_free(void *sldata);
 EEVEE_ViewLayerData *EEVEE_view_layer_data_get(void);
 EEVEE_ViewLayerData *EEVEE_view_layer_data_ensure_ex(struct ViewLayer *view_layer);
 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_GeometryMotionData *EEVEE_motion_blur_geometry_data_get(EEVEE_MotionBlurData *mb,
+                                                              Object *ob);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_get(Object *ob);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_ensure(Object *ob);
 EEVEE_LightEngineData *EEVEE_light_data_get(Object *ob);
@@ -1113,7 +1171,10 @@ void EEVEE_subsurface_free(void);
 
 /* eevee_motion_blur.c */
 int EEVEE_motion_blur_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, Object *camera);
+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_cache_finish(EEVEE_Data *vedata);
 void EEVEE_motion_blur_draw(EEVEE_Data *vedata);
 void EEVEE_motion_blur_free(void);
 
@@ -1194,6 +1255,7 @@ void EEVEE_render_draw(EEVEE_Data *vedata,
 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,