DrawManager: Cache material offsets.

When using multiple materials in a single mesh the most time is spend in
counting the offsets of each material for the sorting.

This patch moves the counting of the offsets to render mesh data and
caches it as long as the geometry doesn't change.

This patch doesn't include multithreading of this code.

Reviewed By: mano-wii

Differential Revision: https://developer.blender.org/D11612

1 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract.h b/source/blender/draw/intern/draw_cache_extract.h
index 46234366251..2c4e4dfe76b 100644
--- a/source/blender/draw/intern/draw_cache_extract.h
+++ b/source/blender/draw/intern/draw_cache_extract.h
@@ -83,8 +83,9 @@ typedef enum eMRDataType {
   MR_DATA_LOOPTRI = 1 << 3,
   /** Force loop normals calculation.  */
   MR_DATA_TAN_LOOP_NOR = 1 << 4,
+  MR_DATA_MAT_OFFSETS = 1 << 5,
 } eMRDataType;
-ENUM_OPERATORS(eMRDataType, MR_DATA_TAN_LOOP_NOR)
+ENUM_OPERATORS(eMRDataType, MR_DATA_MAT_OFFSETS)
 
 #ifdef __cplusplus
 extern "C" {
@@ -166,6 +167,12 @@ typedef struct MeshBufferExtractionCache {
     int *verts;
     int *edges;
   } loose_geom;
+
+  struct {
+    int *tri;
+    int visible_tri_len;
+  } mat_offsets;
+
 } MeshBufferExtractionCache;
 
 typedef enum DRWBatchFlag {