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Side by Side Diff: cc/resources/texture_compressor_util.h

Issue 1096703002: Reland: Add ETC1 powered SSE encoder for tile texture compression (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Adding unit test for texture compression Created 5 years, 7 months ago
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1 // Copyright 2015 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef CC_RESOURCES_TEXTURE_COMPRESSOR_UTIL_H_
6 #define CC_RESOURCES_TEXTURE_COMPRESSOR_UTIL_H_
7
8 namespace cc {
9 namespace texture_compress {
christiank 2015/04/29 12:25:46 We don't use the texture_compress namespace any lo
10
11 #include "base/compiler_specific.h"
12 #include "base/logging.h"
13
14 template <typename T>
15 inline T clamp(T val, T min, T max) {
16 return val < min ? min : (val > max ? max : val);
17 }
18
19 inline uint8_t round_to_5_bits(float val) {
20 return clamp<uint8_t>(val * 31.0f / 255.0f + 0.5f, 0, 31);
21 }
22
23 inline uint8_t round_to_4_bits(float val) {
24 return clamp<uint8_t>(val * 15.0f / 255.0f + 0.5f, 0, 15);
25 }
26
27 union Color {
28 struct BgraColorType {
29 uint8_t b;
30 uint8_t g;
31 uint8_t r;
32 uint8_t a;
33 } channels;
34 uint8_t components[4];
35 uint32_t bits;
36 };
37
38 /*
39 * Codeword tables.
40 * See: Table 3.17.2
41 */
42 ALIGNAS(16) static const int16_t g_codeword_tables[8][4] = {
43 {-8, -2, 2, 8},
44 {-17, -5, 5, 17},
45 {-29, -9, 9, 29},
46 {-42, -13, 13, 42},
47 {-60, -18, 18, 60},
48 {-80, -24, 24, 80},
49 {-106, -33, 33, 106},
50 {-183, -47, 47, 183}};
51
52 /*
53 * Maps modifier indices to pixel index values.
54 * See: Table 3.17.3
55 */
56 static const uint8_t g_mod_to_pix[4] = {3, 2, 0, 1};
57
58 /*
59 * The ETC1 specification index texels as follows:
60 *
61 * [a][e][i][m] [ 0][ 4][ 8][12]
62 * [b][f][j][n] <-> [ 1][ 5][ 9][13]
63 * [c][g][k][o] [ 2][ 6][10][14]
64 * [d][h][l][p] [ 3][ 7][11][15]
65 *
66 * [ 0][ 1][ 2][ 3] [ 0][ 4][ 4][ 5]
67 * [ 4][ 5][ 6][ 7] <-> [ 8][ 9][12][13]
68 * [ 8][ 9][10][11] [ 2][ 3][ 6][ 7]
69 * [12][13][14][15] [10][11][14][15]
70 *
71 * However, when extracting sub blocks from BGRA data the natural array
72 * indexing order ends up different:
73 *
74 * vertical0: [a][e][b][f] horizontal0: [a][e][i][m]
75 * [c][g][d][h] [b][f][j][n]
76 * vertical1: [i][m][j][n] horizontal1: [c][g][k][o]
77 * [k][o][l][p] [d][h][l][p]
78 *
79 * In order to translate from the natural array indices in a sub block to the
80 * indices (number) used by specification and hardware we use this table.
81 */
82 static const uint8_t g_idx_to_num[4][8] = {
83 {0, 4, 1, 5, 2, 6, 3, 7}, // Vertical block 0.
84 {8, 12, 9, 13, 10, 14, 11, 15}, // Vertical block 1.
85 {0, 4, 8, 12, 1, 5, 9, 13}, // Horizontal block 0.
86 {2, 6, 10, 14, 3, 7, 11, 15} // Horizontal block 1.
87 };
88
89 inline void WriteColors444(uint8_t* block,
90 const Color& color0,
91 const Color& color1) {
92 /* for BGRA textures */
93 block[0] = (color0.channels.r & 0xf0) | (color1.channels.r >> 4);
94 block[1] = (color0.channels.g & 0xf0) | (color1.channels.g >> 4);
95 block[2] = (color0.channels.b & 0xf0) | (color1.channels.b >> 4);
96 }
97
98 inline void WriteColors555(uint8_t* block,
99 const Color& color0,
100 const Color& color1) {
101 // Table for conversion to 3-bit two complement format.
102 static const uint8_t two_compl_trans_table[8] = {
103 4, // -4 (100b)
104 5, // -3 (101b)
105 6, // -2 (110b)
106 7, // -1 (111b)
107 0, // 0 (000b)
108 1, // 1 (001b)
109 2, // 2 (010b)
110 3, // 3 (011b)
111 };
112
113 int16_t delta_r =
114 static_cast<int16_t>(color1.channels.r >> 3) - (color0.channels.r >> 3);
115 int16_t delta_g =
116 static_cast<int16_t>(color1.channels.g >> 3) - (color0.channels.g >> 3);
117 int16_t delta_b =
118 static_cast<int16_t>(color1.channels.b >> 3) - (color0.channels.b >> 3);
119 DCHECK(delta_r >= -4 && delta_r <= 3);
120 DCHECK(delta_g >= -4 && delta_g <= 3);
121 DCHECK(delta_b >= -4 && delta_b <= 3);
122
123 /* For BGRA textures */
124 block[0] = (color0.channels.r & 0xf8) | two_compl_trans_table[delta_r + 4];
125 block[1] = (color0.channels.g & 0xf8) | two_compl_trans_table[delta_g + 4];
126 block[2] = (color0.channels.b & 0xf8) | two_compl_trans_table[delta_b + 4];
127 }
128
129 inline void WriteCodewordTable(uint8_t* block,
130 uint8_t sub_block_id,
131 uint8_t table) {
132 DCHECK_LT(sub_block_id, 2);
133 DCHECK_LT(table, 8);
134
135 uint8_t shift = (2 + (3 - sub_block_id * 3));
136 block[3] &= ~(0x07 << shift);
137 block[3] |= table << shift;
138 }
139
140 inline void WritePixelData(uint8_t* block, uint32_t pixel_data) {
141 block[4] |= pixel_data >> 24;
142 block[5] |= (pixel_data >> 16) & 0xff;
143 block[6] |= (pixel_data >> 8) & 0xff;
144 block[7] |= pixel_data & 0xff;
145 }
146
147 inline void WriteFlip(uint8_t* block, bool flip) {
148 block[3] &= ~0x01;
149 block[3] |= static_cast<uint8_t>(flip);
150 }
151
152 inline void WriteDiff(uint8_t* block, bool diff) {
153 block[3] &= ~0x02;
154 block[3] |= static_cast<uint8_t>(diff) << 1;
155 }
156
157 /**
158 * Compress and rounds BGR888 into BGR444. The resulting BGR444 color is
159 * expanded to BGR888 as it would be in hardware after decompression. The
160 * actual 444-bit data is available in the four most significant bits of each
161 * channel.
162 */
163 inline Color MakeColor444(const float* bgr) {
164 uint8_t b4 = round_to_4_bits(bgr[0]);
165 uint8_t g4 = round_to_4_bits(bgr[1]);
166 uint8_t r4 = round_to_4_bits(bgr[2]);
167 Color bgr444;
168 bgr444.channels.b = (b4 << 4) | b4;
169 bgr444.channels.g = (g4 << 4) | g4;
170 bgr444.channels.r = (r4 << 4) | r4;
171 bgr444.channels.a =
172 0x44; /* added to distinguish between expanded 555 and 444 colors */
173 return bgr444;
174 }
175
176 /**
177 * Compress and rounds BGR888 into BGR555. The resulting BGR555 color is
178 * expanded to BGR888 as it would be in hardware after decompression. The
179 * actual 555-bit data is available in the five most significant bits of each
180 * channel.
181 */
182 inline Color MakeColor555(const float* bgr) {
183 uint8_t b5 = round_to_5_bits(bgr[0]);
184 uint8_t g5 = round_to_5_bits(bgr[1]);
185 uint8_t r5 = round_to_5_bits(bgr[2]);
186 Color bgr555;
187 bgr555.channels.b = (b5 << 3) | (b5 >> 2);
188 bgr555.channels.g = (g5 << 3) | (g5 >> 2);
189 bgr555.channels.r = (r5 << 3) | (r5 >> 2);
190 bgr555.channels.a =
191 0x55; /* added to distinguish between expanded 555 and 444 colors */
192 return bgr555;
193 }
194
195 /**
196 * Constructs a color from a given base color and luminance value.
197 */
198 inline Color MakeColor(const Color& base, int16_t lum) {
199 int b = static_cast<int>(base.channels.b) + lum;
200 int g = static_cast<int>(base.channels.g) + lum;
201 int r = static_cast<int>(base.channels.r) + lum;
202 Color color;
203 color.channels.b = static_cast<uint8_t>(clamp(b, 0, 255));
204 color.channels.g = static_cast<uint8_t>(clamp(g, 0, 255));
205 color.channels.r = static_cast<uint8_t>(clamp(r, 0, 255));
206 return color;
207 }
208
209 /**
210 * Calculates the error metric for two colors. A small error signals that the
211 * colors are similar to each other, a large error the signals the opposite.
212 */
213 inline uint32_t GetColorError(const Color& u, const Color& v) {
214 #ifdef USE_PERCEIVED_ERROR_METRIC
215 float delta_b = static_cast<float>(u.channels.b) - v.channels.b;
216 float delta_g = static_cast<float>(u.channels.g) - v.channels.g;
217 float delta_r = static_cast<float>(u.channels.r) - v.channels.r;
218 return static_cast<uint32_t>(0.299f * delta_b * delta_b +
219 0.587f * delta_g * delta_g +
220 0.114f * delta_r * delta_r);
221 #else
222 int delta_b = static_cast<int>(u.channels.b) - v.channels.b;
223 int delta_g = static_cast<int>(u.channels.g) - v.channels.g;
224 int delta_r = static_cast<int>(u.channels.r) - v.channels.r;
225 return delta_b * delta_b + delta_g * delta_g + delta_r * delta_r;
226 #endif
227 }
228
229 } // namespace texture_compress
230 } // namespace cc
231
232 #endif // CC_RESOURCES_TEXTURE_COMPRESSOR_UTIL_H_
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