panfrost: Rework format encoding on SFBD

Signed-off-by: Alyssa Rosenzweig <[email protected]>
Signed-off-by: Tomeu Vizoso <[email protected]>
Reviewed-by: Alyssa Rosenzweig <[email protected]>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/gallium/drivers/panfrost/pan_format.c b/src/gallium/drivers/panfrost/pan_format.c
index f272e3a3716..2596b41feac 100644
--- a/src/gallium/drivers/panfrost/pan_format.c
+++ b/src/gallium/drivers/panfrost/pan_format.c
@@ -247,4 +247,26 @@ panfrost_find_format(const struct util_format_description *desc) {
         return (enum mali_format) format;
 }
 
+void
+panfrost_invert_swizzle(const unsigned char *in, unsigned char *out)
+{
+        /* First, default to all zeroes to prevent uninitialized junk */
+
+        for (unsigned c = 0; c < 4; ++c)
+                out[c] = PIPE_SWIZZLE_0;
+
+        /* Now "do" what the swizzle says */
+
+        for (unsigned c = 0; c < 4; ++c) {
+                unsigned char i = in[c];
 
+                /* Who cares? */
+                assert(PIPE_SWIZZLE_X == 0);
+                if (i > PIPE_SWIZZLE_W)
+                        continue;
+
+                /* Invert */
+                unsigned idx = i - PIPE_SWIZZLE_X;
+                out[idx] = PIPE_SWIZZLE_X + c;
+        }
+}