On 09/19/2012 01:27 PM, Kenneth Graunke wrote:
A game we're working with leaves scissoring enabled, but frequently sets
the scissor rectangle to the size of the whole screen. In that case,
scissoring has no effect, so it's safe to go ahead with a fast clear.
Chad believe this should help with Oliver McFadden's "Dante" as well.
v2/Chad: Use the drawbuffer dimensions rather than the miptree slice
dimensions. The miptree slice may be slightly larger due to alignment
restrictions.
There was some question of whether this actually gave any performance
improvement or just made the INTEL_DEBUG=perf warning go away. Can we
see any actual performance delta in Dante?
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
Signed-off-by: Chad Versace <chad.vers...@linux.intel.com>
Cc: Oliver McFadden <oliver.mcfad...@linux.intel.com>
---
src/mesa/drivers/dri/i965/brw_clear.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/src/mesa/drivers/dri/i965/brw_clear.c
b/src/mesa/drivers/dri/i965/brw_clear.c
index c3c75df..625cc85 100644
--- a/src/mesa/drivers/dri/i965/brw_clear.c
+++ b/src/mesa/drivers/dri/i965/brw_clear.c
@@ -77,6 +77,18 @@ debug_mask(const char *name, GLbitfield mask)
}
/**
+ * Returns true if the scissor is a noop (cuts out nothing).
+ */
+static bool
+noop_scissor(struct gl_context *ctx, struct gl_framebuffer *fb)
+{
+ return ctx->Scissor.X <= 0 &&
+ ctx->Scissor.Y <= 0 &&
+ ctx->Scissor.Width >= fb->Width &&
+ ctx->Scissor.Height >= fb->Height;
+}
+
+/**
* Implements fast depth clears on gen6+.
*
* Fast clears basically work by setting a flag in each of the subspans
@@ -110,7 +122,7 @@ brw_fast_clear_depth(struct gl_context *ctx)
* a previous clear had happened at a different clear value and resolve it
* first.
*/
- if (ctx->Scissor.Enabled) {
+ if (ctx->Scissor.Enabled && !noop_scissor(ctx, fb)) {
perf_debug("Failed to fast clear depth due to scissor being enabled. "
"Possible 5%% performance win if avoided.\n");
return false;
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
