[Glamor] [PATCH 6/8] glamor_render: Don't allocate buffer for vbo each time.

[zhigang.gong at linux.intel.com]

From: Zhigang Gong <zhigang.gong at linux.intel.com>

We can reuse the last one if the last one is big enough
to contain current vertext data. In the meantime, Use
MapBufferRange instead of MapBuffer.

Testing shows, this patch brings some benefit for
aa10text/rgb10text. Not too much, but indeed faster.

Signed-off-by: Zhigang Gong <zhigang.gong at linux.intel.com>
---
 src/glamor_render.c |   21 ++++++++++++++++-----
 1 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/glamor_render.c b/src/glamor_render.c
index 9c80cb2..7821d4f 100644
--- a/src/glamor_render.c
+++ b/src/glamor_render.c
@@ -724,10 +724,17 @@ glamor_setup_composite_vbo(ScreenPtr screen, int n_verts)
 	glamor_screen_private *glamor_priv =
 	    glamor_get_screen_private(screen);
 	glamor_gl_dispatch *dispatch;
+	int vert_size;
+	Bool need_new_buffer = FALSE;
 
 	glamor_priv->vbo_offset = 0;
 	glamor_priv->render_nr_verts = 0;
-	glamor_priv->vbo_size = n_verts * sizeof(float) * 2;
+	vert_size = n_verts * sizeof(float) * 2;
+
+	if (glamor_priv->vbo_size < vert_size) {
+		glamor_priv->vbo_size = vert_size;
+		need_new_buffer = TRUE;
+	}
 
 	glamor_priv->vb_stride = 2 * sizeof(float);
 	if (glamor_priv->has_source_coords)
@@ -738,10 +745,14 @@ glamor_setup_composite_vbo(ScreenPtr screen, int n_verts)
 	dispatch = glamor_get_dispatch(glamor_priv);
 	dispatch->glBindBuffer(GL_ARRAY_BUFFER, glamor_priv->vbo);
 	if (glamor_priv->gl_flavor == GLAMOR_GL_DESKTOP) {
-		dispatch->glBufferData(GL_ARRAY_BUFFER,
-				       n_verts * sizeof(float) * 2,
-				       NULL, GL_DYNAMIC_DRAW);
-		glamor_priv->vb = dispatch->glMapBuffer(GL_ARRAY_BUFFER, GL_READ_WRITE);
+		if (need_new_buffer)
+			dispatch->glBufferData(GL_ARRAY_BUFFER,
+					       vert_size,
+					       NULL, GL_DYNAMIC_DRAW);
+		glamor_priv->vb = dispatch->glMapBufferRange(GL_ARRAY_BUFFER, 0,
+						vert_size,
+						GL_MAP_READ_BIT | GL_MAP_WRITE_BIT);
+		assert(glamor_priv->vb != NULL);
 	}
 	dispatch->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, glamor_priv->ebo);
 
-- 
1.7.4.4