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authorEric Anholt <eric@anholt.net>2014-05-21 14:09:25 -0700
committerKenneth Graunke <kenneth@whitecape.org>2014-07-02 12:45:59 -0700
commite874274d0847733b2ae6c2efb911145d2da6e6b6 (patch)
tree8dd3557b8e729a82db4773c6200b9513b0b8c287 /src/mesa/drivers/dri/i965/brw_wm_surface_state.c
parent489ec685542590c7412db81623952c1aa75d946f (diff)
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i965: Add a comment about null renderbuffer surfaces and why they exist.
I noticed this when trying to find comments about pull constant buffers. Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Diffstat (limited to 'src/mesa/drivers/dri/i965/brw_wm_surface_state.c')
-rw-r--r--src/mesa/drivers/dri/i965/brw_wm_surface_state.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
index d3bc797..c0756ad 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -501,6 +501,14 @@ const struct brw_tracked_state brw_wm_pull_constants = {
.emit = brw_upload_wm_pull_constants,
};
+/**
+ * Creates a null renderbuffer surface.
+ *
+ * This is used when the shader doesn't write to any color output. An FB
+ * write to target 0 will still be emitted, because that's how the thread is
+ * terminated (and computed depth is returned), so we need to have the
+ * hardware discard the target 0 color output..
+ */
static void
brw_update_null_renderbuffer_surface(struct brw_context *brw, unsigned int unit)
{