diff options
Diffstat (limited to 'src/intel/isl/isl.c')
| -rw-r--r-- | src/intel/isl/isl.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/intel/isl/isl.c b/src/intel/isl/isl.c index 5cd6ef954a1..7dfead00dc6 100644 --- a/src/intel/isl/isl.c +++ b/src/intel/isl/isl.c @@ -2410,3 +2410,33 @@ isl_swizzle_compose(struct isl_swizzle first, struct isl_swizzle second) .a = swizzle_select(first.a, second), }; } + +/** + * Returns a swizzle that is the pseudo-inverse of this swizzle. + */ +struct isl_swizzle +isl_swizzle_invert(struct isl_swizzle swizzle) +{ + /* Default to zero for channels which do not show up in the swizzle */ + enum isl_channel_select chans[4] = { + ISL_CHANNEL_SELECT_ZERO, + ISL_CHANNEL_SELECT_ZERO, + ISL_CHANNEL_SELECT_ZERO, + ISL_CHANNEL_SELECT_ZERO, + }; + + /* We go in ABGR order so that, if there are any duplicates, the first one + * is taken if you look at it in RGBA order. This is what Haswell hardware + * does for render target swizzles. + */ + if ((unsigned)(swizzle.a - ISL_CHANNEL_SELECT_RED) < 4) + chans[swizzle.a - ISL_CHANNEL_SELECT_RED] = ISL_CHANNEL_SELECT_ALPHA; + if ((unsigned)(swizzle.b - ISL_CHANNEL_SELECT_RED) < 4) + chans[swizzle.b - ISL_CHANNEL_SELECT_RED] = ISL_CHANNEL_SELECT_BLUE; + if ((unsigned)(swizzle.g - ISL_CHANNEL_SELECT_RED) < 4) + chans[swizzle.g - ISL_CHANNEL_SELECT_RED] = ISL_CHANNEL_SELECT_GREEN; + if ((unsigned)(swizzle.r - ISL_CHANNEL_SELECT_RED) < 4) + chans[swizzle.r - ISL_CHANNEL_SELECT_RED] = ISL_CHANNEL_SELECT_RED; + + return (struct isl_swizzle) { chans[0], chans[1], chans[2], chans[3] }; +} |