diff options
Diffstat (limited to 'mesalib/src/gallium/auxiliary/util/u_format.h')
| -rw-r--r-- | mesalib/src/gallium/auxiliary/util/u_format.h | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/mesalib/src/gallium/auxiliary/util/u_format.h b/mesalib/src/gallium/auxiliary/util/u_format.h index 4cace6ad1..9774a2b4c 100644 --- a/mesalib/src/gallium/auxiliary/util/u_format.h +++ b/mesalib/src/gallium/auxiliary/util/u_format.h @@ -133,6 +133,7 @@ struct util_format_channel_description unsigned normalized:1; unsigned pure_integer:1; unsigned size:9; /**< bits per channel */ + unsigned shift:16; /** number of bits from lsb */ }; @@ -179,9 +180,31 @@ struct util_format_description unsigned is_mixed:1; /** - * Input channel description. + * Input channel description, in the order XYZW. * * Only valid for UTIL_FORMAT_LAYOUT_PLAIN formats. + * + * If each channel is accessed as an individual N-byte value, X is always + * at the lowest address in memory, Y is always next, and so on. For all + * currently-defined formats, the N-byte value has native endianness. + * + * If instead a group of channels is accessed as a single N-byte value, + * the order of the channels within that value depends on endianness. + * For big-endian targets, X is the most significant subvalue, + * otherwise it is the least significant one. + * + * For example, if X is 8 bits and Y is 24 bits, the memory order is: + * + * 0 1 2 3 + * little-endian: X Yl Ym Yu (l = lower, m = middle, u = upper) + * big-endian: X Yu Ym Yl + * + * If X is 5 bits, Y is 5 bits, Z is 5 bits and W is 1 bit, the layout is: + * + * 0 1 + * msb lsb msb lsb + * little-endian: YYYXXXXX WZZZZZYY + * big-endian: XXXXXYYY YYZZZZZW */ struct util_format_channel_description channel[4]; |