Sculpt: Rewrite PBVH draw

Rewrite PBVH draw to allocate attributes into individual VBOs.
The old system tried to create a single VBO that could feed
every open viewport.  This required uploading every color and
UV attribute  to the viewport whether needed or not, often exceeding
the VBO limit.

This new system creates one VBO per attribute.  Each attribute layout is
given its own GPU batch which is cached inside the owning PBVH node.

Notes:

* This is a full C++ rewrite.  The old code is still there; ripping it out
can happen later.
* PBVH nodes now have a collection of batches, PBVHBatches, that keeps
track of all the batches inside the node.
* Batches are built exclusively from a list of attributes.
* Each attribute has its own VBO.
* Overlays, workbench and EEVEE can all have different attribute
  layouts, each of which will get its own batch.

Reviewed by: Clement Foucault
Differential Revision: https://developer.blender.org/D15428
Ref D15428

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_customdata.h b/source/blender/blenkernel/BKE_customdata.h
index 22e4a2bce87..0e172abd9a2 100644
--- a/source/blender/blenkernel/BKE_customdata.h
+++ b/source/blender/blenkernel/BKE_customdata.h
@@ -450,6 +450,7 @@ int CustomData_get_stencil_layer(const struct CustomData *data, int type);
  * if no such active layer is defined.
  */
 const char *CustomData_get_active_layer_name(const struct CustomData *data, int type);
+const char *CustomData_get_render_layer_name(const struct CustomData *data, int type);
 
 /**
  * Returns name of the default layer of the given type or NULL