[Bf-blender-cvs] [75de653e4d6] blender2.8: GWN: Batch: Only revert to default Vao when needed.

[Clément Foucault]

Commit: 75de653e4d6204f2fc87388a1c99abcceed04ef1
Author: Clément Foucault
Date:   Wed Mar 14 22:21:59 2018 +0100
Branches: blender2.8
https://developer.blender.org/rB75de653e4d6204f2fc87388a1c99abcceed04ef1

GWN: Batch: Only revert to default Vao when needed.

Drawing ranges via glDrawArrays is already supported and should not need
a manual offset in the VAO like glDrawArraysInstanced or glDrawElements.

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

M	intern/gawain/src/gwn_batch.c

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

diff --git a/intern/gawain/src/gwn_batch.c b/intern/gawain/src/gwn_batch.c
index b7f47b316ed..b447106432c 100644
--- a/intern/gawain/src/gwn_batch.c
+++ b/intern/gawain/src/gwn_batch.c
@@ -529,9 +529,10 @@ void GWN_batch_draw_range_ex(Gwn_Batch* batch, int v_first, int v_count, bool fo
 #if TRUST_NO_ONE
 	assert(!(force_instance && (batch->inst == NULL)) || v_count > 0); // we cannot infer length if force_instance
 #endif
+	const bool do_instance = (force_instance || batch->inst);
 
 	// If using offset drawing, use the default VAO and redo bindings.
-	if (v_first != 0)
+	if (v_first != 0 && (do_instance || batch->elem))
 		{
 		glBindVertexArray(GWN_vao_default());
 		batch_update_program_bindings(batch, v_first);
@@ -539,7 +540,7 @@ void GWN_batch_draw_range_ex(Gwn_Batch* batch, int v_first, int v_count, bool fo
 	else
 		glBindVertexArray(batch->vao_id);
 
-	if (force_instance || batch->inst)
+	if (do_instance)
 		{
 		// Infer length if vertex count is not given
 		if (v_count == 0)
@@ -588,10 +589,9 @@ void GWN_batch_draw_range_ex(Gwn_Batch* batch, int v_first, int v_count, bool fo
 				primitive_restart_disable();
 			}
 		else
-			glDrawArrays(batch->gl_prim_type, 0, v_count);
+			glDrawArrays(batch->gl_prim_type, v_first, v_count);
 		}
 
-
 	glBindVertexArray(0);
 	}