On 17/09/15 10:58, Thomas Hellstrom wrote:
On 09/17/2015 11:53 AM, Thomas Hellstrom wrote:
On 09/17/2015 11:34 AM, Jose Fonseca wrote:
On 16/09/15 14:04, Thomas Hellstrom wrote:
XA has been using L8_UNORM for a8 and yuv component surfaces.
This commit instead makes XA prefer R8_UNORM since it's assumed to
have a
higher availability.
Also neither of these formats are suitable as destination formats using
destination alpha blending, so reject those operations.
Signed-off-by: Thomas Hellstrom <thellst...@vmware.com>
---
src/gallium/state_trackers/xa/xa_composite.c | 40
++++++++++------------------
src/gallium/state_trackers/xa/xa_tracker.c | 28 +++++++++++++------
2 files changed, 34 insertions(+), 34 deletions(-)
diff --git a/src/gallium/state_trackers/xa/xa_composite.c
b/src/gallium/state_trackers/xa/xa_composite.c
index 7cfd1e1..e81eeba 100644
--- a/src/gallium/state_trackers/xa/xa_composite.c
+++ b/src/gallium/state_trackers/xa/xa_composite.c
@@ -78,26 +78,6 @@ static const struct xa_composite_blend xa_blends[]
= {
0, 0, PIPE_BLENDFACTOR_ONE, PIPE_BLENDFACTOR_ONE},
};
-
-/*
- * The alpha value stored in a luminance texture is read by the
- * hardware as color.
- */
-static unsigned
-xa_convert_blend_for_luminance(unsigned factor)
-{
- switch(factor) {
- case PIPE_BLENDFACTOR_DST_ALPHA:
- return PIPE_BLENDFACTOR_DST_COLOR;
- case PIPE_BLENDFACTOR_INV_DST_ALPHA:
- return PIPE_BLENDFACTOR_INV_DST_COLOR;
- default:
- break;
- }
- return factor;
-}
-
-
static boolean
blend_for_op(struct xa_composite_blend *blend,
enum xa_composite_op op,
@@ -131,10 +111,16 @@ blend_for_op(struct xa_composite_blend *blend,
if (!dst_pic->srf)
return supported;
- if (dst_pic->srf->tex->format == PIPE_FORMAT_L8_UNORM) {
- blend->rgb_src = xa_convert_blend_for_luminance(blend->rgb_src);
- blend->rgb_dst = xa_convert_blend_for_luminance(blend->rgb_dst);
- }
+ /*
+ * None of the hardware formats we might use for dst A8 are
+ * suitable for dst_alpha blending, since they present the
+ * alpha channel either in all color channels (L8_UNORM) or
+ * in the red channel only (R8_UNORM)
+ */
+ if ((dst_pic->srf->tex->format == PIPE_FORMAT_L8_UNORM ||
+ dst_pic->srf->tex->format == PIPE_FORMAT_R8_UNORM) &&
+ blend->alpha_dst)
+ return FALSE;
I'm not very familiar with this code, but wasn't
xa_convert_blend_for_luminance compensating for the A8 <-> L8
mismatch? It looks like it was doing the right thing. And
xa_convert_blend_for_luminance would work both for L8 and R8.
In these operations since the destination format is A8, we're only
interested in the resulting alpha channel. With
PIPE_BLENDFACTOR_DST_ALPHA, we would use the destination alpha channel
for blending, which would pick up 1 for L8 and R8 which is obviously
wrong. Now the removed function instead set PIPE_BLENDFACTOR_DST_COLOR,
which would, if I read the specs correctly blend component-wise and
yield the correct results for the R, G and B channels if L8 is used. and
for the R channel only if R8 is used. But a prerequisite here is that
the destination logical format is A8 and the alpha channel is never
correct AFAICT.
Hmm, or are you making the point that blending takes place when we've
already swizzled the alpha value to the red channel? Yes, then you're
obviously right, and I need to revert that "fix" ;).
Yeah, my understanding is that we're emulating A8 with L8/R8, hence
logical alpha is in physical red. Hence DST_ALPHA -> DST_RED, etc..
Jose
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
