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-rw-r--r--src/gallium/state_trackers/xa/xa_composite.c34
-rw-r--r--src/gallium/state_trackers/xa/xa_renderer.c6
2 files changed, 29 insertions, 11 deletions
diff --git a/src/gallium/state_trackers/xa/xa_composite.c b/src/gallium/state_trackers/xa/xa_composite.c
index e81eebaf541..bcb27ea1825 100644
--- a/src/gallium/state_trackers/xa/xa_composite.c
+++ b/src/gallium/state_trackers/xa/xa_composite.c
@@ -78,6 +78,27 @@ static const struct xa_composite_blend xa_blends[] = {
0, 0, PIPE_BLENDFACTOR_ONE, PIPE_BLENDFACTOR_ONE},
};
+/*
+ * The alpha value stored in a L8 texture is read by the
+ * hardware as color, and R8 is read as red. The source alpha value
+ * at the end of the fragment shader is stored in all color channels,
+ * so the correct approach is to blend using DST_COLOR instead of
+ * DST_ALPHA and then output any color channel (L8) or the red channel (R8).
+ */
+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,
@@ -111,16 +132,11 @@ blend_for_op(struct xa_composite_blend *blend,
if (!dst_pic->srf)
return supported;
- /*
- * 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;
+ dst_pic->srf->tex->format == PIPE_FORMAT_R8_UNORM)) {
+ blend->rgb_src = xa_convert_blend_for_luminance(blend->rgb_src);
+ blend->rgb_dst = xa_convert_blend_for_luminance(blend->rgb_dst);
+ }
/*
* If there's no dst alpha channel, adjust the blend op so that we'll treat
diff --git a/src/gallium/state_trackers/xa/xa_renderer.c b/src/gallium/state_trackers/xa/xa_renderer.c
index fda07e5b68e..bc55f877c48 100644
--- a/src/gallium/state_trackers/xa/xa_renderer.c
+++ b/src/gallium/state_trackers/xa/xa_renderer.c
@@ -465,9 +465,11 @@ renderer_copy_prepare(struct xa_context *r,
}
/* shaders */
- if (src_texture->format == PIPE_FORMAT_L8_UNORM)
+ if (src_texture->format == PIPE_FORMAT_L8_UNORM ||
+ src_texture->format == PIPE_FORMAT_R8_UNORM)
fs_traits |= FS_SRC_LUMINANCE;
- if (dst_surface->format == PIPE_FORMAT_L8_UNORM)
+ if (dst_surface->format == PIPE_FORMAT_L8_UNORM ||
+ dst_surface->format == PIPE_FORMAT_R8_UNORM)
fs_traits |= FS_DST_LUMINANCE;
if (xa_format_a(dst_xa_format) != 0 &&
xa_format_a(src_xa_format) == 0)