Fix T78160 EEVEE: Motion Blur: Bug with Follow Path animation

Follow path seems to not be catched by `BKE_object_moves_in_time`.
For this reason, we cache all transforms for all object and check
ourselves if an animation occurs. This is almost what cycles does.

We also fix the rigid body case if the rigid body use deformation.

1 files changed, 29 insertions, 11 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_motion_blur.c b/source/blender/draw/engines/eevee/eevee_motion_blur.c
index 0d55d92ce6f..400b309de07 100644
--- a/source/blender/draw/engines/eevee/eevee_motion_blur.c
+++ b/source/blender/draw/engines/eevee/eevee_motion_blur.c
@@ -37,6 +37,7 @@
 #include "DNA_mesh_types.h"
 #include "DNA_modifier_types.h"
 #include "DNA_particle_types.h"
+#include "DNA_rigidbody_types.h"
 #include "DNA_screen_types.h"
 
 #include "ED_screen.h"
@@ -329,10 +330,20 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
     return;
   }
 
-  const bool is_dupli = (ob->base_flag & BASE_FROM_DUPLI) != 0;
+  RigidBodyOb *rbo = ob->rigidbody_object;
+
+  /* active rigidbody objects only, as only those are affected by sim. */
+  const bool has_rigidbody = (rbo && (rbo->type == RBO_TYPE_ACTIVE));
+#if 0
   /* For now we assume dupli objects are moving. */
-  const bool object_moves = is_dupli || BKE_object_moves_in_time(ob, true);
-  const bool is_deform = BKE_object_is_deform_modified(DRW_context_state_get()->scene, ob);
+  const bool is_dupli = (ob->base_flag & BASE_FROM_DUPLI) != 0;
+  const bool object_moves = is_dupli || has_rigidbody || BKE_object_moves_in_time(ob, true);
+#else
+  /* BKE_object_moves_in_time does not work in some cases. Better  */
+  const bool object_moves = true;
+#endif
+  const bool is_deform = BKE_object_is_deform_modified(DRW_context_state_get()->scene, ob) ||
+                         (has_rigidbody && (rbo->flag & RBO_FLAG_USE_DEFORM) != 0);
 
   if (!(object_moves || is_deform)) {
     return;
@@ -363,14 +374,6 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
         copy_m4_m4(mb_data->obmat[MB_NEXT], mb_data->obmat[MB_CURR]);
       }
 
-      grp = DRW_shgroup_create(e_data.motion_blur_object_sh, psl->velocity_object);
-      DRW_shgroup_uniform_mat4(grp, "prevModelMatrix", mb_data->obmat[MB_PREV]);
-      DRW_shgroup_uniform_mat4(grp, "currModelMatrix", mb_data->obmat[MB_CURR]);
-      DRW_shgroup_uniform_mat4(grp, "nextModelMatrix", mb_data->obmat[MB_NEXT]);
-      DRW_shgroup_uniform_bool(grp, "useDeform", &mb_geom->use_deform, 1);
-
-      DRW_shgroup_call(grp, batch, ob);
-
       if (mb_geom->use_deform) {
         EEVEE_ObjectEngineData *oedata = EEVEE_object_data_ensure(ob);
         if (!oedata->geom_update) {
@@ -386,6 +389,21 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
         /* Keep to modify later (after init). */
         mb_geom->batch = batch;
       }
+
+      /* Avoid drawing object that has no motions since object_moves is always true. */
+      if (!mb_geom->use_deform && /* Object deformation can happen without transform.  */
+          equals_m4m4(mb_data->obmat[MB_PREV], mb_data->obmat[MB_CURR]) &&
+          equals_m4m4(mb_data->obmat[MB_NEXT], mb_data->obmat[MB_CURR])) {
+        return;
+      }
+
+      grp = DRW_shgroup_create(e_data.motion_blur_object_sh, psl->velocity_object);
+      DRW_shgroup_uniform_mat4(grp, "prevModelMatrix", mb_data->obmat[MB_PREV]);
+      DRW_shgroup_uniform_mat4(grp, "currModelMatrix", mb_data->obmat[MB_CURR]);
+      DRW_shgroup_uniform_mat4(grp, "nextModelMatrix", mb_data->obmat[MB_NEXT]);
+      DRW_shgroup_uniform_bool(grp, "useDeform", &mb_geom->use_deform, 1);
+
+      DRW_shgroup_call(grp, batch, ob);
     }
     else if (is_deform) {
       /* Store vertex position buffer. */