Keep a single OpenGL/GPU context alive on the drawing thread

Avoids expensive context switches.

2 files changed, 29 insertions, 7 deletions

diff --git a/source/blender/draw/DRW_engine.h b/source/blender/draw/DRW_engine.h
index 6c853d27f67..f9963fa67b7 100644
--- a/source/blender/draw/DRW_engine.h
+++ b/source/blender/draw/DRW_engine.h
@@ -171,8 +171,12 @@ void DRW_cache_free_old_batches(struct Main *bmain);
 void DRW_opengl_context_enable_ex(bool restore);
 void DRW_opengl_context_disable_ex(bool restore);
 
+void DRW_opengl_render_context_enable_ex(void *re_gl_context);
 void DRW_opengl_render_context_enable(void *re_gl_context);
+void DRW_opengl_render_context_disable_ex(void *re_gl_context);
 void DRW_opengl_render_context_disable(void *re_gl_context);
+void DRW_render_context_draw_begin();
+void DRW_render_context_draw_end();
 void DRW_gawain_render_context_enable(void *re_gpu_context);
 void DRW_gawain_render_context_disable(void *re_gpu_context);
 
@@ -182,9 +186,7 @@ struct DrawDataList *DRW_drawdatalist_from_id(struct ID *id);
 void DRW_drawdata_free(struct ID *id);
 
 /* select_engine.c */
-void DRW_select_context_create(struct Base **bases,
-                               const uint bases_len,
-                               short select_mode);
+void DRW_select_context_create(struct Base **bases, const uint bases_len, short select_mode);
 bool DRW_select_elem_get(const uint sel_id, uint *r_elem, uint *r_base_index, char *r_elem_type);
 uint DRW_select_context_offset_for_object_elem(const uint base_index, char elem_type);
 uint DRW_select_context_elem_len(void);
diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 26ad9a54189..4b958a74bf9 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -3020,20 +3020,40 @@ void *DRW_gpu_context_get(void)
   return DST.gpu_context;
 }
 
-void DRW_opengl_render_context_enable(void *re_gl_context)
+void DRW_opengl_render_context_enable_ex(void *re_gl_context)
 {
   /* If thread is main you should use DRW_opengl_context_enable(). */
   BLI_assert(!BLI_thread_is_main());
 
-  /* TODO get rid of the blocking. Only here because of the static global DST. */
-  BLI_ticket_mutex_lock(DST.gl_context_mutex);
   WM_opengl_context_activate(re_gl_context);
 }
+void DRW_opengl_render_context_enable(void *re_gl_context)
+{
+  DRW_opengl_render_context_enable_ex(re_gl_context);
+  DRW_render_context_draw_begin();
+}
 
-void DRW_opengl_render_context_disable(void *re_gl_context)
+void DRW_opengl_render_context_disable_ex(void *re_gl_context)
 {
   GPU_flush();
   WM_opengl_context_release(re_gl_context);
+}
+void DRW_opengl_render_context_disable(void *re_gl_context)
+{
+  DRW_opengl_render_context_disable_ex(re_gl_context);
+  DRW_render_context_draw_end();
+}
+
+void DRW_render_context_draw_begin()
+{
+  BLI_assert(!BLI_thread_is_main());
+  /* TODO get rid of the blocking. */
+  BLI_ticket_mutex_lock(DST.gl_context_mutex);
+}
+
+void DRW_render_context_draw_end()
+{
+  //  GPU_flush();
   /* TODO get rid of the blocking. */
   BLI_ticket_mutex_unlock(DST.gl_context_mutex);
 }