Update EXT_texture_compression_bptc.txt
diff --git a/extensions/EXT/EXT_texture_compression_bptc.txt b/extensions/EXT/EXT_texture_compression_bptc.txt index 3842ae9..fe58a78 100644 --- a/extensions/EXT/EXT_texture_compression_bptc.txt +++ b/extensions/EXT/EXT_texture_compression_bptc.txt
@@ -28,8 +28,8 @@ Version - Last Modified Date: April 7, 2017 - Revision: 1 + Last Modified Date: December 10, 2019 + Revision: 2 Number @@ -290,15 +290,16 @@ subset, then green and blue stored similarly. If a block has non-zero alpha bits, the alpha data follows the color data with the same organization. If not, alpha is overridden to 1.0. These bits are treated - as the high bits of a fixed-point value in a byte. If the format has a - shared P-bit, there are two bits for endpoints 0 and 1 from low to - high. If the format has a per-endpoint P-bits, then there are 2*subsets - P-bits stored in the same order as color and alpha. Both kinds of P-bits - are added as a bit below the color data stored in the byte. So, for a - format with 5 red bits, the P-bit ends up in bit 2. For final scaling, the - top bits of the value are replicated into any remaining bits in the - byte. For the preceding example, bits 6 and 7 would be written to bits 0 - and 1. + as the high bits of a fixed-point value in a byte. If the format has + shared P-bits, there are two endpoint bits, the lower of which applies to + both endpoints of subset 0 and the upper of which applies to both + endpoints of subset 1. If the format has a per-endpoint P-bits, then there + are 2*subsets P-bits stored in the same order as color and alpha. Both + kinds of P-bits are added as a bit below the color data stored in the + byte. So, for a format with 5 red bits, the P-bit ends up in bit 2. For + final scaling, the top bits of the value are replicated into any remaining + bits in the byte. For the preceding example, bits 6 and 7 would be written + to bits 0 and 1. The endpoint colors are interpolated using index values stored in the block. The index bits are stored in x-major order. Each index has the @@ -752,6 +753,8 @@ Rev. Date Author Changes ---- -------- ----------- -------------------------------------------- + 2 12/10/19 pdaniell Fix shared p-bits specification to match + DX and the Khronos Data Format spec. + 1 04/10/17 jaschmidt EXT version based on revision 9 of ARB_texture_compression_bptc -