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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * S3 Texture Compression (S3TC) decoding functions |
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| 3 | * Copyright (c) 2007 by Ivo van Poorten |
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| 4 | * |
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| 5 | * see also: http://wiki.multimedia.cx/index.php?title=S3TC |
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| 6 | * |
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| 7 | * This file is part of FFmpeg. |
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| 8 | * |
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| 9 | * FFmpeg is free software; you can redistribute it and/or |
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| 10 | * modify it under the terms of the GNU Lesser General Public |
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| 11 | * License as published by the Free Software Foundation; either |
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| 12 | * version 2.1 of the License, or (at your option) any later version. |
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| 13 | * |
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| 14 | * FFmpeg is distributed in the hope that it will be useful, |
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| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * Lesser General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU Lesser General Public |
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| 20 | * License along with FFmpeg; if not, write to the Free Software |
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| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |||
| 24 | #include "avcodec.h" |
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| 25 | #include "bytestream.h" |
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| 26 | #include "s3tc.h" |
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| 27 | |||
| 28 | static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d, |
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| 29 | unsigned int qstride, unsigned int flag, |
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| 30 | uint64_t alpha) { |
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| 31 | unsigned int x, y, c0, c1, a = (!flag * 255u) << 24; |
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| 32 | unsigned int rb0, rb1, rb2, rb3, g0, g1, g2, g3; |
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| 33 | uint32_t colors[4], pixels; |
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| 34 | |||
| 35 | c0 = bytestream2_get_le16(gb); |
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| 36 | c1 = bytestream2_get_le16(gb); |
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| 37 | |||
| 38 | rb0 = (c0<<3 | c0<<8) & 0xf800f8; |
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| 39 | rb1 = (c1<<3 | c1<<8) & 0xf800f8; |
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| 40 | rb0 += (rb0>>5) & 0x070007; |
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| 41 | rb1 += (rb1>>5) & 0x070007; |
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| 42 | g0 = (c0 <<5) & 0x00fc00; |
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| 43 | g1 = (c1 <<5) & 0x00fc00; |
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| 44 | g0 += (g0 >>6) & 0x000300; |
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| 45 | g1 += (g1 >>6) & 0x000300; |
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| 46 | |||
| 47 | colors[0] = rb0 + g0 + a; |
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| 48 | colors[1] = rb1 + g1 + a; |
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| 49 | |||
| 50 | if (c0 > c1 || flag) { |
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| 51 | rb2 = (((2*rb0+rb1) * 21) >> 6) & 0xff00ff; |
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| 52 | rb3 = (((2*rb1+rb0) * 21) >> 6) & 0xff00ff; |
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| 53 | g2 = (((2*g0 +g1 ) * 21) >> 6) & 0x00ff00; |
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| 54 | g3 = (((2*g1 +g0 ) * 21) >> 6) & 0x00ff00; |
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| 55 | colors[3] = rb3 + g3 + a; |
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| 56 | } else { |
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| 57 | rb2 = ((rb0+rb1) >> 1) & 0xff00ff; |
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| 58 | g2 = ((g0 +g1 ) >> 1) & 0x00ff00; |
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| 59 | colors[3] = 0; |
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| 60 | } |
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| 61 | |||
| 62 | colors[2] = rb2 + g2 + a; |
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| 63 | |||
| 64 | pixels = bytestream2_get_le32(gb); |
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| 65 | for (y=0; y<4; y++) { |
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| 66 | for (x=0; x<4; x++) { |
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| 67 | a = (alpha & 0x0f) << 28; |
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| 68 | a += a >> 4; |
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| 69 | d[x] = a + colors[pixels&3]; |
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| 70 | pixels >>= 2; |
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| 71 | alpha >>= 4; |
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| 72 | } |
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| 73 | d += qstride; |
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| 74 | } |
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| 75 | } |
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| 76 | |||
| 77 | void ff_decode_dxt1(GetByteContext *gb, uint8_t *dst, |
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| 78 | const unsigned int w, const unsigned int h, |
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| 79 | const unsigned int stride) { |
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| 80 | unsigned int bx, by, qstride = stride/4; |
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| 81 | uint32_t *d = (uint32_t *) dst; |
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| 82 | |||
| 83 | for (by=0; by < h/4; by++, d += stride-w) |
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| 84 | for (bx = 0; bx < w / 4; bx++, d += 4) |
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| 85 | dxt1_decode_pixels(gb, d, qstride, 0, 0LL); |
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| 86 | } |
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| 87 | |||
| 88 | void ff_decode_dxt3(GetByteContext *gb, uint8_t *dst, |
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| 89 | const unsigned int w, const unsigned int h, |
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| 90 | const unsigned int stride) { |
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| 91 | unsigned int bx, by, qstride = stride/4; |
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| 92 | uint32_t *d = (uint32_t *) dst; |
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| 93 | |||
| 94 | for (by=0; by < h/4; by++, d += stride-w) |
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| 95 | for (bx = 0; bx < w / 4; bx++, d += 4) |
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| 96 | dxt1_decode_pixels(gb, d, qstride, 1, bytestream2_get_le64(gb)); |
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| 97 | } |