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texturedspenc.c
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1 /*
2  * Texture block compression
3  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
4  * Based on public domain code by Fabian Giesen, Sean Barrett and Yann Collet.
5  *
6  * This file is part of FFmpeg
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a
9  * copy of this software and associated documentation files (the "Software"),
10  * to deal in the Software without restriction, including without limitation
11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12  * and/or sell copies of the Software, and to permit persons to whom the
13  * Software is furnished to do so, subject to the following conditions:
14  * The above copyright notice and this permission notice shall be included
15  * in all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
23  * IN THE SOFTWARE.
24  */
25 
26 #include <stddef.h>
27 #include <stdint.h>
28 
29 #include "libavutil/attributes.h"
30 #include "libavutil/common.h"
31 #include "libavutil/intreadwrite.h"
32 
33 #include "texturedsp.h"
34 
35 static const uint8_t expand5[32] = {
36  0, 8, 16, 24, 33, 41, 49, 57, 66, 74, 82, 90,
37  99, 107, 115, 123, 132, 140, 148, 156, 165, 173, 181, 189,
38  198, 206, 214, 222, 231, 239, 247, 255,
39 };
40 
41 static const uint8_t expand6[64] = {
42  0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44,
43  48, 52, 56, 60, 65, 69, 73, 77, 81, 85, 89, 93,
44  97, 101, 105, 109, 113, 117, 121, 125, 130, 134, 138, 142,
45  146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190,
46  195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239,
47  243, 247, 251, 255,
48 };
49 
50 static const uint8_t match5[256][2] = {
51  { 0, 0 }, { 0, 0 }, { 0, 1 }, { 0, 1 }, { 1, 0 }, { 1, 0 },
52  { 1, 0 }, { 1, 1 }, { 1, 1 }, { 2, 0 }, { 2, 0 }, { 0, 4 },
53  { 2, 1 }, { 2, 1 }, { 2, 1 }, { 3, 0 }, { 3, 0 }, { 3, 0 },
54  { 3, 1 }, { 1, 5 }, { 3, 2 }, { 3, 2 }, { 4, 0 }, { 4, 0 },
55  { 4, 1 }, { 4, 1 }, { 4, 2 }, { 4, 2 }, { 4, 2 }, { 3, 5 },
56  { 5, 1 }, { 5, 1 }, { 5, 2 }, { 4, 4 }, { 5, 3 }, { 5, 3 },
57  { 5, 3 }, { 6, 2 }, { 6, 2 }, { 6, 2 }, { 6, 3 }, { 5, 5 },
58  { 6, 4 }, { 6, 4 }, { 4, 8 }, { 7, 3 }, { 7, 3 }, { 7, 3 },
59  { 7, 4 }, { 7, 4 }, { 7, 4 }, { 7, 5 }, { 5, 9 }, { 7, 6 },
60  { 7, 6 }, { 8, 4 }, { 8, 4 }, { 8, 5 }, { 8, 5 }, { 8, 6 },
61  { 8, 6 }, { 8, 6 }, { 7, 9 }, { 9, 5 }, { 9, 5 }, { 9, 6 },
62  { 8, 8 }, { 9, 7 }, { 9, 7 }, { 9, 7 }, { 10, 6 }, { 10, 6 },
63  { 10, 6 }, { 10, 7 }, { 9, 9 }, { 10, 8 }, { 10, 8 }, { 8, 12 },
64  { 11, 7 }, { 11, 7 }, { 11, 7 }, { 11, 8 }, { 11, 8 }, { 11, 8 },
65  { 11, 9 }, { 9, 13 }, { 11, 10 }, { 11, 10 }, { 12, 8 }, { 12, 8 },
66  { 12, 9 }, { 12, 9 }, { 12, 10 }, { 12, 10 }, { 12, 10 }, { 11, 13 },
67  { 13, 9 }, { 13, 9 }, { 13, 10 }, { 12, 12 }, { 13, 11 }, { 13, 11 },
68  { 13, 11 }, { 14, 10 }, { 14, 10 }, { 14, 10 }, { 14, 11 }, { 13, 13 },
69  { 14, 12 }, { 14, 12 }, { 12, 16 }, { 15, 11 }, { 15, 11 }, { 15, 11 },
70  { 15, 12 }, { 15, 12 }, { 15, 12 }, { 15, 13 }, { 13, 17 }, { 15, 14 },
71  { 15, 14 }, { 16, 12 }, { 16, 12 }, { 16, 13 }, { 16, 13 }, { 16, 14 },
72  { 16, 14 }, { 16, 14 }, { 15, 17 }, { 17, 13 }, { 17, 13 }, { 17, 14 },
73  { 16, 16 }, { 17, 15 }, { 17, 15 }, { 17, 15 }, { 18, 14 }, { 18, 14 },
74  { 18, 14 }, { 18, 15 }, { 17, 17 }, { 18, 16 }, { 18, 16 }, { 16, 20 },
75  { 19, 15 }, { 19, 15 }, { 19, 15 }, { 19, 16 }, { 19, 16 }, { 19, 16 },
76  { 19, 17 }, { 17, 21 }, { 19, 18 }, { 19, 18 }, { 20, 16 }, { 20, 16 },
77  { 20, 17 }, { 20, 17 }, { 20, 18 }, { 20, 18 }, { 20, 18 }, { 19, 21 },
78  { 21, 17 }, { 21, 17 }, { 21, 18 }, { 20, 20 }, { 21, 19 }, { 21, 19 },
79  { 21, 19 }, { 22, 18 }, { 22, 18 }, { 22, 18 }, { 22, 19 }, { 21, 21 },
80  { 22, 20 }, { 22, 20 }, { 20, 24 }, { 23, 19 }, { 23, 19 }, { 23, 19 },
81  { 23, 20 }, { 23, 20 }, { 23, 20 }, { 23, 21 }, { 21, 25 }, { 23, 22 },
82  { 23, 22 }, { 24, 20 }, { 24, 20 }, { 24, 21 }, { 24, 21 }, { 24, 22 },
83  { 24, 22 }, { 24, 22 }, { 23, 25 }, { 25, 21 }, { 25, 21 }, { 25, 22 },
84  { 24, 24 }, { 25, 23 }, { 25, 23 }, { 25, 23 }, { 26, 22 }, { 26, 22 },
85  { 26, 22 }, { 26, 23 }, { 25, 25 }, { 26, 24 }, { 26, 24 }, { 24, 28 },
86  { 27, 23 }, { 27, 23 }, { 27, 23 }, { 27, 24 }, { 27, 24 }, { 27, 24 },
87  { 27, 25 }, { 25, 29 }, { 27, 26 }, { 27, 26 }, { 28, 24 }, { 28, 24 },
88  { 28, 25 }, { 28, 25 }, { 28, 26 }, { 28, 26 }, { 28, 26 }, { 27, 29 },
89  { 29, 25 }, { 29, 25 }, { 29, 26 }, { 28, 28 }, { 29, 27 }, { 29, 27 },
90  { 29, 27 }, { 30, 26 }, { 30, 26 }, { 30, 26 }, { 30, 27 }, { 29, 29 },
91  { 30, 28 }, { 30, 28 }, { 30, 28 }, { 31, 27 }, { 31, 27 }, { 31, 27 },
92  { 31, 28 }, { 31, 28 }, { 31, 28 }, { 31, 29 }, { 31, 29 }, { 31, 30 },
93  { 31, 30 }, { 31, 30 }, { 31, 31 }, { 31, 31 },
94 };
95 
96 static const uint8_t match6[256][2] = {
97  { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 0 }, { 1, 1 }, { 2, 0 },
98  { 2, 1 }, { 3, 0 }, { 3, 0 }, { 3, 1 }, { 4, 0 }, { 4, 0 },
99  { 4, 1 }, { 5, 0 }, { 5, 1 }, { 6, 0 }, { 6, 0 }, { 6, 1 },
100  { 7, 0 }, { 7, 0 }, { 7, 1 }, { 8, 0 }, { 8, 1 }, { 8, 1 },
101  { 8, 2 }, { 9, 1 }, { 9, 2 }, { 9, 2 }, { 9, 3 }, { 10, 2 },
102  { 10, 3 }, { 10, 3 }, { 10, 4 }, { 11, 3 }, { 11, 4 }, { 11, 4 },
103  { 11, 5 }, { 12, 4 }, { 12, 5 }, { 12, 5 }, { 12, 6 }, { 13, 5 },
104  { 13, 6 }, { 8, 16 }, { 13, 7 }, { 14, 6 }, { 14, 7 }, { 9, 17 },
105  { 14, 8 }, { 15, 7 }, { 15, 8 }, { 11, 16 }, { 15, 9 }, { 15, 10 },
106  { 16, 8 }, { 16, 9 }, { 16, 10 }, { 15, 13 }, { 17, 9 }, { 17, 10 },
107  { 17, 11 }, { 15, 16 }, { 18, 10 }, { 18, 11 }, { 18, 12 }, { 16, 16 },
108  { 19, 11 }, { 19, 12 }, { 19, 13 }, { 17, 17 }, { 20, 12 }, { 20, 13 },
109  { 20, 14 }, { 19, 16 }, { 21, 13 }, { 21, 14 }, { 21, 15 }, { 20, 17 },
110  { 22, 14 }, { 22, 15 }, { 25, 10 }, { 22, 16 }, { 23, 15 }, { 23, 16 },
111  { 26, 11 }, { 23, 17 }, { 24, 16 }, { 24, 17 }, { 27, 12 }, { 24, 18 },
112  { 25, 17 }, { 25, 18 }, { 28, 13 }, { 25, 19 }, { 26, 18 }, { 26, 19 },
113  { 29, 14 }, { 26, 20 }, { 27, 19 }, { 27, 20 }, { 30, 15 }, { 27, 21 },
114  { 28, 20 }, { 28, 21 }, { 28, 21 }, { 28, 22 }, { 29, 21 }, { 29, 22 },
115  { 24, 32 }, { 29, 23 }, { 30, 22 }, { 30, 23 }, { 25, 33 }, { 30, 24 },
116  { 31, 23 }, { 31, 24 }, { 27, 32 }, { 31, 25 }, { 31, 26 }, { 32, 24 },
117  { 32, 25 }, { 32, 26 }, { 31, 29 }, { 33, 25 }, { 33, 26 }, { 33, 27 },
118  { 31, 32 }, { 34, 26 }, { 34, 27 }, { 34, 28 }, { 32, 32 }, { 35, 27 },
119  { 35, 28 }, { 35, 29 }, { 33, 33 }, { 36, 28 }, { 36, 29 }, { 36, 30 },
120  { 35, 32 }, { 37, 29 }, { 37, 30 }, { 37, 31 }, { 36, 33 }, { 38, 30 },
121  { 38, 31 }, { 41, 26 }, { 38, 32 }, { 39, 31 }, { 39, 32 }, { 42, 27 },
122  { 39, 33 }, { 40, 32 }, { 40, 33 }, { 43, 28 }, { 40, 34 }, { 41, 33 },
123  { 41, 34 }, { 44, 29 }, { 41, 35 }, { 42, 34 }, { 42, 35 }, { 45, 30 },
124  { 42, 36 }, { 43, 35 }, { 43, 36 }, { 46, 31 }, { 43, 37 }, { 44, 36 },
125  { 44, 37 }, { 44, 37 }, { 44, 38 }, { 45, 37 }, { 45, 38 }, { 40, 48 },
126  { 45, 39 }, { 46, 38 }, { 46, 39 }, { 41, 49 }, { 46, 40 }, { 47, 39 },
127  { 47, 40 }, { 43, 48 }, { 47, 41 }, { 47, 42 }, { 48, 40 }, { 48, 41 },
128  { 48, 42 }, { 47, 45 }, { 49, 41 }, { 49, 42 }, { 49, 43 }, { 47, 48 },
129  { 50, 42 }, { 50, 43 }, { 50, 44 }, { 48, 48 }, { 51, 43 }, { 51, 44 },
130  { 51, 45 }, { 49, 49 }, { 52, 44 }, { 52, 45 }, { 52, 46 }, { 51, 48 },
131  { 53, 45 }, { 53, 46 }, { 53, 47 }, { 52, 49 }, { 54, 46 }, { 54, 47 },
132  { 57, 42 }, { 54, 48 }, { 55, 47 }, { 55, 48 }, { 58, 43 }, { 55, 49 },
133  { 56, 48 }, { 56, 49 }, { 59, 44 }, { 56, 50 }, { 57, 49 }, { 57, 50 },
134  { 60, 45 }, { 57, 51 }, { 58, 50 }, { 58, 51 }, { 61, 46 }, { 58, 52 },
135  { 59, 51 }, { 59, 52 }, { 62, 47 }, { 59, 53 }, { 60, 52 }, { 60, 53 },
136  { 60, 53 }, { 60, 54 }, { 61, 53 }, { 61, 54 }, { 61, 54 }, { 61, 55 },
137  { 62, 54 }, { 62, 55 }, { 62, 55 }, { 62, 56 }, { 63, 55 }, { 63, 56 },
138  { 63, 56 }, { 63, 57 }, { 63, 58 }, { 63, 59 }, { 63, 59 }, { 63, 60 },
139  { 63, 61 }, { 63, 62 }, { 63, 62 }, { 63, 63 },
140 };
141 
142 /* Multiplication over 8 bit emulation */
143 #define mul8(a, b) (((a) * (b) + 128 + (((a) * (b) + 128) >> 8)) >> 8)
144 
145 /* Conversion from rgb24 to rgb565 */
146 #define rgb2rgb565(r, g, b) \
147  ((mul8(r, 31) << 11) | (mul8(g, 63) << 5) | (mul8(b, 31) << 0))
148 
149 /* Linear interpolation at 1/3 point between a and b */
150 #define lerp13(a, b) ((2 * (a) + (b)) / 3)
151 
152 /* Linear interpolation on an RGB pixel */
153 static inline void lerp13rgb(uint8_t *out, uint8_t *p1, uint8_t *p2)
154 {
155  out[0] = lerp13(p1[0], p2[0]);
156  out[1] = lerp13(p1[1], p2[1]);
157  out[2] = lerp13(p1[2], p2[2]);
158 }
159 
160 /* Conversion from rgb565 to rgb24 */
161 static inline void rgb5652rgb(uint8_t *out, uint16_t v)
162 {
163  int rv = (v & 0xf800) >> 11;
164  int gv = (v & 0x07e0) >> 5;
165  int bv = (v & 0x001f) >> 0;
166 
167  out[0] = expand5[rv];
168  out[1] = expand6[gv];
169  out[2] = expand5[bv];
170  out[3] = 0;
171 }
172 
173 /* Color matching function */
174 static unsigned int match_colors(const uint8_t *block, ptrdiff_t stride,
175  uint16_t c0, uint16_t c1)
176 {
177  uint32_t mask = 0;
178  int dirr, dirg, dirb;
179  int dots[16];
180  int stops[4];
181  int x, y, k = 0;
182  int c0_point, half_point, c3_point;
183  uint8_t color[16];
184  const int indexMap[8] = {
185  0 << 30, 2 << 30, 0 << 30, 2 << 30,
186  3 << 30, 3 << 30, 1 << 30, 1 << 30,
187  };
188 
189  /* Fill color and compute direction for each component */
190  rgb5652rgb(color + 0, c0);
191  rgb5652rgb(color + 4, c1);
192  lerp13rgb(color + 8, color + 0, color + 4);
193  lerp13rgb(color + 12, color + 4, color + 0);
194 
195  dirr = color[0 * 4 + 0] - color[1 * 4 + 0];
196  dirg = color[0 * 4 + 1] - color[1 * 4 + 1];
197  dirb = color[0 * 4 + 2] - color[1 * 4 + 2];
198 
199  for (y = 0; y < 4; y++) {
200  for (x = 0; x < 4; x++)
201  dots[k++] = block[0 + x * 4 + y * stride] * dirr +
202  block[1 + x * 4 + y * stride] * dirg +
203  block[2 + x * 4 + y * stride] * dirb;
204 
205  stops[y] = color[0 + y * 4] * dirr +
206  color[1 + y * 4] * dirg +
207  color[2 + y * 4] * dirb;
208  }
209 
210  /* Think of the colors as arranged on a line; project point onto that line,
211  * then choose next color out of available ones. we compute the crossover
212  * points for 'best color in top half'/'best in bottom half' and then
213  * the same inside that subinterval.
214  *
215  * Relying on this 1d approximation isn't always optimal in terms of
216  * euclidean distance, but it's very close and a lot faster.
217  *
218  * http://cbloomrants.blogspot.com/2008/12/12-08-08-dxtc-summary.html */
219  c0_point = (stops[1] + stops[3]) >> 1;
220  half_point = (stops[3] + stops[2]) >> 1;
221  c3_point = (stops[2] + stops[0]) >> 1;
222 
223  for (x = 0; x < 16; x++) {
224  int dot = dots[x];
225  int bits = (dot < half_point ? 4 : 0) |
226  (dot < c0_point ? 2 : 0) |
227  (dot < c3_point ? 1 : 0);
228 
229  mask >>= 2;
230  mask |= indexMap[bits];
231  }
232 
233  return mask;
234 }
235 
236 /* Color optimization function */
237 static void optimize_colors(const uint8_t *block, ptrdiff_t stride,
238  uint16_t *pmax16, uint16_t *pmin16)
239 {
240  const uint8_t *minp;
241  const uint8_t *maxp;
242  const int iter_power = 4;
243  double magn;
244  int v_r, v_g, v_b;
245  float covf[6], vfr, vfg, vfb;
246  int mind, maxd;
247  int cov[6] = { 0 };
248  int mu[3], min[3], max[3];
249  int ch, iter, x, y;
250 
251  /* Determine color distribution */
252  for (ch = 0; ch < 3; ch++) {
253  const uint8_t *bp = &block[ch];
254  int muv, minv, maxv;
255 
256  muv = minv = maxv = bp[0];
257  for (y = 0; y < 4; y++) {
258  for (x = 4; x < 4; x += 4) {
259  muv += bp[x * 4 + y * stride];
260  if (bp[x] < minv)
261  minv = bp[x * 4 + y * stride];
262  else if (bp[x] > maxv)
263  maxv = bp[x * 4 + y * stride];
264  }
265  }
266 
267  mu[ch] = (muv + 8) >> 4;
268  min[ch] = minv;
269  max[ch] = maxv;
270  }
271 
272  /* Determine covariance matrix */
273  for (y = 0; y < 4; y++) {
274  for (x = 0; x < 4; x++) {
275  int r = block[x * 4 + stride * y + 0] - mu[0];
276  int g = block[x * 4 + stride * y + 1] - mu[1];
277  int b = block[x * 4 + stride * y + 2] - mu[2];
278 
279  cov[0] += r * r;
280  cov[1] += r * g;
281  cov[2] += r * b;
282  cov[3] += g * g;
283  cov[4] += g * b;
284  cov[5] += b * b;
285  }
286  }
287 
288  /* Convert covariance matrix to float, find principal axis via power iter */
289  for (x = 0; x < 6; x++)
290  covf[x] = cov[x] / 255.0f;
291 
292  vfr = (float) (max[0] - min[0]);
293  vfg = (float) (max[1] - min[1]);
294  vfb = (float) (max[2] - min[2]);
295 
296  for (iter = 0; iter < iter_power; iter++) {
297  float r = vfr * covf[0] + vfg * covf[1] + vfb * covf[2];
298  float g = vfr * covf[1] + vfg * covf[3] + vfb * covf[4];
299  float b = vfr * covf[2] + vfg * covf[4] + vfb * covf[5];
300 
301  vfr = r;
302  vfg = g;
303  vfb = b;
304  }
305 
306  magn = fabs(vfr);
307  if (fabs(vfg) > magn)
308  magn = fabs(vfg);
309  if (fabs(vfb) > magn)
310  magn = fabs(vfb);
311 
312  /* if magnitudo is too small, default to luminance */
313  if (magn < 4.0f) {
314  /* JPEG YCbCr luma coefs, scaled by 1000 */
315  v_r = 299;
316  v_g = 587;
317  v_b = 114;
318  } else {
319  magn = 512.0 / magn;
320  v_r = (int) (vfr * magn);
321  v_g = (int) (vfg * magn);
322  v_b = (int) (vfb * magn);
323  }
324 
325  /* Pick colors at extreme points */
326  mind = maxd = block[0] * v_r + block[1] * v_g + block[2] * v_b;
327  minp = maxp = block;
328  for (y = 0; y < 4; y++) {
329  for (x = 0; x < 4; x++) {
330  int dot = block[x * 4 + y * stride + 0] * v_r +
331  block[x * 4 + y * stride + 1] * v_g +
332  block[x * 4 + y * stride + 2] * v_b;
333 
334  if (dot < mind) {
335  mind = dot;
336  minp = block + x * 4 + y * stride;
337  } else if (dot > maxd) {
338  maxd = dot;
339  maxp = block + x * 4 + y * stride;
340  }
341  }
342  }
343 
344  *pmax16 = rgb2rgb565(maxp[0], maxp[1], maxp[2]);
345  *pmin16 = rgb2rgb565(minp[0], minp[1], minp[2]);
346 }
347 
348 /* Try to optimize colors to suit block contents better, by solving
349  * a least squares system via normal equations + Cramer's rule. */
350 static int refine_colors(const uint8_t *block, ptrdiff_t stride,
351  uint16_t *pmax16, uint16_t *pmin16, uint32_t mask)
352 {
353  uint32_t cm = mask;
354  uint16_t oldMin = *pmin16;
355  uint16_t oldMax = *pmax16;
356  uint16_t min16, max16;
357  int x, y;
358 
359  /* Additional magic to save a lot of multiplies in the accumulating loop.
360  * The tables contain precomputed products of weights for least squares
361  * system, accumulated inside one 32-bit register */
362  const int w1tab[4] = { 3, 0, 2, 1 };
363  const int prods[4] = { 0x090000, 0x000900, 0x040102, 0x010402 };
364 
365  /* Check if all pixels have the same index */
366  if ((mask ^ (mask << 2)) < 4) {
367  /* If so, linear system would be singular; solve using optimal
368  * single-color match on average color. */
369  int r = 8, g = 8, b = 8;
370  for (y = 0; y < 4; y++) {
371  for (x = 0; x < 4; x++) {
372  r += block[0 + x * 4 + y * stride];
373  g += block[1 + x * 4 + y * stride];
374  b += block[2 + x * 4 + y * stride];
375  }
376  }
377 
378  r >>= 4;
379  g >>= 4;
380  b >>= 4;
381 
382  max16 = (match5[r][0] << 11) | (match6[g][0] << 5) | match5[b][0];
383  min16 = (match5[r][1] << 11) | (match6[g][1] << 5) | match5[b][1];
384  } else {
385  float fr, fg, fb;
386  int at1_r = 0, at1_g = 0, at1_b = 0;
387  int at2_r = 0, at2_g = 0, at2_b = 0;
388  int akku = 0;
389  int xx, xy, yy;
390 
391  for (y = 0; y < 4; y++) {
392  for (x = 0; x < 4; x++) {
393  int step = cm & 3;
394  int w1 = w1tab[step];
395  int r = block[0 + x * 4 + y * stride];
396  int g = block[1 + x * 4 + y * stride];
397  int b = block[2 + x * 4 + y * stride];
398 
399  akku += prods[step];
400  at1_r += w1 * r;
401  at1_g += w1 * g;
402  at1_b += w1 * b;
403  at2_r += r;
404  at2_g += g;
405  at2_b += b;
406 
407  cm >>= 2;
408  }
409  }
410 
411  at2_r = 3 * at2_r - at1_r;
412  at2_g = 3 * at2_g - at1_g;
413  at2_b = 3 * at2_b - at1_b;
414 
415  /* Extract solutions and decide solvability */
416  xx = akku >> 16;
417  yy = (akku >> 8) & 0xFF;
418  xy = (akku >> 0) & 0xFF;
419 
420  fr = 3.0f * 31.0f / 255.0f / (xx * yy - xy * xy);
421  fg = fr * 63.0f / 31.0f;
422  fb = fr;
423 
424  /* Solve */
425  max16 = av_clip_uintp2((at1_r * yy - at2_r * xy) * fr + 0.5f, 5) << 11;
426  max16 |= av_clip_uintp2((at1_g * yy - at2_g * xy) * fg + 0.5f, 6) << 5;
427  max16 |= av_clip_uintp2((at1_b * yy - at2_b * xy) * fb + 0.5f, 5) << 0;
428 
429  min16 = av_clip_uintp2((at2_r * xx - at1_r * xy) * fr + 0.5f, 5) << 11;
430  min16 |= av_clip_uintp2((at2_g * xx - at1_g * xy) * fg + 0.5f, 6) << 5;
431  min16 |= av_clip_uintp2((at2_b * xx - at1_b * xy) * fb + 0.5f, 5) << 0;
432  }
433 
434  *pmin16 = min16;
435  *pmax16 = max16;
436  return oldMin != min16 || oldMax != max16;
437 }
438 
439 /* Check if input block is a constant color */
440 static int constant_color(const uint8_t *block, ptrdiff_t stride)
441 {
442  int x, y;
443  uint32_t first = AV_RL32(block);
444 
445  for (y = 0; y < 4; y++)
446  for (x = 0; x < 4; x++)
447  if (first != AV_RL32(block + x * 4 + y * stride))
448  return 0;
449  return 1;
450 }
451 
452 /* Main color compression function */
453 static void compress_color(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
454 {
455  uint32_t mask;
456  uint16_t max16, min16;
457  int constant = constant_color(block, stride);
458 
459  /* Constant color will load values from tables */
460  if (constant) {
461  int r = block[0];
462  int g = block[1];
463  int b = block[2];
464  mask = 0xAAAAAAAA;
465  max16 = (match5[r][0] << 11) | (match6[g][0] << 5) | match5[b][0];
466  min16 = (match5[r][1] << 11) | (match6[g][1] << 5) | match5[b][1];
467  } else {
468  int refine;
469 
470  /* Otherwise find pca and map along principal axis */
471  optimize_colors(block, stride, &max16, &min16);
472  if (max16 != min16)
473  mask = match_colors(block, stride, max16, min16);
474  else
475  mask = 0;
476 
477  /* One pass refinement */
478  refine = refine_colors(block, stride, &max16, &min16, mask);
479  if (refine) {
480  if (max16 != min16)
481  mask = match_colors(block, stride, max16, min16);
482  else
483  mask = 0;
484  }
485  }
486 
487  /* Finally write the color block */
488  if (max16 < min16) {
489  FFSWAP(uint16_t, min16, max16);
490  mask ^= 0x55555555;
491  }
492 
493  AV_WL16(dst + 0, max16);
494  AV_WL16(dst + 2, min16);
495  AV_WL32(dst + 4, mask);
496 }
497 
498 /* Alpha compression function */
499 static void compress_alpha(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
500 {
501  int x, y;
502  int dist, bias, dist4, dist2;
503  int mn, mx;
504  int bits = 0;
505  int mask = 0;
506 
507  memset(dst, 0, 8);
508 
509  /* Find min/max color */
510  mn = mx = block[3];
511  for (y = 0; y < 4; y++) {
512  for (x = 0; x < 4; x++) {
513  int val = block[3 + x * 4 + y * stride];
514  if (val < mn)
515  mn = val;
516  else if (val > mx)
517  mx = val;
518  }
519  }
520 
521  /* Encode them */
522  dst[0] = (uint8_t) mx;
523  dst[1] = (uint8_t) mn;
524  dst += 2;
525 
526  /* Mono-alpha shortcut */
527  if (mn == mx)
528  return;
529 
530  /* Determine bias and emit color indices.
531  * Given the choice of mx/mn, these indices are optimal:
532  * fgiesen.wordpress.com/2009/12/15/dxt5-alpha-block-index-determination */
533  dist = mx - mn;
534 
535  dist4 = dist * 4;
536  dist2 = dist * 2;
537  if (dist < 8)
538  bias = dist - 1 - mn * 7;
539  else
540  bias = dist / 2 + 2 - mn * 7;
541 
542  for (y = 0; y < 4; y++) {
543  for (x = 0; x < 4; x++) {
544  int alp = block[3 + x * 4 + y * stride] * 7 + bias;
545  int ind, tmp;
546 
547  /* This is a "linear scale" lerp factor between 0 (val=min)
548  * and 7 (val=max) to select index. */
549  tmp = (alp >= dist4) ? -1 : 0;
550  ind = tmp & 4;
551  alp -= dist4 & tmp;
552  tmp = (alp >= dist2) ? -1 : 0;
553  ind += tmp & 2;
554  alp -= dist2 & tmp;
555  ind += (alp >= dist);
556 
557  /* Turn linear scale into DXT index (0/1 are extreme points) */
558  ind = -ind & 7;
559  ind ^= (2 > ind);
560 
561  /* Write index */
562  mask |= ind << bits;
563  bits += 3;
564  if (bits >= 8) {
565  *dst++ = mask;
566  mask >>= 8;
567  bits -= 8;
568  }
569  }
570  }
571 }
572 
573 /**
574  * Convert a RGBA buffer to unscaled YCoCg.
575  * Scale is usually introduced to avoid banding over a certain range of colors,
576  * but this version of the algorithm does not introduce it as much as other
577  * implementations, allowing for a simpler and faster conversion.
578  */
579 static void rgba2ycocg(uint8_t *dst, const uint8_t *pixel)
580 {
581  int r = pixel[0];
582  int g = (pixel[1] + 1) >> 1;
583  int b = pixel[2];
584  int t = (2 + r + b) >> 2;
585 
586  dst[0] = av_clip_uint8(128 + ((r - b + 1) >> 1)); /* Co */
587  dst[1] = av_clip_uint8(128 + g - t); /* Cg */
588  dst[2] = 0;
589  dst[3] = av_clip_uint8(g + t); /* Y */
590 }
591 
592 /**
593  * Compress one block of RGBA pixels in a DXT1 texture and store the
594  * resulting bytes in 'dst'. Alpha is not preserved.
595  *
596  * @param dst output buffer.
597  * @param stride scanline in bytes.
598  * @param block block to compress.
599  * @return how much texture data has been written.
600  */
601 static int dxt1_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
602 {
603  compress_color(dst, stride, block);
604 
605  return 8;
606 }
607 
608 /**
609  * Compress one block of RGBA pixels in a DXT5 texture and store the
610  * resulting bytes in 'dst'. Alpha is preserved.
611  *
612  * @param dst output buffer.
613  * @param stride scanline in bytes.
614  * @param block block to compress.
615  * @return how much texture data has been written.
616  */
617 static int dxt5_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
618 {
619  compress_alpha(dst, stride, block);
620  compress_color(dst + 8, stride, block);
621 
622  return 16;
623 }
624 
625 /**
626  * Compress one block of RGBA pixels in a DXT5-YCoCg texture and store the
627  * resulting bytes in 'dst'. Alpha is not preserved.
628  *
629  * @param dst output buffer.
630  * @param stride scanline in bytes.
631  * @param block block to compress.
632  * @return how much texture data has been written.
633  */
634 static int dxt5ys_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
635 {
636  int x, y;
637  uint8_t reorder[64];
638 
639  /* Reorder the components and then run a normal DXT5 compression. */
640  for (y = 0; y < 4; y++)
641  for (x = 0; x < 4; x++)
642  rgba2ycocg(reorder + x * 4 + y * 16, block + x * 4 + y * stride);
643 
644  compress_alpha(dst + 0, 16, reorder);
645  compress_color(dst + 8, 16, reorder);
646 
647  return 16;
648 }
649 
651 {
652  c->dxt1_block = dxt1_block;
653  c->dxt5_block = dxt5_block;
655 }
static int dxt5ys_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Compress one block of RGBA pixels in a DXT5-YCoCg texture and store the resulting bytes in 'dst'...
static int dxt5_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Compress one block of RGBA pixels in a DXT5 texture and store the resulting bytes in 'dst'...
const char const char void * val
Definition: avisynth_c.h:634
static void rgb5652rgb(uint8_t *out, uint16_t v)
int(* dxt1_block)(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Definition: texturedsp.h:46
const char * g
Definition: vf_curves.c:108
static int constant_color(const uint8_t *block, ptrdiff_t stride)
Texture block (4x4) module.
const char * b
Definition: vf_curves.c:109
static int refine_colors(const uint8_t *block, ptrdiff_t stride, uint16_t *pmax16, uint16_t *pmin16, uint32_t mask)
av_cold void ff_texturedspenc_init(TextureDSPContext *c)
Macro definitions for various function/variable attributes.
uint8_t bits
Definition: crc.c:295
uint8_t
#define av_cold
Definition: attributes.h:82
static const uint64_t c1
Definition: murmur3.c:49
static void rgba2ycocg(uint8_t *dst, const uint8_t *pixel)
Convert a RGBA buffer to unscaled YCoCg.
#define cm
Definition: dvbsubdec.c:36
static int dxt1_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Compress one block of RGBA pixels in a DXT1 texture and store the resulting bytes in 'dst'...
static const uint8_t match5[256][2]
Definition: texturedspenc.c:50
#define rgb2rgb565(r, g, b)
static const uint16_t mask[17]
Definition: lzw.c:38
const char * r
Definition: vf_curves.c:107
int(* dxt5_block)(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Definition: texturedsp.h:51
static void lerp13rgb(uint8_t *out, uint8_t *p1, uint8_t *p2)
FILE * out
Definition: movenc-test.c:54
static unsigned int match_colors(const uint8_t *block, ptrdiff_t stride, uint16_t c0, uint16_t c1)
static void optimize_colors(const uint8_t *block, ptrdiff_t stride, uint16_t *pmax16, uint16_t *pmin16)
static void compress_alpha(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
uint8_t pixel
Definition: tiny_ssim.c:42
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:105
common internal and external API header
#define lerp13(a, b)
static double c[64]
static const uint8_t match6[256][2]
Definition: texturedspenc.c:96
#define AV_WL16(p, v)
Definition: intreadwrite.h:412
static const uint8_t expand5[32]
Definition: texturedspenc.c:35
static const uint8_t expand6[64]
Definition: texturedspenc.c:41
#define FFSWAP(type, a, b)
Definition: common.h:99
#define stride
float min
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
int(* dxt5ys_block)(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
Definition: texturedsp.h:53
static void compress_color(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
#define AV_WL32(p, v)
Definition: intreadwrite.h:426
static int16_t block[64]
Definition: dct-test.c:112