T54991: Restore support for Motion Path drawing in 2.8

This commit restores support for Motion Path drawing in 2.8 (as it wasn't ported over
to the new draw engines earlier, and the existing space_view3d/drawanimviz.c code was
removed during the Blender Internal removal).

Notes:
* Motion Paths are now implemented as an overlay (enabled by default).
  Therefore, you can turn all of them on/off from the "Overlays" popover

* By and large, we have kept the same draw style as was used in 2.7
  Further changes can happen later following further design work.

* One change from 2.7 is that thicker lines are used by default (2px vs 1px)


Todo's:
* There are some bad-level calls introduced here (i.e. the actgroup_to_keylist() stuff).
  These were introduced to optimise drawing performance (by avoiding full keyframes -> keylist
  conversion step on each drawcall). Instead, this has been moved to the calculation step
  (in blenkernel).  Soon, there will be some cleanups/improvements with those functions,
  so until then, we'll keep the bad level calls.


Credits:
* Clément Foucault (fclem) - Draw Engine magic + Shader Conversion/Optimisation
* Joshua Leung (Aligorith) - COW fixes, UI integration, etc.


Revision History:
See "tmp-b28-motionpath_drawing" branch (rBa12ab5b2ef49ccacae091ccb54d72de0d63f990d)

1 files changed, 24 insertions, 6 deletions

diff --git a/source/blender/draw/intern/draw_manager_data.c b/source/blender/draw/intern/draw_manager_data.c
index 25d720abc71..9b707a81761 100644
--- a/source/blender/draw/intern/draw_manager_data.c
+++ b/source/blender/draw/intern/draw_manager_data.c
@@ -366,6 +366,25 @@ void DRW_shgroup_call_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, float (*obm
 	BLI_LINKS_APPEND(&shgroup->calls, call);
 }
 
+void DRW_shgroup_call_range_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, float (*obmat)[4], uint v_sta, uint v_count)
+{
+	BLI_assert(geom != NULL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
+	BLI_assert(v_count);
+
+	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
+	call->state = drw_call_state_create(shgroup, obmat, NULL);
+	call->type = DRW_CALL_RANGE;
+	call->range.geometry = geom;
+	call->range.start = v_sta;
+	call->range.count = v_count;
+#ifdef USE_GPU_SELECT
+	call->select_id = DST.select_id;
+#endif
+
+	BLI_LINKS_APPEND(&shgroup->calls, call);
+}
+
 static void drw_shgroup_call_procedural_add_ex(
         DRWShadingGroup *shgroup, Gwn_PrimType prim_type, uint vert_count, float (*obmat)[4])
 {
@@ -398,12 +417,11 @@ void DRW_shgroup_call_procedural_triangles_add(DRWShadingGroup *shgroup, uint tr
 	drw_shgroup_call_procedural_add_ex(shgroup, GWN_PRIM_TRIS, tria_count * 3, obmat);
 }
 
-
 /* These calls can be culled and are optimized for redraw */
 void DRW_shgroup_call_object_add_ex(DRWShadingGroup *shgroup, Gwn_Batch *geom, Object *ob, bool bypass_culling)
 {
 	BLI_assert(geom != NULL);
-	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
 
 	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
 	call->state = drw_call_state_object(shgroup, ob->obmat, ob);
@@ -423,7 +441,7 @@ void DRW_shgroup_call_object_add_with_callback(
         DRWCallVisibilityFn *callback, void *user_data)
 {
 	BLI_assert(geom != NULL);
-	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
 
 	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
 	call->state = drw_call_state_object(shgroup, ob->obmat, ob);
@@ -441,7 +459,7 @@ void DRW_shgroup_call_object_add_with_callback(
 void DRW_shgroup_call_instances_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, float (*obmat)[4], uint *count)
 {
 	BLI_assert(geom != NULL);
-	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
 
 	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
 	call->state = drw_call_state_create(shgroup, obmat, NULL);
@@ -459,7 +477,7 @@ void DRW_shgroup_call_instances_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, f
 void DRW_shgroup_call_object_instances_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, Object *ob, uint *count)
 {
 	BLI_assert(geom != NULL);
-	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
 
 	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
 	call->state = drw_call_state_object(shgroup, ob->obmat, ob);
@@ -479,7 +497,7 @@ void DRW_shgroup_call_generate_add(
         float (*obmat)[4])
 {
 	BLI_assert(geometry_fn != NULL);
-	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+	BLI_assert(ELEM(shgroup->type, DRW_SHG_NORMAL, DRW_SHG_FEEDBACK_TRANSFORM));
 
 	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
 	call->state = drw_call_state_create(shgroup, obmat, NULL);