repositories / deb_ffmpeg.git / blame
| Commit | Line | Data |
|---|---|---|
| 2ba45a60 DM |
1 | /* |
| 2 | * S3 Texture Compression (S3TC) decoding functions | |
| 3 | * Copyright (c) 2007 by Ivo van Poorten | |
| 4 | * | |
| 5 | * see also: http://wiki.multimedia.cx/index.php?title=S3TC | |
| 6 | * | |
| 7 | * This file is part of FFmpeg. | |
| 8 | * | |
| 9 | * FFmpeg is free software; you can redistribute it and/or | |
| 10 | * modify it under the terms of the GNU Lesser General Public | |
| 11 | * License as published by the Free Software Foundation; either | |
| 12 | * version 2.1 of the License, or (at your option) any later version. | |
| 13 | * | |
| 14 | * FFmpeg is distributed in the hope that it will be useful, | |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 17 | * Lesser General Public License for more details. | |
| 18 | * | |
| 19 | * You should have received a copy of the GNU Lesser General Public | |
| 20 | * License along with FFmpeg; if not, write to the Free Software | |
| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| 22 | */ | |
| 23 | ||
| 24 | #include "avcodec.h" | |
| 25 | #include "bytestream.h" | |
| 26 | #include "s3tc.h" | |
| 27 | ||
| 28 | static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d, | |
| 29 | unsigned int qstride, unsigned int flag, | |
| 30 | uint64_t alpha) { | |
| 31 | unsigned int x, y, c0, c1, a = (!flag * 255u) << 24; | |
| 32 | unsigned int rb0, rb1, rb2, rb3, g0, g1, g2, g3; | |
| 33 | uint32_t colors[4], pixels; | |
| 34 | ||
| 35 | c0 = bytestream2_get_le16(gb); | |
| 36 | c1 = bytestream2_get_le16(gb); | |
| 37 | ||
| 38 | rb0 = (c0<<3 | c0<<8) & 0xf800f8; | |
| 39 | rb1 = (c1<<3 | c1<<8) & 0xf800f8; | |
| 40 | rb0 += (rb0>>5) & 0x070007; | |
| 41 | rb1 += (rb1>>5) & 0x070007; | |
| 42 | g0 = (c0 <<5) & 0x00fc00; | |
| 43 | g1 = (c1 <<5) & 0x00fc00; | |
| 44 | g0 += (g0 >>6) & 0x000300; | |
| 45 | g1 += (g1 >>6) & 0x000300; | |
| 46 | ||
| 47 | colors[0] = rb0 + g0 + a; | |
| 48 | colors[1] = rb1 + g1 + a; | |
| 49 | ||
| 50 | if (c0 > c1 || flag) { | |
| 51 | rb2 = (((2*rb0+rb1) * 21) >> 6) & 0xff00ff; | |
| 52 | rb3 = (((2*rb1+rb0) * 21) >> 6) & 0xff00ff; | |
| 53 | g2 = (((2*g0 +g1 ) * 21) >> 6) & 0x00ff00; | |
| 54 | g3 = (((2*g1 +g0 ) * 21) >> 6) & 0x00ff00; | |
| 55 | colors[3] = rb3 + g3 + a; | |
| 56 | } else { | |
| 57 | rb2 = ((rb0+rb1) >> 1) & 0xff00ff; | |
| 58 | g2 = ((g0 +g1 ) >> 1) & 0x00ff00; | |
| 59 | colors[3] = 0; | |
| 60 | } | |
| 61 | ||
| 62 | colors[2] = rb2 + g2 + a; | |
| 63 | ||
| 64 | pixels = bytestream2_get_le32(gb); | |
| 65 | for (y=0; y<4; y++) { | |
| 66 | for (x=0; x<4; x++) { | |
| 67 | a = (alpha & 0x0f) << 28; | |
| 68 | a += a >> 4; | |
| 69 | d[x] = a + colors[pixels&3]; | |
| 70 | pixels >>= 2; | |
| 71 | alpha >>= 4; | |
| 72 | } | |
| 73 | d += qstride; | |
| 74 | } | |
| 75 | } | |
| 76 | ||
| 77 | void ff_decode_dxt1(GetByteContext *gb, uint8_t *dst, | |
| 78 | const unsigned int w, const unsigned int h, | |
| 79 | const unsigned int stride) { | |
| 80 | unsigned int bx, by, qstride = stride/4; | |
| 81 | uint32_t *d = (uint32_t *) dst; | |
| 82 | ||
| 83 | for (by=0; by < h/4; by++, d += stride-w) | |
| 84 | for (bx = 0; bx < w / 4; bx++, d += 4) | |
| 85 | dxt1_decode_pixels(gb, d, qstride, 0, 0LL); | |
| 86 | } | |
| 87 | ||
| 88 | void ff_decode_dxt3(GetByteContext *gb, uint8_t *dst, | |
| 89 | const unsigned int w, const unsigned int h, | |
| 90 | const unsigned int stride) { | |
| 91 | unsigned int bx, by, qstride = stride/4; | |
| 92 | uint32_t *d = (uint32_t *) dst; | |
| 93 | ||
| 94 | for (by=0; by < h/4; by++, d += stride-w) | |
| 95 | for (bx = 0; bx < w / 4; bx++, d += 4) | |
| 96 | dxt1_decode_pixels(gb, d, qstride, 1, bytestream2_get_le64(gb)); | |
| 97 | } |