EEVEE: Rework deformation motion blur

This change how motion data are indexed inside the ghash.
We follow cycles closely now and use evaluated ID pointers.

By removing the hack, it fixes T78561 (No Motion Blur on linked objects)

1 files changed, 40 insertions, 31 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_motion_blur.c b/source/blender/draw/engines/eevee/eevee_motion_blur.c
index e3dd4252018..a02007fede9 100644
--- a/source/blender/draw/engines/eevee/eevee_motion_blur.c
+++ b/source/blender/draw/engines/eevee/eevee_motion_blur.c
@@ -289,7 +289,14 @@ void EEVEE_motion_blur_hair_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
     /* Store transform  */
     DRW_hair_duplimat_get(ob, psys, md, mb_data->obmat[mb_step]);
 
-    EEVEE_GeometryMotionData *mb_geom = EEVEE_motion_blur_hair_data_get(&effects->motion_blur, ob);
+    EEVEE_HairMotionData *mb_hair = EEVEE_motion_blur_hair_data_get(&effects->motion_blur, ob);
+    int psys_id = (md != NULL) ? BLI_findindex(&ob->modifiers, md) : 0;
+
+    if (psys_id >= mb_hair->psys_len) {
+      /* This should never happen. It means the modifier list was changed by frame evaluation. */
+      BLI_assert(0);
+      return;
+    }
 
     if (mb_step == MB_CURR) {
       /* Fill missing matrices if the object was hidden in previous or next frame. */
@@ -300,18 +307,21 @@ void EEVEE_motion_blur_hair_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
         copy_m4_m4(mb_data->obmat[MB_NEXT], mb_data->obmat[MB_CURR]);
       }
 
+      GPUTexture *tex_prev = mb_hair->psys[psys_id].hair_pos_tx[MB_PREV];
+      GPUTexture *tex_next = mb_hair->psys[psys_id].hair_pos_tx[MB_NEXT];
+
       grp = DRW_shgroup_hair_create_sub(ob, psys, md, effects->motion_blur.hair_grp);
       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_texture(grp, "prvBuffer", mb_geom->hair_pos_tx[MB_PREV]);
-      DRW_shgroup_uniform_texture(grp, "nxtBuffer", mb_geom->hair_pos_tx[MB_NEXT]);
-      DRW_shgroup_uniform_bool(grp, "useDeform", &mb_geom->use_deform, 1);
+      DRW_shgroup_uniform_texture(grp, "prvBuffer", tex_prev);
+      DRW_shgroup_uniform_texture(grp, "nxtBuffer", tex_next);
+      DRW_shgroup_uniform_bool(grp, "useDeform", &mb_hair->use_deform, 1);
     }
     else {
       /* Store vertex position buffer. */
-      mb_geom->hair_pos[mb_step] = DRW_hair_pos_buffer_get(ob, psys, md);
-      mb_geom->use_deform = true;
+      mb_hair->psys[psys_id].hair_pos[mb_step] = DRW_hair_pos_buffer_get(ob, psys, md);
+      mb_hair->use_deform = true;
     }
   }
 }
@@ -375,17 +385,6 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
       }
 
       if (mb_geom->use_deform) {
-        EEVEE_ObjectEngineData *oedata = EEVEE_object_data_ensure(ob);
-        if (!oedata->geom_update) {
-          /* FIXME(fclem) There can be false positive where the actual mesh is not updated.
-           * This avoids a crash but removes the motion blur from some object.
-           * Maybe an issue with depsgraph tagging. */
-          mb_geom->use_deform = false;
-          oedata->geom_update = false;
-
-          GPU_VERTBUF_DISCARD_SAFE(mb_geom->vbo[MB_PREV]);
-          GPU_VERTBUF_DISCARD_SAFE(mb_geom->vbo[MB_NEXT]);
-        }
         /* Keep to modify later (after init). */
         mb_geom->batch = batch;
       }
@@ -445,29 +444,36 @@ void EEVEE_motion_blur_cache_finish(EEVEE_Data *vedata)
        BLI_ghashIterator_done(&ghi) == false;
        BLI_ghashIterator_step(&ghi)) {
     EEVEE_GeometryMotionData *mb_geom = BLI_ghashIterator_getValue(&ghi);
+    EEVEE_HairMotionData *mb_hair = (EEVEE_HairMotionData *)mb_geom;
 
     if (!mb_geom->use_deform) {
       continue;
     }
 
     switch (mb_geom->type) {
-      case EEVEE_HAIR_GEOM_MOTION_DATA:
+      case EEVEE_MOTION_DATA_HAIR:
         if (mb_step == MB_CURR) {
           /* TODO(fclem) Check if vertex count mismatch. */
-          mb_geom->use_deform = true;
+          mb_hair->use_deform = true;
         }
         else {
-          mb_geom->hair_pos[mb_step] = GPU_vertbuf_duplicate(mb_geom->hair_pos[mb_step]);
+          for (int i = 0; i < mb_hair->psys_len; i++) {
+            if (mb_hair->psys[i].hair_pos[mb_step] == NULL) {
+              continue;
+            }
+            mb_hair->psys[i].hair_pos[mb_step] = GPU_vertbuf_duplicate(
+                mb_hair->psys[i].hair_pos[mb_step]);
 
-          /* Create vbo immediately to bind to texture buffer. */
-          GPU_vertbuf_use(mb_geom->hair_pos[mb_step]);
+            /* Create vbo immediately to bind to texture buffer. */
+            GPU_vertbuf_use(mb_hair->psys[i].hair_pos[mb_step]);
 
-          mb_geom->hair_pos_tx[mb_step] = GPU_texture_create_from_vertbuf(
-              mb_geom->hair_pos[mb_step]);
+            mb_hair->psys[i].hair_pos_tx[mb_step] = GPU_texture_create_from_vertbuf(
+                mb_hair->psys[i].hair_pos[mb_step]);
+          }
         }
         break;
 
-      case EEVEE_MESH_GEOM_MOTION_DATA:
+      case EEVEE_MOTION_DATA_MESH:
         if (mb_step == MB_CURR) {
           /* Modify batch to have data from adjacent frames. */
           GPUBatch *batch = mb_geom->batch;
@@ -549,16 +555,19 @@ void EEVEE_motion_blur_swap_data(EEVEE_Data *vedata)
        BLI_ghashIterator_done(&ghi) == false;
        BLI_ghashIterator_step(&ghi)) {
     EEVEE_GeometryMotionData *mb_geom = BLI_ghashIterator_getValue(&ghi);
+    EEVEE_HairMotionData *mb_hair = (EEVEE_HairMotionData *)mb_geom;
 
     switch (mb_geom->type) {
-      case EEVEE_HAIR_GEOM_MOTION_DATA:
-        GPU_VERTBUF_DISCARD_SAFE(mb_geom->hair_pos[MB_PREV]);
-        DRW_TEXTURE_FREE_SAFE(mb_geom->hair_pos_tx[MB_PREV]);
-        mb_geom->hair_pos[MB_PREV] = mb_geom->hair_pos[MB_NEXT];
-        mb_geom->hair_pos_tx[MB_PREV] = mb_geom->hair_pos_tx[MB_NEXT];
+      case EEVEE_MOTION_DATA_HAIR:
+        for (int i = 0; i < mb_hair->psys_len; i++) {
+          GPU_VERTBUF_DISCARD_SAFE(mb_hair->psys[i].hair_pos[MB_PREV]);
+          DRW_TEXTURE_FREE_SAFE(mb_hair->psys[i].hair_pos_tx[MB_PREV]);
+          mb_hair->psys[i].hair_pos[MB_PREV] = mb_hair->psys[i].hair_pos[MB_NEXT];
+          mb_hair->psys[i].hair_pos_tx[MB_PREV] = mb_hair->psys[i].hair_pos_tx[MB_NEXT];
+        }
         break;
 
-      case EEVEE_MESH_GEOM_MOTION_DATA:
+      case EEVEE_MOTION_DATA_MESH:
         GPU_VERTBUF_DISCARD_SAFE(mb_geom->vbo[MB_PREV]);
         mb_geom->vbo[MB_PREV] = mb_geom->vbo[MB_NEXT];