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, 13 insertions, 8 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
index d348c5aea8e..9ad302f93ce 100644
--- a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
+++ b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
@@ -186,6 +186,18 @@ void EEVEE_temporal_sampling_reset(EEVEE_Data *vedata)
   vedata->stl->effects->taa_current_sample = 1;
 }
 
+void EEVEE_temporal_sampling_create_view(EEVEE_Data *vedata)
+{
+  EEVEE_EffectsInfo *effects = vedata->stl->effects;
+  /* Create a sub view to disable clipping planes (if any). */
+  const DRWView *default_view = DRW_view_default_get();
+  float viewmat[4][4], winmat[4][4];
+  DRW_view_viewmat_get(default_view, viewmat, false);
+  DRW_view_winmat_get(default_view, winmat, false);
+  effects->taa_view = DRW_view_create_sub(default_view, viewmat, winmat);
+  DRW_view_clip_planes_set(effects->taa_view, NULL, 0);
+}
+
 int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *vedata)
 {
   EEVEE_StorageList *stl = vedata->stl;
@@ -201,15 +213,8 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
    * we accumulate the redraw inside the drawing loop in eevee_draw_scene().
    **/
   effects->taa_render_sample = 1;
-  effects->taa_view = NULL;
 
-  /* Create a sub view to disable clipping planes (if any). */
-  const DRWView *default_view = DRW_view_default_get();
-  float viewmat[4][4], winmat[4][4];
-  DRW_view_viewmat_get(default_view, viewmat, false);
-  DRW_view_winmat_get(default_view, winmat, false);
-  effects->taa_view = DRW_view_create_sub(default_view, viewmat, winmat);
-  DRW_view_clip_planes_set(effects->taa_view, NULL, 0);
+  EEVEE_temporal_sampling_create_view(vedata);
 
   const DRWContextState *draw_ctx = DRW_context_state_get();
   const Scene *scene_eval = DEG_get_evaluated_scene(draw_ctx->depsgraph);