diff options
-rw-r--r-- | libavcodec/s3tc.c | 96 | ||||
-rw-r--r-- | libavcodec/s3tc.h | 36 |
2 files changed, 132 insertions, 0 deletions
diff --git a/libavcodec/s3tc.c b/libavcodec/s3tc.c new file mode 100644 index 0000000..544ee42 --- /dev/null +++ b/libavcodec/s3tc.c @@ -0,0 +1,96 @@ +/* + * S3 Texture Compression (S3TC) decoding functions + * Copyright (c) 2007 by Ivo van Poorten + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * See also: http://wiki.multimedia.cx/index.php?title=S3TC + */ + +#include "avcodec.h" +#include "s3tc.h" + +static inline void dxt1_decode_pixels(const uint8_t *s, uint32_t *d, + unsigned int qstride, unsigned int flag, + uint64_t alpha) { + unsigned int x, y, c0, c1, a = (!flag * 255) << 24; + unsigned int rb0, rb1, rb2, rb3, g0, g1, g2, g3; + uint32_t colors[4], pixels; + + c0 = le2me_16(*(uint16_t *)(s)); + c1 = le2me_16(*(uint16_t *)(s+2)); + + rb0 = (c0<<3 | c0<<8) & 0xf800f8; + rb1 = (c1<<3 | c1<<8) & 0xf800f8; + rb0 += (rb0>>5) & 0x070007; + rb1 += (rb1>>5) & 0x070007; + g0 = (c0 <<5) & 0x00fc00; + g1 = (c1 <<5) & 0x00fc00; + g0 += (g0 >>6) & 0x000300; + g1 += (g1 >>6) & 0x000300; + + colors[0] = rb0 + g0 + a; + colors[1] = rb1 + g1 + a; + + if (c0 > c1 || flag) { + rb2 = (((2*rb0+rb1) * 21) >> 6) & 0xff00ff; + rb3 = (((2*rb1+rb0) * 21) >> 6) & 0xff00ff; + g2 = (((2*g0 +g1 ) * 21) >> 6) & 0x00ff00; + g3 = (((2*g1 +g0 ) * 21) >> 6) & 0x00ff00; + colors[3] = rb3 + g3 + a; + } else { + rb2 = ((rb0+rb1) >> 1) & 0xff00ff; + g2 = ((g0 +g1 ) >> 1) & 0x00ff00; + colors[3] = 0; + } + + colors[2] = rb2 + g2 + a; + + pixels = le2me_32(*(uint32_t *)(s+4)); + for (y=0; y<4; y++) { + for (x=0; x<4; x++) { + a = (alpha & 0x0f) << 28; + a += a >> 4; + d[x] = a + colors[pixels&3]; + pixels >>= 2; + alpha >>= 4; + } + d += qstride; + } +} + +void ff_decode_dxt1(const uint8_t *s, uint8_t *dst, + const unsigned int w, const unsigned int h, + const unsigned int stride) { + unsigned int bx, by, qstride = stride/4; + uint32_t *d = (uint32_t *) dst; + + for (by=0; by < h/4; by++, d += stride-w) + for (bx=0; bx < w/4; bx++, s+=8, d+=4) + dxt1_decode_pixels(s, d, qstride, 0, 0LL); +} + +void ff_decode_dxt3(const uint8_t *s, uint8_t *dst, + const unsigned int w, const unsigned int h, + const unsigned int stride) { + unsigned int bx, by, qstride = stride/4; + uint32_t *d = (uint32_t *) dst; + + for (by=0; by < h/4; by++, d += stride-w) + for (bx=0; bx < w/4; bx++, s+=16, d+=4) + dxt1_decode_pixels(s+8, d, qstride, 1, AV_RL64(s)); +} diff --git a/libavcodec/s3tc.h b/libavcodec/s3tc.h new file mode 100644 index 0000000..ed385ae --- /dev/null +++ b/libavcodec/s3tc.h @@ -0,0 +1,36 @@ +/* + * S3 Texture Compression (S3TC) decoding functions + * Copyright (c) 2007 by Ivo van Poorten + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#ifndef FF_S3TC_H +#define FF_S3TC_H + +#define FF_S3TC_DXT1 0x31545844 +#define FF_S3TC_DXT3 0x33545844 + +void ff_decode_dxt1(const uint8_t *src, uint8_t *dst, + const unsigned int w, const unsigned int h, + const unsigned int stride); +void ff_decode_dxt3(const uint8_t *src, uint8_t *dst, + const unsigned int w, const unsigned int h, + const unsigned int stride); + +#endif |