Mesa (master): st/mesa: minor optimization in st_DrawBuffers()
Brian Paul
brianp at kemper.freedesktop.org
Thu Apr 13 03:45:05 UTC 2017
Module: Mesa
Branch: master
Commit: c36d224921da0846b808a317d5b71a78b31bfd3d
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=c36d224921da0846b808a317d5b71a78b31bfd3d
Author: Brian Paul <brianp at vmware.com>
Date: Mon Apr 10 21:09:41 2017 -0600
st/mesa: minor optimization in st_DrawBuffers()
We only do on-demand renderbuffer allocation for window-system FBOs,
not user-created FBOs. So put the loop inside a conditional.
Plus, add some comments. No piglit regressions.
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
---
src/mesa/state_tracker/st_cb_fbo.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
index dce4239438..21fc5420d5 100644
--- a/src/mesa/state_tracker/st_cb_fbo.c
+++ b/src/mesa/state_tracker/st_cb_fbo.c
@@ -690,31 +690,39 @@ st_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
/**
- * Called via glDrawBuffer.
+ * Called via glDrawBuffer. We only provide this driver function so that we
+ * can check if we need to allocate a new renderbuffer. Specifically, we
+ * don't usually allocate a front color buffer when using a double-buffered
+ * visual. But if the app calls glDrawBuffer(GL_FRONT) we need to allocate
+ * that buffer. Note, this is only for window system buffers, not user-
+ * created FBOs.
*/
static void
st_DrawBuffers(struct gl_context *ctx, GLsizei count, const GLenum *buffers)
{
struct st_context *st = st_context(ctx);
struct gl_framebuffer *fb = ctx->DrawBuffer;
- GLuint i;
(void) count;
(void) buffers;
- /* add the renderbuffers on demand */
- for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
- GLint idx = fb->_ColorDrawBufferIndexes[i];
+ if (_mesa_is_winsys_fbo(fb)) {
+ GLuint i;
+ /* add the renderbuffers on demand */
+ for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
+ GLint idx = fb->_ColorDrawBufferIndexes[i];
- if (idx >= 0) {
- st_manager_add_color_renderbuffer(st, fb, idx);
+ if (idx >= 0) {
+ st_manager_add_color_renderbuffer(st, fb, idx);
+ }
}
}
}
/**
- * Called via glReadBuffer.
+ * Called via glReadBuffer. As with st_DrawBuffers, we use this function
+ * to check if we need to allocate a renderbuffer on demand.
*/
static void
st_ReadBuffer(struct gl_context *ctx, GLenum buffer)
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