[Bf-blender-cvs] [663d23dd9dc] master: Fix T70463 GPU: Very Slow Workbench/Eevee Performance

[Clément Foucault]

Commit: 663d23dd9dc4801a679b00e5d8ac80483d9b36a8
Author: Clément Foucault
Date:   Fri Oct 4 16:29:41 2019 +0200
Branches: master
https://developer.blender.org/rB663d23dd9dc4801a679b00e5d8ac80483d9b36a8

Fix T70463 GPU: Very Slow Workbench/Eevee Performance

===================================================================

M	source/blender/gpu/intern/gpu_batch.c

===================================================================

diff --git a/source/blender/gpu/intern/gpu_batch.c b/source/blender/gpu/intern/gpu_batch.c
index dcc94cd843c..cffe46f4396 100644
--- a/source/blender/gpu/intern/gpu_batch.c
+++ b/source/blender/gpu/intern/gpu_batch.c
@@ -856,16 +856,19 @@ void GPU_draw_list_submit(GPUDrawList *list)
   uintptr_t offset = list->cmd_offset;
   uint cmd_len = list->cmd_len;
   size_t bytes_used = cmd_len * sizeof(GPUDrawCommandIndexed);
-  list->cmd_offset += bytes_used;
   list->cmd_len = 0; /* Avoid reuse. */
 
-  if (USE_MULTI_DRAW_INDIRECT) {
+  /* Only do multidraw indirect if doing more than 2 drawcall.
+   * This avoids the overhead of buffer mapping if scene is
+   * not very instance friendly. */
+  if (USE_MULTI_DRAW_INDIRECT && cmd_len > 2) {
     GLenum prim = batch->gl_prim_type;
 
     glBindBuffer(GL_DRAW_INDIRECT_BUFFER, list->buffer_id);
     glFlushMappedBufferRange(GL_DRAW_INDIRECT_BUFFER, 0, bytes_used);
     glUnmapBuffer(GL_DRAW_INDIRECT_BUFFER);
     list->commands = NULL; /* Unmapped */
+    list->cmd_offset += bytes_used;
 
     if (batch->elem) {
       glMultiDrawElementsIndirect(prim, INDEX_TYPE(batch->elem), (void *)offset, cmd_len, 0);