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Diffstat (limited to 'thirdparty/basis_universal/encoder/basisu_etc.cpp')
-rw-r--r--thirdparty/basis_universal/encoder/basisu_etc.cpp1593
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diff --git a/thirdparty/basis_universal/encoder/basisu_etc.cpp b/thirdparty/basis_universal/encoder/basisu_etc.cpp
new file mode 100644
index 0000000000..232e8965b0
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+++ b/thirdparty/basis_universal/encoder/basisu_etc.cpp
@@ -0,0 +1,1593 @@
+// basis_etc.cpp
+// Copyright (C) 2019-2021 Binomial LLC. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include "basisu_etc.h"
+
+#if BASISU_SUPPORT_SSE
+#define CPPSPMD_NAME(a) a##_sse41
+#include "basisu_kernels_declares.h"
+#endif
+
+#define BASISU_DEBUG_ETC_ENCODER 0
+#define BASISU_DEBUG_ETC_ENCODER_DEEPER 0
+
+namespace basisu
+{
+ const int8_t g_etc2_eac_tables[16][8] =
+ {
+ { -3, -6, -9, -15, 2, 5, 8, 14 }, { -3, -7, -10, -13, 2, 6, 9, 12 }, { -2, -5, -8, -13, 1, 4, 7, 12 }, { -2, -4, -6, -13, 1, 3, 5, 12 },
+ { -3, -6, -8, -12, 2, 5, 7, 11 }, { -3, -7, -9, -11, 2, 6, 8, 10 }, { -4, -7, -8, -11, 3, 6, 7, 10 }, { -3, -5, -8, -11, 2, 4, 7, 10 },
+ { -2, -6, -8, -10, 1, 5, 7, 9 }, { -2, -5, -8, -10, 1, 4, 7, 9 }, { -2, -4, -8, -10, 1, 3, 7, 9 }, { -2, -5, -7, -10, 1, 4, 6, 9 },
+ { -3, -4, -7, -10, 2, 3, 6, 9 }, { -1, -2, -3, -10, 0, 1, 2, 9 }, { -4, -6, -8, -9, 3, 5, 7, 8 }, { -3, -5, -7, -9, 2, 4, 6, 8 }
+ };
+
+ const int8_t g_etc2_eac_tables8[16][8] =
+ {
+ { -24, -48, -72, -120, 16, 40, 64, 112 }, { -24,-56,-80,-104,16,48,72,96 }, { -16,-40,-64,-104,8,32,56,96 }, { -16,-32,-48,-104,8,24,40,96 },
+ { -24,-48,-64,-96,16,40,56,88 }, { -24,-56,-72,-88,16,48,64,80 }, { -32,-56,-64,-88,24,48,56,80 }, { -24,-40,-64,-88,16,32,56,80 },
+ { -16,-48,-64,-80,8,40,56,72 }, { -16,-40,-64,-80,8,32,56,72 }, { -16,-32,-64,-80,8,24,56,72 }, { -16,-40,-56,-80,8,32,48,72 },
+ { -24,-32,-56,-80,16,24,48,72 }, { -8,-16,-24,-80,0,8,16,72 }, { -32,-48,-64,-72,24,40,56,64 }, { -24,-40,-56,-72,16,32,48,64 }
+ };
+
+ // Given an ETC1 diff/inten_table/selector, and an 8-bit desired color, this table encodes the best packed_color in the low byte, and the abs error in the high byte.
+ static uint16_t g_etc1_inverse_lookup[2 * 8 * 4][256]; // [ diff/inten_table/selector][desired_color ]
+
+ // g_color8_to_etc_block_config[color][table_index] = Supplies for each 8-bit color value a list of packed ETC1 diff/intensity table/selectors/packed_colors that map to that color.
+ // To pack: diff | (inten << 1) | (selector << 4) | (packed_c << 8)
+ static const uint16_t g_etc1_color8_to_etc_block_config_0_255[2][33] =
+ {
+ { 0x0000, 0x0010, 0x0002, 0x0012, 0x0004, 0x0014, 0x0006, 0x0016, 0x0008, 0x0018, 0x000A, 0x001A, 0x000C, 0x001C, 0x000E, 0x001E, 0x0001, 0x0011, 0x0003, 0x0013, 0x0005, 0x0015, 0x0007, 0x0017, 0x0009, 0x0019, 0x000B, 0x001B, 0x000D, 0x001D, 0x000F, 0x001F, 0xFFFF },
+ { 0x0F20, 0x0F30, 0x0E32, 0x0F22, 0x0E34, 0x0F24, 0x0D36, 0x0F26, 0x0C38, 0x0E28, 0x0B3A, 0x0E2A, 0x093C, 0x0E2C, 0x053E, 0x0D2E, 0x1E31, 0x1F21, 0x1D33, 0x1F23, 0x1C35, 0x1E25, 0x1A37, 0x1E27, 0x1839, 0x1D29, 0x163B, 0x1C2B, 0x133D, 0x1B2D, 0x093F, 0x1A2F, 0xFFFF },
+ };
+
+ // Really only [254][11].
+ static const uint16_t g_etc1_color8_to_etc_block_config_1_to_254[254][12] =
+ {
+ { 0x021C, 0x0D0D, 0xFFFF }, { 0x0020, 0x0021, 0x0A0B, 0x061F, 0xFFFF }, { 0x0113, 0x0217, 0xFFFF }, { 0x0116, 0x031E, 0x0B0E, 0x0405, 0xFFFF }, { 0x0022, 0x0204, 0x050A, 0x0023, 0xFFFF }, { 0x0111, 0x0319, 0x0809, 0x170F, 0xFFFF }, {
+ 0x0303, 0x0215, 0x0607, 0xFFFF }, { 0x0030, 0x0114, 0x0408, 0x0031, 0x0201, 0x051D, 0xFFFF }, { 0x0100, 0x0024, 0x0306, 0x0025, 0x041B, 0x0E0D, 0xFFFF }, { 0x021A, 0x0121, 0x0B0B, 0x071F, 0xFFFF }, { 0x0213, 0x0317, 0xFFFF }, { 0x0112,
+ 0x0505, 0xFFFF }, { 0x0026, 0x070C, 0x0123, 0x0027, 0xFFFF }, { 0x0211, 0x0909, 0xFFFF }, { 0x0110, 0x0315, 0x0707, 0x0419, 0x180F, 0xFFFF }, { 0x0218, 0x0131, 0x0301, 0x0403, 0x061D, 0xFFFF }, { 0x0032, 0x0202, 0x0033, 0x0125, 0x051B,
+ 0x0F0D, 0xFFFF }, { 0x0028, 0x031C, 0x0221, 0x0029, 0xFFFF }, { 0x0120, 0x0313, 0x0C0B, 0x081F, 0xFFFF }, { 0x0605, 0x0417, 0xFFFF }, { 0x0216, 0x041E, 0x0C0E, 0x0223, 0x0127, 0xFFFF }, { 0x0122, 0x0304, 0x060A, 0x0311, 0x0A09, 0xFFFF
+ }, { 0x0519, 0x190F, 0xFFFF }, { 0x002A, 0x0231, 0x0503, 0x0415, 0x0807, 0x002B, 0x071D, 0xFFFF }, { 0x0130, 0x0214, 0x0508, 0x0401, 0x0133, 0x0225, 0x061B, 0xFFFF }, { 0x0200, 0x0124, 0x0406, 0x0321, 0x0129, 0x100D, 0xFFFF }, { 0x031A,
+ 0x0D0B, 0x091F, 0xFFFF }, { 0x0413, 0x0705, 0x0517, 0xFFFF }, { 0x0212, 0x0034, 0x0323, 0x0035, 0x0227, 0xFFFF }, { 0x0126, 0x080C, 0x0B09, 0xFFFF }, { 0x0411, 0x0619, 0x1A0F, 0xFFFF }, { 0x0210, 0x0331, 0x0603, 0x0515, 0x0907, 0x012B,
+ 0xFFFF }, { 0x0318, 0x002C, 0x0501, 0x0233, 0x0325, 0x071B, 0x002D, 0x081D, 0xFFFF }, { 0x0132, 0x0302, 0x0229, 0x110D, 0xFFFF }, { 0x0128, 0x041C, 0x0421, 0x0E0B, 0x0A1F, 0xFFFF }, { 0x0220, 0x0513, 0x0617, 0xFFFF }, { 0x0135, 0x0805,
+ 0x0327, 0xFFFF }, { 0x0316, 0x051E, 0x0D0E, 0x0423, 0xFFFF }, { 0x0222, 0x0404, 0x070A, 0x0511, 0x0719, 0x0C09, 0x1B0F, 0xFFFF }, { 0x0703, 0x0615, 0x0A07, 0x022B, 0xFFFF }, { 0x012A, 0x0431, 0x0601, 0x0333, 0x012D, 0x091D, 0xFFFF }, {
+ 0x0230, 0x0314, 0x0036, 0x0608, 0x0425, 0x0037, 0x0329, 0x081B, 0x120D, 0xFFFF }, { 0x0300, 0x0224, 0x0506, 0x0521, 0x0F0B, 0x0B1F, 0xFFFF }, { 0x041A, 0x0613, 0x0717, 0xFFFF }, { 0x0235, 0x0905, 0xFFFF }, { 0x0312, 0x0134, 0x0523,
+ 0x0427, 0xFFFF }, { 0x0226, 0x090C, 0x002E, 0x0611, 0x0D09, 0x002F, 0xFFFF }, { 0x0715, 0x0B07, 0x0819, 0x032B, 0x1C0F, 0xFFFF }, { 0x0310, 0x0531, 0x0701, 0x0803, 0x022D, 0x0A1D, 0xFFFF }, { 0x0418, 0x012C, 0x0433, 0x0525, 0x0137, 0x091B,
+ 0x130D, 0xFFFF }, { 0x0232, 0x0402, 0x0621, 0x0429, 0xFFFF }, { 0x0228, 0x051C, 0x0713, 0x100B, 0x0C1F, 0xFFFF }, { 0x0320, 0x0335, 0x0A05, 0x0817, 0xFFFF }, { 0x0623, 0x0527, 0xFFFF }, { 0x0416, 0x061E, 0x0E0E, 0x0711, 0x0E09, 0x012F,
+ 0xFFFF }, { 0x0322, 0x0504, 0x080A, 0x0919, 0x1D0F, 0xFFFF }, { 0x0631, 0x0903, 0x0815, 0x0C07, 0x042B, 0x032D, 0x0B1D, 0xFFFF }, { 0x022A, 0x0801, 0x0533, 0x0625, 0x0237, 0x0A1B, 0xFFFF }, { 0x0330, 0x0414, 0x0136, 0x0708, 0x0721, 0x0529,
+ 0x140D, 0xFFFF }, { 0x0400, 0x0324, 0x0606, 0x0038, 0x0039, 0x110B, 0x0D1F, 0xFFFF }, { 0x051A, 0x0813, 0x0B05, 0x0917, 0xFFFF }, { 0x0723, 0x0435, 0x0627, 0xFFFF }, { 0x0412, 0x0234, 0x0F09, 0x022F, 0xFFFF }, { 0x0326, 0x0A0C, 0x012E,
+ 0x0811, 0x0A19, 0x1E0F, 0xFFFF }, { 0x0731, 0x0A03, 0x0915, 0x0D07, 0x052B, 0xFFFF }, { 0x0410, 0x0901, 0x0633, 0x0725, 0x0337, 0x0B1B, 0x042D, 0x0C1D, 0xFFFF }, { 0x0518, 0x022C, 0x0629, 0x150D, 0xFFFF }, { 0x0332, 0x0502, 0x0821, 0x0139,
+ 0x120B, 0x0E1F, 0xFFFF }, { 0x0328, 0x061C, 0x0913, 0x0A17, 0xFFFF }, { 0x0420, 0x0535, 0x0C05, 0x0727, 0xFFFF }, { 0x0823, 0x032F, 0xFFFF }, { 0x0516, 0x071E, 0x0F0E, 0x0911, 0x0B19, 0x1009, 0x1F0F, 0xFFFF }, { 0x0422, 0x0604, 0x090A,
+ 0x0B03, 0x0A15, 0x0E07, 0x062B, 0xFFFF }, { 0x0831, 0x0A01, 0x0733, 0x052D, 0x0D1D, 0xFFFF }, { 0x032A, 0x0825, 0x0437, 0x0729, 0x0C1B, 0x160D, 0xFFFF }, { 0x0430, 0x0514, 0x0236, 0x0808, 0x0921, 0x0239, 0x130B, 0x0F1F, 0xFFFF }, { 0x0500,
+ 0x0424, 0x0706, 0x0138, 0x0A13, 0x0B17, 0xFFFF }, { 0x061A, 0x0635, 0x0D05, 0xFFFF }, { 0x0923, 0x0827, 0xFFFF }, { 0x0512, 0x0334, 0x003A, 0x0A11, 0x1109, 0x003B, 0x042F, 0xFFFF }, { 0x0426, 0x0B0C, 0x022E, 0x0B15, 0x0F07, 0x0C19,
+ 0x072B, 0xFFFF }, { 0x0931, 0x0B01, 0x0C03, 0x062D, 0x0E1D, 0xFFFF }, { 0x0510, 0x0833, 0x0925, 0x0537, 0x0D1B, 0x170D, 0xFFFF }, { 0x0618, 0x032C, 0x0A21, 0x0339, 0x0829, 0xFFFF }, { 0x0432, 0x0602, 0x0B13, 0x140B, 0x101F, 0xFFFF }, {
+ 0x0428, 0x071C, 0x0735, 0x0E05, 0x0C17, 0xFFFF }, { 0x0520, 0x0A23, 0x0927, 0xFFFF }, { 0x0B11, 0x1209, 0x013B, 0x052F, 0xFFFF }, { 0x0616, 0x081E, 0x0D19, 0xFFFF }, { 0x0522, 0x0704, 0x0A0A, 0x0A31, 0x0D03, 0x0C15, 0x1007, 0x082B, 0x072D,
+ 0x0F1D, 0xFFFF }, { 0x0C01, 0x0933, 0x0A25, 0x0637, 0x0E1B, 0xFFFF }, { 0x042A, 0x0B21, 0x0929, 0x180D, 0xFFFF }, { 0x0530, 0x0614, 0x0336, 0x0908, 0x0439, 0x150B, 0x111F, 0xFFFF }, { 0x0600, 0x0524, 0x0806, 0x0238, 0x0C13, 0x0F05,
+ 0x0D17, 0xFFFF }, { 0x071A, 0x0B23, 0x0835, 0x0A27, 0xFFFF }, { 0x1309, 0x023B, 0x062F, 0xFFFF }, { 0x0612, 0x0434, 0x013A, 0x0C11, 0x0E19, 0xFFFF }, { 0x0526, 0x0C0C, 0x032E, 0x0B31, 0x0E03, 0x0D15, 0x1107, 0x092B, 0xFFFF }, { 0x0D01,
+ 0x0A33, 0x0B25, 0x0737, 0x0F1B, 0x082D, 0x101D, 0xFFFF }, { 0x0610, 0x0A29, 0x190D, 0xFFFF }, { 0x0718, 0x042C, 0x0C21, 0x0539, 0x160B, 0x121F, 0xFFFF }, { 0x0532, 0x0702, 0x0D13, 0x0E17, 0xFFFF }, { 0x0528, 0x081C, 0x0935, 0x1005, 0x0B27,
+ 0xFFFF }, { 0x0620, 0x0C23, 0x033B, 0x072F, 0xFFFF }, { 0x0D11, 0x0F19, 0x1409, 0xFFFF }, { 0x0716, 0x003C, 0x091E, 0x0F03, 0x0E15, 0x1207, 0x0A2B, 0x003D, 0xFFFF }, { 0x0622, 0x0804, 0x0B0A, 0x0C31, 0x0E01, 0x0B33, 0x092D, 0x111D,
+ 0xFFFF }, { 0x0C25, 0x0837, 0x0B29, 0x101B, 0x1A0D, 0xFFFF }, { 0x052A, 0x0D21, 0x0639, 0x170B, 0x131F, 0xFFFF }, { 0x0630, 0x0714, 0x0436, 0x0A08, 0x0E13, 0x0F17, 0xFFFF }, { 0x0700, 0x0624, 0x0906, 0x0338, 0x0A35, 0x1105, 0xFFFF }, {
+ 0x081A, 0x0D23, 0x0C27, 0xFFFF }, { 0x0E11, 0x1509, 0x043B, 0x082F, 0xFFFF }, { 0x0712, 0x0534, 0x023A, 0x0F15, 0x1307, 0x1019, 0x0B2B, 0x013D, 0xFFFF }, { 0x0626, 0x0D0C, 0x042E, 0x0D31, 0x0F01, 0x1003, 0x0A2D, 0x121D, 0xFFFF }, { 0x0C33,
+ 0x0D25, 0x0937, 0x111B, 0x1B0D, 0xFFFF }, { 0x0710, 0x0E21, 0x0739, 0x0C29, 0xFFFF }, { 0x0818, 0x052C, 0x0F13, 0x180B, 0x141F, 0xFFFF }, { 0x0632, 0x0802, 0x0B35, 0x1205, 0x1017, 0xFFFF }, { 0x0628, 0x091C, 0x0E23, 0x0D27, 0xFFFF }, {
+ 0x0720, 0x0F11, 0x1609, 0x053B, 0x092F, 0xFFFF }, { 0x1119, 0x023D, 0xFFFF }, { 0x0816, 0x013C, 0x0A1E, 0x0E31, 0x1103, 0x1015, 0x1407, 0x0C2B, 0x0B2D, 0x131D, 0xFFFF }, { 0x0722, 0x0904, 0x0C0A, 0x1001, 0x0D33, 0x0E25, 0x0A37, 0x121B,
+ 0xFFFF }, { 0x0F21, 0x0D29, 0x1C0D, 0xFFFF }, { 0x062A, 0x0839, 0x190B, 0x151F, 0xFFFF }, { 0x0730, 0x0814, 0x0536, 0x0B08, 0x1013, 0x1305, 0x1117, 0xFFFF }, { 0x0800, 0x0724, 0x0A06, 0x0438, 0x0F23, 0x0C35, 0x0E27, 0xFFFF }, { 0x091A,
+ 0x1709, 0x063B, 0x0A2F, 0xFFFF }, { 0x1011, 0x1219, 0x033D, 0xFFFF }, { 0x0812, 0x0634, 0x033A, 0x0F31, 0x1203, 0x1115, 0x1507, 0x0D2B, 0xFFFF }, { 0x0726, 0x0E0C, 0x052E, 0x1101, 0x0E33, 0x0F25, 0x0B37, 0x131B, 0x0C2D, 0x141D, 0xFFFF }, {
+ 0x0E29, 0x1D0D, 0xFFFF }, { 0x0810, 0x1021, 0x0939, 0x1A0B, 0x161F, 0xFFFF }, { 0x0918, 0x062C, 0x1113, 0x1217, 0xFFFF }, { 0x0732, 0x0902, 0x0D35, 0x1405, 0x0F27, 0xFFFF }, { 0x0728, 0x0A1C, 0x1023, 0x073B, 0x0B2F, 0xFFFF }, { 0x0820,
+ 0x1111, 0x1319, 0x1809, 0xFFFF }, { 0x1303, 0x1215, 0x1607, 0x0E2B, 0x043D, 0xFFFF }, { 0x0916, 0x023C, 0x0B1E, 0x1031, 0x1201, 0x0F33, 0x0D2D, 0x151D, 0xFFFF }, { 0x0822, 0x0A04, 0x0D0A, 0x1025, 0x0C37, 0x0F29, 0x141B, 0x1E0D, 0xFFFF }, {
+ 0x1121, 0x0A39, 0x1B0B, 0x171F, 0xFFFF }, { 0x072A, 0x1213, 0x1317, 0xFFFF }, { 0x0830, 0x0914, 0x0636, 0x0C08, 0x0E35, 0x1505, 0xFFFF }, { 0x0900, 0x0824, 0x0B06, 0x0538, 0x1123, 0x1027, 0xFFFF }, { 0x0A1A, 0x1211, 0x1909, 0x083B, 0x0C2F,
+ 0xFFFF }, { 0x1315, 0x1707, 0x1419, 0x0F2B, 0x053D, 0xFFFF }, { 0x0912, 0x0734, 0x043A, 0x1131, 0x1301, 0x1403, 0x0E2D, 0x161D, 0xFFFF }, { 0x0826, 0x0F0C, 0x062E, 0x1033, 0x1125, 0x0D37, 0x151B, 0x1F0D, 0xFFFF }, { 0x1221, 0x0B39, 0x1029,
+ 0xFFFF }, { 0x0910, 0x1313, 0x1C0B, 0x181F, 0xFFFF }, { 0x0A18, 0x072C, 0x0F35, 0x1605, 0x1417, 0xFFFF }, { 0x0832, 0x0A02, 0x1223, 0x1127, 0xFFFF }, { 0x0828, 0x0B1C, 0x1311, 0x1A09, 0x093B, 0x0D2F, 0xFFFF }, { 0x0920, 0x1519, 0x063D,
+ 0xFFFF }, { 0x1231, 0x1503, 0x1415, 0x1807, 0x102B, 0x0F2D, 0x171D, 0xFFFF }, { 0x0A16, 0x033C, 0x0C1E, 0x1401, 0x1133, 0x1225, 0x0E37, 0x161B, 0xFFFF }, { 0x0922, 0x0B04, 0x0E0A, 0x1321, 0x1129, 0xFFFF }, { 0x0C39, 0x1D0B, 0x191F, 0xFFFF
+ }, { 0x082A, 0x1413, 0x1705, 0x1517, 0xFFFF }, { 0x0930, 0x0A14, 0x0736, 0x0D08, 0x1323, 0x1035, 0x1227, 0xFFFF }, { 0x0A00, 0x0924, 0x0C06, 0x0638, 0x1B09, 0x0A3B, 0x0E2F, 0xFFFF }, { 0x0B1A, 0x1411, 0x1619, 0x073D, 0xFFFF }, { 0x1331,
+ 0x1603, 0x1515, 0x1907, 0x112B, 0xFFFF }, { 0x0A12, 0x0834, 0x053A, 0x1501, 0x1233, 0x1325, 0x0F37, 0x171B, 0x102D, 0x181D, 0xFFFF }, { 0x0926, 0x072E, 0x1229, 0xFFFF }, { 0x1421, 0x0D39, 0x1E0B, 0x1A1F, 0xFFFF }, { 0x0A10, 0x1513,
+ 0x1617, 0xFFFF }, { 0x0B18, 0x082C, 0x1135, 0x1805, 0x1327, 0xFFFF }, { 0x0932, 0x0B02, 0x1423, 0x0B3B, 0x0F2F, 0xFFFF }, { 0x0928, 0x0C1C, 0x1511, 0x1719, 0x1C09, 0xFFFF }, { 0x0A20, 0x1703, 0x1615, 0x1A07, 0x122B, 0x083D, 0xFFFF }, {
+ 0x1431, 0x1601, 0x1333, 0x112D, 0x191D, 0xFFFF }, { 0x0B16, 0x043C, 0x0D1E, 0x1425, 0x1037, 0x1329, 0x181B, 0xFFFF }, { 0x0A22, 0x0C04, 0x0F0A, 0x1521, 0x0E39, 0x1F0B, 0x1B1F, 0xFFFF }, { 0x1613, 0x1717, 0xFFFF }, { 0x092A, 0x1235, 0x1905,
+ 0xFFFF }, { 0x0A30, 0x0B14, 0x0836, 0x0E08, 0x1523, 0x1427, 0xFFFF }, { 0x0B00, 0x0A24, 0x0D06, 0x0738, 0x1611, 0x1D09, 0x0C3B, 0x102F, 0xFFFF }, { 0x0C1A, 0x1715, 0x1B07, 0x1819, 0x132B, 0x093D, 0xFFFF }, { 0x1531, 0x1701, 0x1803, 0x122D,
+ 0x1A1D, 0xFFFF }, { 0x0B12, 0x0934, 0x063A, 0x1433, 0x1525, 0x1137, 0x191B, 0xFFFF }, { 0x0A26, 0x003E, 0x082E, 0x1621, 0x0F39, 0x1429, 0x003F, 0xFFFF }, { 0x1713, 0x1C1F, 0xFFFF }, { 0x0B10, 0x1335, 0x1A05, 0x1817, 0xFFFF }, { 0x0C18,
+ 0x092C, 0x1623, 0x1527, 0xFFFF }, { 0x0A32, 0x0C02, 0x1711, 0x1E09, 0x0D3B, 0x112F, 0xFFFF }, { 0x0A28, 0x0D1C, 0x1919, 0x0A3D, 0xFFFF }, { 0x0B20, 0x1631, 0x1903, 0x1815, 0x1C07, 0x142B, 0x132D, 0x1B1D, 0xFFFF }, { 0x1801, 0x1533, 0x1625,
+ 0x1237, 0x1A1B, 0xFFFF }, { 0x0C16, 0x053C, 0x0E1E, 0x1721, 0x1529, 0x013F, 0xFFFF }, { 0x0B22, 0x0D04, 0x1039, 0x1D1F, 0xFFFF }, { 0x1813, 0x1B05, 0x1917, 0xFFFF }, { 0x0A2A, 0x1723, 0x1435, 0x1627, 0xFFFF }, { 0x0B30, 0x0C14, 0x0936,
+ 0x0F08, 0x1F09, 0x0E3B, 0x122F, 0xFFFF }, { 0x0C00, 0x0B24, 0x0E06, 0x0838, 0x1811, 0x1A19, 0x0B3D, 0xFFFF }, { 0x0D1A, 0x1731, 0x1A03, 0x1915, 0x1D07, 0x152B, 0xFFFF }, { 0x1901, 0x1633, 0x1725, 0x1337, 0x1B1B, 0x142D, 0x1C1D, 0xFFFF }, {
+ 0x0C12, 0x0A34, 0x073A, 0x1629, 0x023F, 0xFFFF }, { 0x0B26, 0x013E, 0x092E, 0x1821, 0x1139, 0x1E1F, 0xFFFF }, { 0x1913, 0x1A17, 0xFFFF }, { 0x0C10, 0x1535, 0x1C05, 0x1727, 0xFFFF }, { 0x0D18, 0x0A2C, 0x1823, 0x0F3B, 0x132F, 0xFFFF }, {
+ 0x0B32, 0x0D02, 0x1911, 0x1B19, 0xFFFF }, { 0x0B28, 0x0E1C, 0x1B03, 0x1A15, 0x1E07, 0x162B, 0x0C3D, 0xFFFF }, { 0x0C20, 0x1831, 0x1A01, 0x1733, 0x152D, 0x1D1D, 0xFFFF }, { 0x1825, 0x1437, 0x1729, 0x1C1B, 0x033F, 0xFFFF }, { 0x0D16, 0x063C,
+ 0x0F1E, 0x1921, 0x1239, 0x1F1F, 0xFFFF }, { 0x0C22, 0x0E04, 0x1A13, 0x1B17, 0xFFFF }, { 0x1635, 0x1D05, 0xFFFF }, { 0x0B2A, 0x1923, 0x1827, 0xFFFF }, { 0x0C30, 0x0D14, 0x0A36, 0x1A11, 0x103B, 0x142F, 0xFFFF }, { 0x0D00, 0x0C24, 0x0F06,
+ 0x0938, 0x1B15, 0x1F07, 0x1C19, 0x172B, 0x0D3D, 0xFFFF }, { 0x0E1A, 0x1931, 0x1B01, 0x1C03, 0x162D, 0x1E1D, 0xFFFF }, { 0x1833, 0x1925, 0x1537, 0x1D1B, 0xFFFF }, { 0x0D12, 0x0B34, 0x083A, 0x1A21, 0x1339, 0x1829, 0x043F, 0xFFFF }, { 0x0C26,
+ 0x023E, 0x0A2E, 0x1B13, 0xFFFF }, { 0x1735, 0x1E05, 0x1C17, 0xFFFF }, { 0x0D10, 0x1A23, 0x1927, 0xFFFF }, { 0x0E18, 0x0B2C, 0x1B11, 0x113B, 0x152F, 0xFFFF }, { 0x0C32, 0x0E02, 0x1D19, 0x0E3D, 0xFFFF }, { 0x0C28, 0x0F1C, 0x1A31, 0x1D03,
+ 0x1C15, 0x182B, 0x172D, 0x1F1D, 0xFFFF }, { 0x0D20, 0x1C01, 0x1933, 0x1A25, 0x1637, 0x1E1B, 0xFFFF }, { 0x1B21, 0x1929, 0x053F, 0xFFFF }, { 0x0E16, 0x073C, 0x1439, 0xFFFF }, { 0x0D22, 0x0F04, 0x1C13, 0x1F05, 0x1D17, 0xFFFF }, { 0x1B23,
+ 0x1835, 0x1A27, 0xFFFF }, { 0x0C2A, 0x123B, 0x162F, 0xFFFF }, { 0x0D30, 0x0E14, 0x0B36, 0x1C11, 0x1E19, 0x0F3D, 0xFFFF }, { 0x0E00, 0x0D24, 0x0A38, 0x1B31, 0x1E03, 0x1D15, 0x192B, 0xFFFF }, { 0x0F1A, 0x1D01, 0x1A33, 0x1B25, 0x1737, 0x1F1B,
+ 0x182D, 0xFFFF }, { 0x1A29, 0x063F, 0xFFFF }, { 0x0E12, 0x0C34, 0x093A, 0x1C21, 0x1539, 0xFFFF }, { 0x0D26, 0x033E, 0x0B2E, 0x1D13, 0x1E17, 0xFFFF }, { 0x1935, 0x1B27, 0xFFFF }, { 0x0E10, 0x1C23, 0x133B, 0x172F, 0xFFFF }, { 0x0F18,
+ 0x0C2C, 0x1D11, 0x1F19, 0xFFFF }, { 0x0D32, 0x0F02, 0x1F03, 0x1E15, 0x1A2B, 0x103D, 0xFFFF }, { 0x0D28, 0x1C31, 0x1E01, 0x1B33, 0x192D, 0xFFFF }, { 0x0E20, 0x1C25, 0x1837, 0x1B29, 0x073F, 0xFFFF }, { 0x1D21, 0x1639, 0xFFFF }, { 0x0F16,
+ 0x083C, 0x1E13, 0x1F17, 0xFFFF }, { 0x0E22, 0x1A35, 0xFFFF }, { 0x1D23, 0x1C27, 0xFFFF }, { 0x0D2A, 0x1E11, 0x143B, 0x182F, 0xFFFF }, { 0x0E30, 0x0F14, 0x0C36, 0x1F15, 0x1B2B, 0x113D, 0xFFFF }, { 0x0F00, 0x0E24, 0x0B38, 0x1D31, 0x1F01,
+ 0x1A2D, 0xFFFF }, { 0x1C33, 0x1D25, 0x1937, 0xFFFF }, { 0x1E21, 0x1739, 0x1C29, 0x083F, 0xFFFF }, { 0x0F12, 0x0D34, 0x0A3A, 0x1F13, 0xFFFF }, { 0x0E26, 0x043E, 0x0C2E, 0x1B35, 0xFFFF }, { 0x1E23, 0x1D27, 0xFFFF }, { 0x0F10, 0x1F11, 0x153B, 0x192F, 0xFFFF }, { 0x0D2C, 0x123D, 0xFFFF },
+ };
+
+ static uint32_t etc1_decode_value(uint32_t diff, uint32_t inten, uint32_t selector, uint32_t packed_c)
+ {
+ const uint32_t limit = diff ? 32 : 16;
+ BASISU_NOTE_UNUSED(limit);
+ assert((diff < 2) && (inten < 8) && (selector < 4) && (packed_c < limit));
+ int c;
+ if (diff)
+ c = (packed_c >> 2) | (packed_c << 3);
+ else
+ c = packed_c | (packed_c << 4);
+ c += g_etc1_inten_tables[inten][selector];
+ c = clamp<int>(c, 0, 255);
+ return c;
+ }
+
+ void pack_etc1_solid_color_init()
+ {
+ for (uint32_t diff = 0; diff < 2; diff++)
+ {
+ const uint32_t limit = diff ? 32 : 16;
+
+ for (uint32_t inten = 0; inten < 8; inten++)
+ {
+ for (uint32_t selector = 0; selector < 4; selector++)
+ {
+ const uint32_t inverse_table_index = diff + (inten << 1) + (selector << 4);
+ for (uint32_t color = 0; color < 256; color++)
+ {
+ uint32_t best_error = UINT32_MAX, best_packed_c = 0;
+ for (uint32_t packed_c = 0; packed_c < limit; packed_c++)
+ {
+ int v = etc1_decode_value(diff, inten, selector, packed_c);
+ uint32_t err = (uint32_t)labs(v - static_cast<int>(color));
+ if (err < best_error)
+ {
+ best_error = err;
+ best_packed_c = packed_c;
+ if (!best_error)
+ break;
+ }
+ }
+ assert(best_error <= 255);
+ g_etc1_inverse_lookup[inverse_table_index][color] = static_cast<uint16_t>(best_packed_c | (best_error << 8));
+ }
+ }
+ }
+ }
+ }
+
+ // Packs solid color blocks efficiently using a set of small precomputed tables.
+ // For random 888 inputs, MSE results are better than Erricson's ETC1 packer in "slow" mode ~9.5% of the time, is slightly worse only ~.01% of the time, and is equal the rest of the time.
+ uint64_t pack_etc1_block_solid_color(etc_block& block, const uint8_t* pColor)
+ {
+ assert(g_etc1_inverse_lookup[0][255]);
+
+ static uint32_t s_next_comp[4] = { 1, 2, 0, 1 };
+
+ uint32_t best_error = UINT32_MAX, best_i = 0;
+ int best_x = 0, best_packed_c1 = 0, best_packed_c2 = 0;
+
+ // For each possible 8-bit value, there is a precomputed list of diff/inten/selector configurations that allow that 8-bit value to be encoded with no error.
+ for (uint32_t i = 0; i < 3; i++)
+ {
+ const uint32_t c1 = pColor[s_next_comp[i]], c2 = pColor[s_next_comp[i + 1]];
+
+ const int delta_range = 1;
+ for (int delta = -delta_range; delta <= delta_range; delta++)
+ {
+ const int c_plus_delta = clamp<int>(pColor[i] + delta, 0, 255);
+
+ const uint16_t* pTable;
+ if (!c_plus_delta)
+ pTable = g_etc1_color8_to_etc_block_config_0_255[0];
+ else if (c_plus_delta == 255)
+ pTable = g_etc1_color8_to_etc_block_config_0_255[1];
+ else
+ pTable = g_etc1_color8_to_etc_block_config_1_to_254[c_plus_delta - 1];
+
+ do
+ {
+ const uint32_t x = *pTable++;
+
+#ifdef _DEBUG
+ const uint32_t diff = x & 1;
+ const uint32_t inten = (x >> 1) & 7;
+ const uint32_t selector = (x >> 4) & 3;
+ const uint32_t p0 = (x >> 8) & 255;
+ assert(etc1_decode_value(diff, inten, selector, p0) == (uint32_t)c_plus_delta);
+#endif
+
+ const uint16_t* pInverse_table = g_etc1_inverse_lookup[x & 0xFF];
+ uint16_t p1 = pInverse_table[c1];
+ uint16_t p2 = pInverse_table[c2];
+ const uint32_t trial_error = square(c_plus_delta - pColor[i]) + square(p1 >> 8) + square(p2 >> 8);
+ if (trial_error < best_error)
+ {
+ best_error = trial_error;
+ best_x = x;
+ best_packed_c1 = p1 & 0xFF;
+ best_packed_c2 = p2 & 0xFF;
+ best_i = i;
+ if (!best_error)
+ goto found_perfect_match;
+ }
+ } while (*pTable != 0xFFFF);
+ }
+ }
+ found_perfect_match:
+
+ const uint32_t diff = best_x & 1;
+ const uint32_t inten = (best_x >> 1) & 7;
+
+ block.m_bytes[3] = static_cast<uint8_t>(((inten | (inten << 3)) << 2) | (diff << 1));
+
+ const uint32_t etc1_selector = g_selector_index_to_etc1[(best_x >> 4) & 3];
+ *reinterpret_cast<uint16_t*>(&block.m_bytes[4]) = (etc1_selector & 2) ? 0xFFFF : 0;
+ *reinterpret_cast<uint16_t*>(&block.m_bytes[6]) = (etc1_selector & 1) ? 0xFFFF : 0;
+
+ const uint32_t best_packed_c0 = (best_x >> 8) & 255;
+ if (diff)
+ {
+ block.m_bytes[best_i] = static_cast<uint8_t>(best_packed_c0 << 3);
+ block.m_bytes[s_next_comp[best_i]] = static_cast<uint8_t>(best_packed_c1 << 3);
+ block.m_bytes[s_next_comp[best_i + 1]] = static_cast<uint8_t>(best_packed_c2 << 3);
+ }
+ else
+ {
+ block.m_bytes[best_i] = static_cast<uint8_t>(best_packed_c0 | (best_packed_c0 << 4));
+ block.m_bytes[s_next_comp[best_i]] = static_cast<uint8_t>(best_packed_c1 | (best_packed_c1 << 4));
+ block.m_bytes[s_next_comp[best_i + 1]] = static_cast<uint8_t>(best_packed_c2 | (best_packed_c2 << 4));
+ }
+
+ return best_error;
+ }
+
+ const uint32_t BASISU_ETC1_CLUSTER_FIT_ORDER_TABLE_SIZE = 165;
+
+ static const struct { uint8_t m_v[4]; } g_cluster_fit_order_tab[BASISU_ETC1_CLUSTER_FIT_ORDER_TABLE_SIZE] =
+ {
+ { { 0, 0, 0, 8 } },{ { 0, 5, 2, 1 } },{ { 0, 6, 1, 1 } },{ { 0, 7, 0, 1 } },{ { 0, 7, 1, 0 } },
+ { { 0, 0, 8, 0 } },{ { 0, 0, 3, 5 } },{ { 0, 1, 7, 0 } },{ { 0, 0, 4, 4 } },{ { 0, 0, 2, 6 } },
+ { { 0, 0, 7, 1 } },{ { 0, 0, 1, 7 } },{ { 0, 0, 5, 3 } },{ { 1, 6, 0, 1 } },{ { 0, 0, 6, 2 } },
+ { { 0, 2, 6, 0 } },{ { 2, 4, 2, 0 } },{ { 0, 3, 5, 0 } },{ { 3, 3, 1, 1 } },{ { 4, 2, 0, 2 } },
+ { { 1, 5, 2, 0 } },{ { 0, 5, 3, 0 } },{ { 0, 6, 2, 0 } },{ { 2, 4, 1, 1 } },{ { 5, 1, 0, 2 } },
+ { { 6, 1, 1, 0 } },{ { 3, 3, 0, 2 } },{ { 6, 0, 0, 2 } },{ { 0, 8, 0, 0 } },{ { 6, 1, 0, 1 } },
+ { { 0, 1, 6, 1 } },{ { 1, 6, 1, 0 } },{ { 4, 1, 3, 0 } },{ { 0, 2, 5, 1 } },{ { 5, 0, 3, 0 } },
+ { { 5, 3, 0, 0 } },{ { 0, 1, 5, 2 } },{ { 0, 3, 4, 1 } },{ { 2, 5, 1, 0 } },{ { 1, 7, 0, 0 } },
+ { { 0, 1, 4, 3 } },{ { 6, 0, 2, 0 } },{ { 0, 4, 4, 0 } },{ { 2, 6, 0, 0 } },{ { 0, 2, 4, 2 } },
+ { { 0, 5, 1, 2 } },{ { 0, 6, 0, 2 } },{ { 3, 5, 0, 0 } },{ { 0, 4, 3, 1 } },{ { 3, 4, 1, 0 } },
+ { { 4, 3, 1, 0 } },{ { 1, 5, 0, 2 } },{ { 0, 3, 3, 2 } },{ { 1, 4, 1, 2 } },{ { 0, 4, 2, 2 } },
+ { { 2, 3, 3, 0 } },{ { 4, 4, 0, 0 } },{ { 1, 2, 4, 1 } },{ { 0, 5, 0, 3 } },{ { 0, 1, 3, 4 } },
+ { { 1, 5, 1, 1 } },{ { 1, 4, 2, 1 } },{ { 1, 3, 2, 2 } },{ { 5, 2, 1, 0 } },{ { 1, 3, 3, 1 } },
+ { { 0, 1, 2, 5 } },{ { 1, 1, 5, 1 } },{ { 0, 3, 2, 3 } },{ { 2, 5, 0, 1 } },{ { 3, 2, 2, 1 } },
+ { { 2, 3, 0, 3 } },{ { 1, 4, 3, 0 } },{ { 2, 2, 1, 3 } },{ { 6, 2, 0, 0 } },{ { 1, 0, 6, 1 } },
+ { { 3, 3, 2, 0 } },{ { 7, 1, 0, 0 } },{ { 3, 1, 4, 0 } },{ { 0, 2, 3, 3 } },{ { 0, 4, 1, 3 } },
+ { { 0, 4, 0, 4 } },{ { 0, 1, 0, 7 } },{ { 2, 0, 5, 1 } },{ { 2, 0, 4, 2 } },{ { 3, 0, 2, 3 } },
+ { { 2, 2, 4, 0 } },{ { 2, 2, 3, 1 } },{ { 4, 0, 3, 1 } },{ { 3, 2, 3, 0 } },{ { 2, 3, 2, 1 } },
+ { { 1, 3, 4, 0 } },{ { 7, 0, 1, 0 } },{ { 3, 0, 4, 1 } },{ { 1, 0, 5, 2 } },{ { 8, 0, 0, 0 } },
+ { { 3, 0, 1, 4 } },{ { 4, 1, 1, 2 } },{ { 4, 0, 2, 2 } },{ { 1, 2, 5, 0 } },{ { 4, 2, 1, 1 } },
+ { { 3, 4, 0, 1 } },{ { 2, 0, 3, 3 } },{ { 5, 0, 1, 2 } },{ { 5, 0, 0, 3 } },{ { 2, 4, 0, 2 } },
+ { { 2, 1, 4, 1 } },{ { 4, 0, 1, 3 } },{ { 2, 1, 5, 0 } },{ { 4, 2, 2, 0 } },{ { 4, 0, 4, 0 } },
+ { { 1, 0, 4, 3 } },{ { 1, 4, 0, 3 } },{ { 3, 0, 3, 2 } },{ { 4, 3, 0, 1 } },{ { 0, 1, 1, 6 } },
+ { { 1, 3, 1, 3 } },{ { 0, 2, 2, 4 } },{ { 2, 0, 2, 4 } },{ { 5, 1, 1, 1 } },{ { 3, 0, 5, 0 } },
+ { { 2, 3, 1, 2 } },{ { 3, 0, 0, 5 } },{ { 0, 3, 1, 4 } },{ { 5, 0, 2, 1 } },{ { 2, 1, 3, 2 } },
+ { { 2, 0, 6, 0 } },{ { 3, 1, 3, 1 } },{ { 5, 1, 2, 0 } },{ { 1, 0, 3, 4 } },{ { 1, 1, 6, 0 } },
+ { { 4, 0, 0, 4 } },{ { 2, 0, 1, 5 } },{ { 0, 3, 0, 5 } },{ { 1, 3, 0, 4 } },{ { 4, 1, 2, 1 } },
+ { { 1, 2, 3, 2 } },{ { 3, 1, 0, 4 } },{ { 5, 2, 0, 1 } },{ { 1, 2, 2, 3 } },{ { 3, 2, 1, 2 } },
+ { { 2, 2, 2, 2 } },{ { 6, 0, 1, 1 } },{ { 1, 2, 1, 4 } },{ { 1, 1, 4, 2 } },{ { 3, 2, 0, 3 } },
+ { { 1, 2, 0, 5 } },{ { 1, 0, 7, 0 } },{ { 3, 1, 2, 2 } },{ { 1, 0, 2, 5 } },{ { 2, 0, 0, 6 } },
+ { { 2, 1, 1, 4 } },{ { 2, 2, 0, 4 } },{ { 1, 1, 3, 3 } },{ { 7, 0, 0, 1 } },{ { 1, 0, 0, 7 } },
+ { { 2, 1, 2, 3 } },{ { 4, 1, 0, 3 } },{ { 3, 1, 1, 3 } },{ { 1, 1, 2, 4 } },{ { 2, 1, 0, 5 } },
+ { { 1, 0, 1, 6 } },{ { 0, 2, 1, 5 } },{ { 0, 2, 0, 6 } },{ { 1, 1, 1, 5 } },{ { 1, 1, 0, 6 } }
+ };
+
+ const int g_etc1_inten_tables[cETC1IntenModifierValues][cETC1SelectorValues] =
+ {
+ { -8, -2, 2, 8 }, { -17, -5, 5, 17 }, { -29, -9, 9, 29 }, { -42, -13, 13, 42 },
+ { -60, -18, 18, 60 }, { -80, -24, 24, 80 }, { -106, -33, 33, 106 }, { -183, -47, 47, 183 }
+ };
+
+ const uint8_t g_etc1_to_selector_index[cETC1SelectorValues] = { 2, 3, 1, 0 };
+ const uint8_t g_selector_index_to_etc1[cETC1SelectorValues] = { 3, 2, 0, 1 };
+
+ // [flip][subblock][pixel_index]
+ const etc_coord2 g_etc1_pixel_coords[2][2][8] =
+ {
+ {
+ {
+ { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 },
+ { 1, 0 }, { 1, 1 }, { 1, 2 }, { 1, 3 }
+ },
+ {
+ { 2, 0 }, { 2, 1 }, { 2, 2 }, { 2, 3 },
+ { 3, 0 }, { 3, 1 }, { 3, 2 }, { 3, 3 }
+ }
+ },
+ {
+ {
+ { 0, 0 }, { 1, 0 }, { 2, 0 }, { 3, 0 },
+ { 0, 1 }, { 1, 1 }, { 2, 1 }, { 3, 1 }
+ },
+ {
+ { 0, 2 }, { 1, 2 }, { 2, 2 }, { 3, 2 },
+ { 0, 3 }, { 1, 3 }, { 2, 3 }, { 3, 3 }
+ },
+ }
+ };
+
+ // [flip][subblock][pixel_index]
+ const uint32_t g_etc1_pixel_indices[2][2][8] =
+ {
+ {
+ {
+ 0 + 4 * 0, 0 + 4 * 1, 0 + 4 * 2, 0 + 4 * 3,
+ 1 + 4 * 0, 1 + 4 * 1, 1 + 4 * 2, 1 + 4 * 3
+ },
+ {
+ 2 + 4 * 0, 2 + 4 * 1, 2 + 4 * 2, 2 + 4 * 3,
+ 3 + 4 * 0, 3 + 4 * 1, 3 + 4 * 2, 3 + 4 * 3
+ }
+ },
+ {
+ {
+ 0 + 4 * 0, 1 + 4 * 0, 2 + 4 * 0, 3 + 4 * 0,
+ 0 + 4 * 1, 1 + 4 * 1, 2 + 4 * 1, 3 + 4 * 1
+ },
+ {
+ 0 + 4 * 2, 1 + 4 * 2, 2 + 4 * 2, 3 + 4 * 2,
+ 0 + 4 * 3, 1 + 4 * 3, 2 + 4 * 3, 3 + 4 * 3
+ },
+ }
+ };
+
+ uint16_t etc_block::pack_color5(const color_rgba& color, bool scaled, uint32_t bias)
+ {
+ return pack_color5(color.r, color.g, color.b, scaled, bias);
+ }
+
+ uint16_t etc_block::pack_color5(uint32_t r, uint32_t g, uint32_t b, bool scaled, uint32_t bias)
+ {
+ if (scaled)
+ {
+ r = (r * 31U + bias) / 255U;
+ g = (g * 31U + bias) / 255U;
+ b = (b * 31U + bias) / 255U;
+ }
+
+ r = minimum(r, 31U);
+ g = minimum(g, 31U);
+ b = minimum(b, 31U);
+
+ return static_cast<uint16_t>(b | (g << 5U) | (r << 10U));
+ }
+
+ color_rgba etc_block::unpack_color5(uint16_t packed_color5, bool scaled, uint32_t alpha)
+ {
+ uint32_t b = packed_color5 & 31U;
+ uint32_t g = (packed_color5 >> 5U) & 31U;
+ uint32_t r = (packed_color5 >> 10U) & 31U;
+
+ if (scaled)
+ {
+ b = (b << 3U) | (b >> 2U);
+ g = (g << 3U) | (g >> 2U);
+ r = (r << 3U) | (r >> 2U);
+ }
+
+ return color_rgba(cNoClamp, r, g, b, minimum(alpha, 255U));
+ }
+
+ void etc_block::unpack_color5(color_rgba& result, uint16_t packed_color5, bool scaled)
+ {
+ result = unpack_color5(packed_color5, scaled, 255);
+ }
+
+ void etc_block::unpack_color5(uint32_t& r, uint32_t& g, uint32_t& b, uint16_t packed_color5, bool scaled)
+ {
+ color_rgba c(unpack_color5(packed_color5, scaled, 0));
+ r = c.r;
+ g = c.g;
+ b = c.b;
+ }
+
+ bool etc_block::unpack_color5(color_rgba& result, uint16_t packed_color5, uint16_t packed_delta3, bool scaled, uint32_t alpha)
+ {
+ color_rgba_i16 dc(unpack_delta3(packed_delta3));
+
+ int b = (packed_color5 & 31U) + dc.b;
+ int g = ((packed_color5 >> 5U) & 31U) + dc.g;
+ int r = ((packed_color5 >> 10U) & 31U) + dc.r;
+
+ bool success = true;
+ if (static_cast<uint32_t>(r | g | b) > 31U)
+ {
+ success = false;
+ r = clamp<int>(r, 0, 31);
+ g = clamp<int>(g, 0, 31);
+ b = clamp<int>(b, 0, 31);
+ }
+
+ if (scaled)
+ {
+ b = (b << 3U) | (b >> 2U);
+ g = (g << 3U) | (g >> 2U);
+ r = (r << 3U) | (r >> 2U);
+ }
+
+ result.set_noclamp_rgba(r, g, b, minimum(alpha, 255U));
+ return success;
+ }
+
+ bool etc_block::unpack_color5(uint32_t& r, uint32_t& g, uint32_t& b, uint16_t packed_color5, uint16_t packed_delta3, bool scaled, uint32_t alpha)
+ {
+ color_rgba result;
+ const bool success = unpack_color5(result, packed_color5, packed_delta3, scaled, alpha);
+ r = result.r;
+ g = result.g;
+ b = result.b;
+ return success;
+ }
+
+ uint16_t etc_block::pack_delta3(const color_rgba_i16& color)
+ {
+ return pack_delta3(color.r, color.g, color.b);
+ }
+
+ uint16_t etc_block::pack_delta3(int r, int g, int b)
+ {
+ assert((r >= cETC1ColorDeltaMin) && (r <= cETC1ColorDeltaMax));
+ assert((g >= cETC1ColorDeltaMin) && (g <= cETC1ColorDeltaMax));
+ assert((b >= cETC1ColorDeltaMin) && (b <= cETC1ColorDeltaMax));
+ if (r < 0) r += 8;
+ if (g < 0) g += 8;
+ if (b < 0) b += 8;
+ return static_cast<uint16_t>(b | (g << 3) | (r << 6));
+ }
+
+ color_rgba_i16 etc_block::unpack_delta3(uint16_t packed_delta3)
+ {
+ int r = (packed_delta3 >> 6) & 7;
+ int g = (packed_delta3 >> 3) & 7;
+ int b = packed_delta3 & 7;
+ if (r >= 4) r -= 8;
+ if (g >= 4) g -= 8;
+ if (b >= 4) b -= 8;
+ return color_rgba_i16(r, g, b, 255);
+ }
+
+ void etc_block::unpack_delta3(int& r, int& g, int& b, uint16_t packed_delta3)
+ {
+ r = (packed_delta3 >> 6) & 7;
+ g = (packed_delta3 >> 3) & 7;
+ b = packed_delta3 & 7;
+ if (r >= 4) r -= 8;
+ if (g >= 4) g -= 8;
+ if (b >= 4) b -= 8;
+ }
+
+ uint16_t etc_block::pack_color4(const color_rgba& color, bool scaled, uint32_t bias)
+ {
+ return pack_color4(color.r, color.g, color.b, scaled, bias);
+ }
+
+ uint16_t etc_block::pack_color4(uint32_t r, uint32_t g, uint32_t b, bool scaled, uint32_t bias)
+ {
+ if (scaled)
+ {
+ r = (r * 15U + bias) / 255U;
+ g = (g * 15U + bias) / 255U;
+ b = (b * 15U + bias) / 255U;
+ }
+
+ r = minimum(r, 15U);
+ g = minimum(g, 15U);
+ b = minimum(b, 15U);
+
+ return static_cast<uint16_t>(b | (g << 4U) | (r << 8U));
+ }
+
+ color_rgba etc_block::unpack_color4(uint16_t packed_color4, bool scaled, uint32_t alpha)
+ {
+ uint32_t b = packed_color4 & 15U;
+ uint32_t g = (packed_color4 >> 4U) & 15U;
+ uint32_t r = (packed_color4 >> 8U) & 15U;
+
+ if (scaled)
+ {
+ b = (b << 4U) | b;
+ g = (g << 4U) | g;
+ r = (r << 4U) | r;
+ }
+
+ return color_rgba(cNoClamp, r, g, b, minimum(alpha, 255U));
+ }
+
+ void etc_block::unpack_color4(uint32_t& r, uint32_t& g, uint32_t& b, uint16_t packed_color4, bool scaled)
+ {
+ color_rgba c(unpack_color4(packed_color4, scaled, 0));
+ r = c.r;
+ g = c.g;
+ b = c.b;
+ }
+
+ void etc_block::get_diff_subblock_colors(color_rgba* pDst, uint16_t packed_color5, uint32_t table_idx)
+ {
+ assert(table_idx < cETC1IntenModifierValues);
+ const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
+
+ uint32_t r, g, b;
+ unpack_color5(r, g, b, packed_color5, true);
+
+ const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
+
+ const int y0 = pInten_modifer_table[0];
+ pDst[0].set(ir + y0, ig + y0, ib + y0, 255);
+
+ const int y1 = pInten_modifer_table[1];
+ pDst[1].set(ir + y1, ig + y1, ib + y1, 255);
+
+ const int y2 = pInten_modifer_table[2];
+ pDst[2].set(ir + y2, ig + y2, ib + y2, 255);
+
+ const int y3 = pInten_modifer_table[3];
+ pDst[3].set(ir + y3, ig + y3, ib + y3, 255);
+ }
+
+ bool etc_block::get_diff_subblock_colors(color_rgba* pDst, uint16_t packed_color5, uint16_t packed_delta3, uint32_t table_idx)
+ {
+ assert(table_idx < cETC1IntenModifierValues);
+ const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
+
+ uint32_t r, g, b;
+ bool success = unpack_color5(r, g, b, packed_color5, packed_delta3, true);
+
+ const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
+
+ const int y0 = pInten_modifer_table[0];
+ pDst[0].set(ir + y0, ig + y0, ib + y0, 255);
+
+ const int y1 = pInten_modifer_table[1];
+ pDst[1].set(ir + y1, ig + y1, ib + y1, 255);
+
+ const int y2 = pInten_modifer_table[2];
+ pDst[2].set(ir + y2, ig + y2, ib + y2, 255);
+
+ const int y3 = pInten_modifer_table[3];
+ pDst[3].set(ir + y3, ig + y3, ib + y3, 255);
+
+ return success;
+ }
+
+ void etc_block::get_abs_subblock_colors(color_rgba* pDst, uint16_t packed_color4, uint32_t table_idx)
+ {
+ assert(table_idx < cETC1IntenModifierValues);
+ const int *pInten_modifer_table = &g_etc1_inten_tables[table_idx][0];
+
+ uint32_t r, g, b;
+ unpack_color4(r, g, b, packed_color4, true);
+
+ const int ir = static_cast<int>(r), ig = static_cast<int>(g), ib = static_cast<int>(b);
+
+ const int y0 = pInten_modifer_table[0];
+ pDst[0].set(ir + y0, ig + y0, ib + y0, 255);
+
+ const int y1 = pInten_modifer_table[1];
+ pDst[1].set(ir + y1, ig + y1, ib + y1, 255);
+
+ const int y2 = pInten_modifer_table[2];
+ pDst[2].set(ir + y2, ig + y2, ib + y2, 255);
+
+ const int y3 = pInten_modifer_table[3];
+ pDst[3].set(ir + y3, ig + y3, ib + y3, 255);
+ }
+
+ bool unpack_etc1(const etc_block& block, color_rgba *pDst, bool preserve_alpha)
+ {
+ const bool diff_flag = block.get_diff_bit();
+ const bool flip_flag = block.get_flip_bit();
+ const uint32_t table_index0 = block.get_inten_table(0);
+ const uint32_t table_index1 = block.get_inten_table(1);
+
+ color_rgba subblock_colors0[4];
+ color_rgba subblock_colors1[4];
+
+ if (diff_flag)
+ {
+ const uint16_t base_color5 = block.get_base5_color();
+ const uint16_t delta_color3 = block.get_delta3_color();
+ etc_block::get_diff_subblock_colors(subblock_colors0, base_color5, table_index0);
+
+ if (!etc_block::get_diff_subblock_colors(subblock_colors1, base_color5, delta_color3, table_index1))
+ return false;
+ }
+ else
+ {
+ const uint16_t base_color4_0 = block.get_base4_color(0);
+ etc_block::get_abs_subblock_colors(subblock_colors0, base_color4_0, table_index0);
+
+ const uint16_t base_color4_1 = block.get_base4_color(1);
+ etc_block::get_abs_subblock_colors(subblock_colors1, base_color4_1, table_index1);
+ }
+
+ if (preserve_alpha)
+ {
+ if (flip_flag)
+ {
+ for (uint32_t y = 0; y < 2; y++)
+ {
+ pDst[0].set_rgb(subblock_colors0[block.get_selector(0, y)]);
+ pDst[1].set_rgb(subblock_colors0[block.get_selector(1, y)]);
+ pDst[2].set_rgb(subblock_colors0[block.get_selector(2, y)]);
+ pDst[3].set_rgb(subblock_colors0[block.get_selector(3, y)]);
+ pDst += 4;
+ }
+
+ for (uint32_t y = 2; y < 4; y++)
+ {
+ pDst[0].set_rgb(subblock_colors1[block.get_selector(0, y)]);
+ pDst[1].set_rgb(subblock_colors1[block.get_selector(1, y)]);
+ pDst[2].set_rgb(subblock_colors1[block.get_selector(2, y)]);
+ pDst[3].set_rgb(subblock_colors1[block.get_selector(3, y)]);
+ pDst += 4;
+ }
+ }
+ else
+ {
+ for (uint32_t y = 0; y < 4; y++)
+ {
+ pDst[0].set_rgb(subblock_colors0[block.get_selector(0, y)]);
+ pDst[1].set_rgb(subblock_colors0[block.get_selector(1, y)]);
+ pDst[2].set_rgb(subblock_colors1[block.get_selector(2, y)]);
+ pDst[3].set_rgb(subblock_colors1[block.get_selector(3, y)]);
+ pDst += 4;
+ }
+ }
+ }
+ else
+ {
+ if (flip_flag)
+ {
+ // 0000
+ // 0000
+ // 1111
+ // 1111
+ for (uint32_t y = 0; y < 2; y++)
+ {
+ pDst[0] = subblock_colors0[block.get_selector(0, y)];
+ pDst[1] = subblock_colors0[block.get_selector(1, y)];
+ pDst[2] = subblock_colors0[block.get_selector(2, y)];
+ pDst[3] = subblock_colors0[block.get_selector(3, y)];
+ pDst += 4;
+ }
+
+ for (uint32_t y = 2; y < 4; y++)
+ {
+ pDst[0] = subblock_colors1[block.get_selector(0, y)];
+ pDst[1] = subblock_colors1[block.get_selector(1, y)];
+ pDst[2] = subblock_colors1[block.get_selector(2, y)];
+ pDst[3] = subblock_colors1[block.get_selector(3, y)];
+ pDst += 4;
+ }
+ }
+ else
+ {
+ // 0011
+ // 0011
+ // 0011
+ // 0011
+ for (uint32_t y = 0; y < 4; y++)
+ {
+ pDst[0] = subblock_colors0[block.get_selector(0, y)];
+ pDst[1] = subblock_colors0[block.get_selector(1, y)];
+ pDst[2] = subblock_colors1[block.get_selector(2, y)];
+ pDst[3] = subblock_colors1[block.get_selector(3, y)];
+ pDst += 4;
+ }
+ }
+ }
+
+ return true;
+ }
+
+ inline int extend_6_to_8(uint32_t n)
+ {
+ return (n << 2) | (n >> 4);
+ }
+
+ inline int extend_7_to_8(uint32_t n)
+ {
+ return (n << 1) | (n >> 6);
+ }
+
+ inline int extend_4_to_8(uint32_t n)
+ {
+ return (n << 4) | n;
+ }
+
+ uint64_t etc_block::evaluate_etc1_error(const color_rgba* pBlock_pixels, bool perceptual, int subblock_index) const
+ {
+ color_rgba unpacked_block[16];
+
+ unpack_etc1(*this, unpacked_block);
+
+ uint64_t total_error = 0;
+
+ if (subblock_index < 0)
+ {
+ for (uint32_t i = 0; i < 16; i++)
+ total_error += color_distance(perceptual, pBlock_pixels[i], unpacked_block[i], false);
+ }
+ else
+ {
+ const bool flip_bit = get_flip_bit();
+
+ for (uint32_t i = 0; i < 8; i++)
+ {
+ const uint32_t idx = g_etc1_pixel_indices[flip_bit][subblock_index][i];
+
+ total_error += color_distance(perceptual, pBlock_pixels[idx], unpacked_block[idx], false);
+ }
+ }
+
+ return total_error;
+ }
+
+ void etc_block::get_subblock_pixels(color_rgba* pPixels, int subblock_index) const
+ {
+ if (subblock_index < 0)
+ unpack_etc1(*this, pPixels);
+ else
+ {
+ color_rgba unpacked_block[16];
+
+ unpack_etc1(*this, unpacked_block);
+
+ const bool flip_bit = get_flip_bit();
+
+ for (uint32_t i = 0; i < 8; i++)
+ {
+ const uint32_t idx = g_etc1_pixel_indices[flip_bit][subblock_index][i];
+
+ pPixels[i] = unpacked_block[idx];
+ }
+ }
+ }
+
+ bool etc1_optimizer::compute()
+ {
+ assert(m_pResult->m_pSelectors);
+
+ if (m_pParams->m_pForce_selectors)
+ {
+ assert(m_pParams->m_quality >= cETCQualitySlow);
+ if (m_pParams->m_quality < cETCQualitySlow)
+ return false;
+ }
+
+ const uint32_t n = m_pParams->m_num_src_pixels;
+
+ if (m_pParams->m_cluster_fit)
+ {
+ if (m_pParams->m_quality == cETCQualityFast)
+ compute_internal_cluster_fit(4);
+ else if (m_pParams->m_quality == cETCQualityMedium)
+ compute_internal_cluster_fit(16);
+ else if (m_pParams->m_quality == cETCQualitySlow)
+ compute_internal_cluster_fit(64);
+ else
+ compute_internal_cluster_fit(BASISU_ETC1_CLUSTER_FIT_ORDER_TABLE_SIZE);
+ }
+ else
+ compute_internal_neighborhood(m_br, m_bg, m_bb);
+
+ if (!m_best_solution.m_valid)
+ {
+ m_pResult->m_error = UINT32_MAX;
+ return false;
+ }
+
+ //const uint8_t* pSelectors = &m_best_solution.m_selectors[0];
+ const uint8_t* pSelectors = m_pParams->m_pForce_selectors ? m_pParams->m_pForce_selectors : &m_best_solution.m_selectors[0];
+
+#if defined(DEBUG) || defined(_DEBUG)
+ {
+ // sanity check the returned error
+ color_rgba block_colors[4];
+ m_best_solution.m_coords.get_block_colors(block_colors);
+
+ const color_rgba* pSrc_pixels = m_pParams->m_pSrc_pixels;
+ uint64_t actual_error = 0;
+
+ bool perceptual;
+ if (m_pParams->m_quality >= cETCQualityMedium)
+ perceptual = m_pParams->m_perceptual;
+ else
+ perceptual = (m_pParams->m_quality == cETCQualityFast) ? false : m_pParams->m_perceptual;
+
+ for (uint32_t i = 0; i < n; i++)
+ actual_error += color_distance(perceptual, pSrc_pixels[i], block_colors[pSelectors[i]], false);
+
+ assert(actual_error == m_best_solution.m_error);
+ }
+#endif
+
+ m_pResult->m_error = m_best_solution.m_error;
+
+ m_pResult->m_block_color_unscaled = m_best_solution.m_coords.m_unscaled_color;
+ m_pResult->m_block_color4 = m_best_solution.m_coords.m_color4;
+
+ m_pResult->m_block_inten_table = m_best_solution.m_coords.m_inten_table;
+ memcpy(m_pResult->m_pSelectors, pSelectors, n);
+ m_pResult->m_n = n;
+
+ return true;
+ }
+
+ void etc1_optimizer::refine_solution(uint32_t max_refinement_trials)
+ {
+ // Now we have the input block, the avg. color of the input pixels, a set of trial selector indices, and the block color+intensity index.
+ // Now, for each component, attempt to refine the current solution by solving a simple linear equation. For example, for 4 colors:
+ // The goal is:
+ // pixel0 - (block_color+inten_table[selector0]) + pixel1 - (block_color+inten_table[selector1]) + pixel2 - (block_color+inten_table[selector2]) + pixel3 - (block_color+inten_table[selector3]) = 0
+ // Rearranging this:
+ // (pixel0 + pixel1 + pixel2 + pixel3) - (block_color+inten_table[selector0]) - (block_color+inten_table[selector1]) - (block_color+inten_table[selector2]) - (block_color+inten_table[selector3]) = 0
+ // (pixel0 + pixel1 + pixel2 + pixel3) - block_color - inten_table[selector0] - block_color-inten_table[selector1] - block_color-inten_table[selector2] - block_color-inten_table[selector3] = 0
+ // (pixel0 + pixel1 + pixel2 + pixel3) - 4*block_color - inten_table[selector0] - inten_table[selector1] - inten_table[selector2] - inten_table[selector3] = 0
+ // (pixel0 + pixel1 + pixel2 + pixel3) - 4*block_color - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3]) = 0
+ // (pixel0 + pixel1 + pixel2 + pixel3)/4 - block_color - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3])/4 = 0
+ // block_color = (pixel0 + pixel1 + pixel2 + pixel3)/4 - (inten_table[selector0] + inten_table[selector1] + inten_table[selector2] + inten_table[selector3])/4
+ // So what this means:
+ // optimal_block_color = avg_input - avg_inten_delta
+ // So the optimal block color can be computed by taking the average block color and subtracting the current average of the intensity delta.
+ // Unfortunately, optimal_block_color must then be quantized to 555 or 444 so it's not always possible to improve matters using this formula.
+ // Also, the above formula is for unclamped intensity deltas. The actual implementation takes into account clamping.
+
+ const uint32_t n = m_pParams->m_num_src_pixels;
+
+ for (uint32_t refinement_trial = 0; refinement_trial < max_refinement_trials; refinement_trial++)
+ {
+ const uint8_t* pSelectors = &m_best_solution.m_selectors[0];
+ const int* pInten_table = g_etc1_inten_tables[m_best_solution.m_coords.m_inten_table];
+
+ int delta_sum_r = 0, delta_sum_g = 0, delta_sum_b = 0;
+ const color_rgba base_color(m_best_solution.m_coords.get_scaled_color());
+ for (uint32_t r = 0; r < n; r++)
+ {
+ const uint32_t s = *pSelectors++;
+ const int yd_temp = pInten_table[s];
+ // Compute actual delta being applied to each pixel, taking into account clamping.
+ delta_sum_r += clamp<int>(base_color.r + yd_temp, 0, 255) - base_color.r;
+ delta_sum_g += clamp<int>(base_color.g + yd_temp, 0, 255) - base_color.g;
+ delta_sum_b += clamp<int>(base_color.b + yd_temp, 0, 255) - base_color.b;
+ }
+
+ if ((!delta_sum_r) && (!delta_sum_g) && (!delta_sum_b))
+ break;
+
+ const float avg_delta_r_f = static_cast<float>(delta_sum_r) / n;
+ const float avg_delta_g_f = static_cast<float>(delta_sum_g) / n;
+ const float avg_delta_b_f = static_cast<float>(delta_sum_b) / n;
+ const int br1 = clamp<int>(static_cast<int32_t>((m_avg_color[0] - avg_delta_r_f) * m_limit / 255.0f + .5f), 0, m_limit);
+ const int bg1 = clamp<int>(static_cast<int32_t>((m_avg_color[1] - avg_delta_g_f) * m_limit / 255.0f + .5f), 0, m_limit);
+ const int bb1 = clamp<int>(static_cast<int32_t>((m_avg_color[2] - avg_delta_b_f) * m_limit / 255.0f + .5f), 0, m_limit);
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Refinement trial %u, avg_delta %f %f %f\n", refinement_trial, avg_delta_r_f, avg_delta_g_f, avg_delta_b_f);
+#endif
+
+ if (!evaluate_solution(etc1_solution_coordinates(br1, bg1, bb1, 0, m_pParams->m_use_color4), m_trial_solution, &m_best_solution))
+ break;
+
+ } // refinement_trial
+ }
+
+ void etc1_optimizer::compute_internal_neighborhood(int scan_r, int scan_g, int scan_b)
+ {
+ if (m_best_solution.m_error == 0)
+ return;
+
+ //const uint32_t n = m_pParams->m_num_src_pixels;
+ const int scan_delta_size = m_pParams->m_scan_delta_size;
+
+ // Scan through a subset of the 3D lattice centered around the avg block color trying each 3D (555 or 444) lattice point as a potential block color.
+ // Each time a better solution is found try to refine the current solution's block color based of the current selectors and intensity table index.
+ for (int zdi = 0; zdi < scan_delta_size; zdi++)
+ {
+ const int zd = m_pParams->m_pScan_deltas[zdi];
+ const int mbb = scan_b + zd;
+ if (mbb < 0) continue; else if (mbb > m_limit) break;
+
+ for (int ydi = 0; ydi < scan_delta_size; ydi++)
+ {
+ const int yd = m_pParams->m_pScan_deltas[ydi];
+ const int mbg = scan_g + yd;
+ if (mbg < 0) continue; else if (mbg > m_limit) break;
+
+ for (int xdi = 0; xdi < scan_delta_size; xdi++)
+ {
+ const int xd = m_pParams->m_pScan_deltas[xdi];
+ const int mbr = scan_r + xd;
+ if (mbr < 0) continue; else if (mbr > m_limit) break;
+
+ etc1_solution_coordinates coords(mbr, mbg, mbb, 0, m_pParams->m_use_color4);
+
+ if (!evaluate_solution(coords, m_trial_solution, &m_best_solution))
+ continue;
+
+ if (m_pParams->m_refinement)
+ {
+ refine_solution((m_pParams->m_quality == cETCQualityFast) ? 2 : (((xd | yd | zd) == 0) ? 4 : 2));
+ }
+
+ } // xdi
+ } // ydi
+ } // zdi
+ }
+
+ void etc1_optimizer::compute_internal_cluster_fit(uint32_t total_perms_to_try)
+ {
+ if ((!m_best_solution.m_valid) || ((m_br != m_best_solution.m_coords.m_unscaled_color.r) || (m_bg != m_best_solution.m_coords.m_unscaled_color.g) || (m_bb != m_best_solution.m_coords.m_unscaled_color.b)))
+ {
+ evaluate_solution(etc1_solution_coordinates(m_br, m_bg, m_bb, 0, m_pParams->m_use_color4), m_trial_solution, &m_best_solution);
+ }
+
+ if ((m_best_solution.m_error == 0) || (!m_best_solution.m_valid))
+ return;
+
+ for (uint32_t i = 0; i < total_perms_to_try; i++)
+ {
+ int delta_sum_r = 0, delta_sum_g = 0, delta_sum_b = 0;
+
+ const int *pInten_table = g_etc1_inten_tables[m_best_solution.m_coords.m_inten_table];
+ const color_rgba base_color(m_best_solution.m_coords.get_scaled_color());
+
+ const uint8_t *pNum_selectors = g_cluster_fit_order_tab[i].m_v;
+
+ for (uint32_t q = 0; q < 4; q++)
+ {
+ const int yd_temp = pInten_table[q];
+
+ delta_sum_r += pNum_selectors[q] * (clamp<int>(base_color.r + yd_temp, 0, 255) - base_color.r);
+ delta_sum_g += pNum_selectors[q] * (clamp<int>(base_color.g + yd_temp, 0, 255) - base_color.g);
+ delta_sum_b += pNum_selectors[q] * (clamp<int>(base_color.b + yd_temp, 0, 255) - base_color.b);
+ }
+
+ if ((!delta_sum_r) && (!delta_sum_g) && (!delta_sum_b))
+ continue;
+
+ const float avg_delta_r_f = static_cast<float>(delta_sum_r) / 8;
+ const float avg_delta_g_f = static_cast<float>(delta_sum_g) / 8;
+ const float avg_delta_b_f = static_cast<float>(delta_sum_b) / 8;
+
+ const int br1 = clamp<int>(static_cast<int32_t>((m_avg_color[0] - avg_delta_r_f) * m_limit / 255.0f + .5f), 0, m_limit);
+ const int bg1 = clamp<int>(static_cast<int32_t>((m_avg_color[1] - avg_delta_g_f) * m_limit / 255.0f + .5f), 0, m_limit);
+ const int bb1 = clamp<int>(static_cast<int32_t>((m_avg_color[2] - avg_delta_b_f) * m_limit / 255.0f + .5f), 0, m_limit);
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Second refinement trial %u, avg_delta %f %f %f\n", i, avg_delta_r_f, avg_delta_g_f, avg_delta_b_f);
+#endif
+
+ evaluate_solution(etc1_solution_coordinates(br1, bg1, bb1, 0, m_pParams->m_use_color4), m_trial_solution, &m_best_solution);
+
+ if (m_best_solution.m_error == 0)
+ break;
+ }
+ }
+
+ void etc1_optimizer::init(const params& params, results& result)
+ {
+ m_pParams = &params;
+ m_pResult = &result;
+
+ const uint32_t n = m_pParams->m_num_src_pixels;
+
+ m_selectors.resize(n);
+ m_best_selectors.resize(n);
+ m_temp_selectors.resize(n);
+ m_trial_solution.m_selectors.resize(n);
+ m_best_solution.m_selectors.resize(n);
+
+ m_limit = m_pParams->m_use_color4 ? 15 : 31;
+
+ vec3F avg_color(0.0f);
+
+ m_luma.resize(n);
+ m_sorted_luma_indices.resize(n);
+ m_sorted_luma.resize(n);
+
+ int min_r = 255, min_g = 255, min_b = 255;
+ int max_r = 0, max_g = 0, max_b = 0;
+
+ for (uint32_t i = 0; i < n; i++)
+ {
+ const color_rgba& c = m_pParams->m_pSrc_pixels[i];
+
+ min_r = basisu::minimum<int>(min_r, c.r);
+ min_g = basisu::minimum<int>(min_g, c.g);
+ min_b = basisu::minimum<int>(min_b, c.b);
+
+ max_r = basisu::maximum<int>(max_r, c.r);
+ max_g = basisu::maximum<int>(max_g, c.g);
+ max_b = basisu::maximum<int>(max_b, c.b);
+
+ const vec3F fc(c.r, c.g, c.b);
+
+ avg_color += fc;
+
+ m_luma[i] = static_cast<uint16_t>(c.r + c.g + c.b);
+ m_sorted_luma_indices[i] = i;
+ }
+ avg_color /= static_cast<float>(n);
+ m_avg_color = avg_color;
+ m_max_comp_spread = basisu::maximum(basisu::maximum(max_r - min_r, max_g - min_g), max_b - min_b);
+
+ m_br = clamp<int>(static_cast<uint32_t>(m_avg_color[0] * m_limit / 255.0f + .5f), 0, m_limit);
+ m_bg = clamp<int>(static_cast<uint32_t>(m_avg_color[1] * m_limit / 255.0f + .5f), 0, m_limit);
+ m_bb = clamp<int>(static_cast<uint32_t>(m_avg_color[2] * m_limit / 255.0f + .5f), 0, m_limit);
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Avg block color: %u %u %u\n", m_br, m_bg, m_bb);
+#endif
+
+ if (m_pParams->m_quality == cETCQualityFast)
+ {
+ indirect_sort(n, &m_sorted_luma_indices[0], &m_luma[0]);
+
+ m_pSorted_luma = &m_sorted_luma[0];
+ m_pSorted_luma_indices = &m_sorted_luma_indices[0];
+
+ for (uint32_t i = 0; i < n; i++)
+ m_pSorted_luma[i] = m_luma[m_pSorted_luma_indices[i]];
+ }
+
+ m_best_solution.m_coords.clear();
+ m_best_solution.m_valid = false;
+ m_best_solution.m_error = UINT64_MAX;
+
+ clear_obj(m_solutions_tried);
+ }
+
+ // Return false if we've probably already tried this solution, true if we have definitely not.
+ bool etc1_optimizer::check_for_redundant_solution(const etc1_solution_coordinates& coords)
+ {
+ // Hash first 3 bytes of color (RGB)
+ uint32_t kh = hash_hsieh((uint8_t*)&coords.m_unscaled_color.r, 3);
+
+ uint32_t h0 = kh & cSolutionsTriedHashMask;
+ uint32_t h1 = (kh >> cSolutionsTriedHashBits) & cSolutionsTriedHashMask;
+
+ // Simple Bloom filter lookup with k=2
+ if ( ((m_solutions_tried[h0 >> 3] & (1 << (h0 & 7))) != 0) &&
+ ((m_solutions_tried[h1 >> 3] & (1 << (h1 & 7))) != 0) )
+ return false;
+
+ m_solutions_tried[h0 >> 3] |= (1 << (h0 & 7));
+ m_solutions_tried[h1 >> 3] |= (1 << (h1 & 7));
+
+ return true;
+ }
+
+ static uint8_t g_eval_dist_tables[8][256] =
+ {
+ // 99% threshold
+ { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,},
+ { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,},
+ { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,},
+ { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,0,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,},
+ { 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,0,1,},
+ { 1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,1,0,0,0,0,1,0,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,0,0,0,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,},
+ { 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,0,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,},
+ { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,1,1,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,}
+ };
+
+ bool etc1_optimizer::evaluate_solution_slow(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution)
+ {
+ if (!check_for_redundant_solution(coords))
+ return false;
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval solution: %u %u %u\n", coords.m_unscaled_color.r, coords.m_unscaled_color.g, coords.m_unscaled_color.b);
+#endif
+
+ trial_solution.m_valid = false;
+
+ if (m_pParams->m_constrain_against_base_color5)
+ {
+ const int dr = (int)coords.m_unscaled_color.r - (int)m_pParams->m_base_color5.r;
+ const int dg = (int)coords.m_unscaled_color.g - (int)m_pParams->m_base_color5.g;
+ const int db = (int)coords.m_unscaled_color.b - (int)m_pParams->m_base_color5.b;
+
+ if ((minimum(dr, dg, db) < cETC1ColorDeltaMin) || (maximum(dr, dg, db) > cETC1ColorDeltaMax))
+ {
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval failed due to constraint from %u %u %u\n", m_pParams->m_base_color5.r, m_pParams->m_base_color5.g, m_pParams->m_base_color5.b);
+#endif
+ return false;
+ }
+ }
+
+ const color_rgba base_color(coords.get_scaled_color());
+
+ const uint32_t n = m_pParams->m_num_src_pixels;
+ assert(trial_solution.m_selectors.size() == n);
+
+ trial_solution.m_error = INT64_MAX;
+
+ const uint8_t *pSelectors_to_use = m_pParams->m_pForce_selectors;
+
+ for (uint32_t inten_table = 0; inten_table < cETC1IntenModifierValues; inten_table++)
+ {
+ if (m_pParams->m_quality <= cETCQualityMedium)
+ {
+ if (!g_eval_dist_tables[inten_table][m_max_comp_spread])
+ continue;
+ }
+#if 0
+ if (m_pParams->m_quality <= cETCQualityMedium)
+ {
+ // For tables 5-7, if the max component spread falls within certain ranges, skip the inten table. Statistically they are extremely unlikely to result in lower error.
+ if (inten_table == 7)
+ {
+ if (m_max_comp_spread < 42)
+ continue;
+ }
+ else if (inten_table == 6)
+ {
+ if ((m_max_comp_spread >= 12) && (m_max_comp_spread <= 31))
+ continue;
+ }
+ else if (inten_table == 5)
+ {
+ if ((m_max_comp_spread >= 13) && (m_max_comp_spread <= 21))
+ continue;
+ }
+ }
+#endif
+
+ const int* pInten_table = g_etc1_inten_tables[inten_table];
+
+ color_rgba block_colors[4];
+ for (uint32_t s = 0; s < 4; s++)
+ {
+ const int yd = pInten_table[s];
+ block_colors[s].set(base_color.r + yd, base_color.g + yd, base_color.b + yd, 255);
+ }
+
+ uint64_t total_error = 0;
+
+ const color_rgba* pSrc_pixels = m_pParams->m_pSrc_pixels;
+
+ if (!g_cpu_supports_sse41)
+ {
+ for (uint32_t c = 0; c < n; c++)
+ {
+ const color_rgba& src_pixel = *pSrc_pixels++;
+
+ uint32_t best_selector_index = 0;
+ uint32_t best_error = 0;
+
+ if (pSelectors_to_use)
+ {
+ best_selector_index = pSelectors_to_use[c];
+ best_error = color_distance(m_pParams->m_perceptual, src_pixel, block_colors[best_selector_index], false);
+ }
+ else
+ {
+ best_error = color_distance(m_pParams->m_perceptual, src_pixel, block_colors[0], false);
+
+ uint32_t trial_error = color_distance(m_pParams->m_perceptual, src_pixel, block_colors[1], false);
+ if (trial_error < best_error)
+ {
+ best_error = trial_error;
+ best_selector_index = 1;
+ }
+
+ trial_error = color_distance(m_pParams->m_perceptual, src_pixel, block_colors[2], false);
+ if (trial_error < best_error)
+ {
+ best_error = trial_error;
+ best_selector_index = 2;
+ }
+
+ trial_error = color_distance(m_pParams->m_perceptual, src_pixel, block_colors[3], false);
+ if (trial_error < best_error)
+ {
+ best_error = trial_error;
+ best_selector_index = 3;
+ }
+ }
+
+ m_temp_selectors[c] = static_cast<uint8_t>(best_selector_index);
+
+ total_error += best_error;
+ if (total_error >= trial_solution.m_error)
+ break;
+ }
+ }
+ else
+ {
+#if BASISU_SUPPORT_SSE
+ if (pSelectors_to_use)
+ {
+ if (m_pParams->m_perceptual)
+ perceptual_distance_rgb_4_N_sse41((int64_t*)&total_error, pSelectors_to_use, block_colors, pSrc_pixels, n, trial_solution.m_error);
+ else
+ linear_distance_rgb_4_N_sse41((int64_t*)&total_error, pSelectors_to_use, block_colors, pSrc_pixels, n, trial_solution.m_error);
+ }
+ else
+ {
+ if (m_pParams->m_perceptual)
+ find_selectors_perceptual_rgb_4_N_sse41((int64_t*)&total_error, &m_temp_selectors[0], block_colors, pSrc_pixels, n, trial_solution.m_error);
+ else
+ find_selectors_linear_rgb_4_N_sse41((int64_t*)&total_error, &m_temp_selectors[0], block_colors, pSrc_pixels, n, trial_solution.m_error);
+ }
+#endif
+ }
+
+ if (total_error < trial_solution.m_error)
+ {
+ trial_solution.m_error = total_error;
+ trial_solution.m_coords.m_inten_table = inten_table;
+ trial_solution.m_selectors.swap(m_temp_selectors);
+ trial_solution.m_valid = true;
+ }
+ }
+ trial_solution.m_coords.m_unscaled_color = coords.m_unscaled_color;
+ trial_solution.m_coords.m_color4 = m_pParams->m_use_color4;
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval done: %u error: %I64u best error so far: %I64u\n", (trial_solution.m_error < pBest_solution->m_error), trial_solution.m_error, pBest_solution->m_error);
+#endif
+
+ bool success = false;
+ if (pBest_solution)
+ {
+ if (trial_solution.m_error < pBest_solution->m_error)
+ {
+ *pBest_solution = trial_solution;
+ success = true;
+ }
+ }
+
+ return success;
+ }
+
+ bool etc1_optimizer::evaluate_solution_fast(const etc1_solution_coordinates& coords, potential_solution& trial_solution, potential_solution* pBest_solution)
+ {
+ if (!check_for_redundant_solution(coords))
+ return false;
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval solution fast: %u %u %u\n", coords.m_unscaled_color.r, coords.m_unscaled_color.g, coords.m_unscaled_color.b);
+#endif
+
+ if (m_pParams->m_constrain_against_base_color5)
+ {
+ const int dr = (int)coords.m_unscaled_color.r - (int)m_pParams->m_base_color5.r;
+ const int dg = (int)coords.m_unscaled_color.g - (int)m_pParams->m_base_color5.g;
+ const int db = (int)coords.m_unscaled_color.b - (int)m_pParams->m_base_color5.b;
+
+ if ((minimum(dr, dg, db) < cETC1ColorDeltaMin) || (maximum(dr, dg, db) > cETC1ColorDeltaMax))
+ {
+ trial_solution.m_valid = false;
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval failed due to constraint from %u %u %u\n", m_pParams->m_base_color5.r, m_pParams->m_base_color5.g, m_pParams->m_base_color5.b);
+#endif
+ return false;
+ }
+ }
+
+ const color_rgba base_color(coords.get_scaled_color());
+
+ const uint32_t n = m_pParams->m_num_src_pixels;
+ assert(trial_solution.m_selectors.size() == n);
+
+ trial_solution.m_error = UINT64_MAX;
+
+ const bool perceptual = (m_pParams->m_quality == cETCQualityFast) ? false : m_pParams->m_perceptual;
+
+ for (int inten_table = cETC1IntenModifierValues - 1; inten_table >= 0; --inten_table)
+ {
+ const int* pInten_table = g_etc1_inten_tables[inten_table];
+
+ uint32_t block_inten[4];
+ color_rgba block_colors[4];
+ for (uint32_t s = 0; s < 4; s++)
+ {
+ const int yd = pInten_table[s];
+ color_rgba block_color(base_color.r + yd, base_color.g + yd, base_color.b + yd, 255);
+ block_colors[s] = block_color;
+ block_inten[s] = block_color.r + block_color.g + block_color.b;
+ }
+
+ // evaluate_solution_fast() enforces/assumes a total ordering of the input colors along the intensity (1,1,1) axis to more quickly classify the inputs to selectors.
+ // The inputs colors have been presorted along the projection onto this axis, and ETC1 block colors are always ordered along the intensity axis, so this classification is fast.
+ // 0 1 2 3
+ // 01 12 23
+ const uint32_t block_inten_midpoints[3] = { block_inten[0] + block_inten[1], block_inten[1] + block_inten[2], block_inten[2] + block_inten[3] };
+
+ uint64_t total_error = 0;
+ const color_rgba* pSrc_pixels = m_pParams->m_pSrc_pixels;
+
+ if (perceptual)
+ {
+ if ((m_pSorted_luma[n - 1] * 2) < block_inten_midpoints[0])
+ {
+ if (block_inten[0] > m_pSorted_luma[n - 1])
+ {
+ const uint32_t min_error = iabs((int)block_inten[0] - (int)m_pSorted_luma[n - 1]);
+ if (min_error >= trial_solution.m_error)
+ continue;
+ }
+
+ memset(&m_temp_selectors[0], 0, n);
+
+ for (uint32_t c = 0; c < n; c++)
+ total_error += color_distance(true, block_colors[0], pSrc_pixels[c], false);
+ }
+ else if ((m_pSorted_luma[0] * 2) >= block_inten_midpoints[2])
+ {
+ if (m_pSorted_luma[0] > block_inten[3])
+ {
+ const uint32_t min_error = iabs((int)m_pSorted_luma[0] - (int)block_inten[3]);
+ if (min_error >= trial_solution.m_error)
+ continue;
+ }
+
+ memset(&m_temp_selectors[0], 3, n);
+
+ for (uint32_t c = 0; c < n; c++)
+ total_error += color_distance(true, block_colors[3], pSrc_pixels[c], false);
+ }
+ else
+ {
+ if (!g_cpu_supports_sse41)
+ {
+ uint32_t cur_selector = 0, c;
+ for (c = 0; c < n; c++)
+ {
+ const uint32_t y = m_pSorted_luma[c];
+ while ((y * 2) >= block_inten_midpoints[cur_selector])
+ if (++cur_selector > 2)
+ goto done;
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = static_cast<uint8_t>(cur_selector);
+ total_error += color_distance(true, block_colors[cur_selector], pSrc_pixels[sorted_pixel_index], false);
+ }
+ done:
+ while (c < n)
+ {
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = 3;
+ total_error += color_distance(true, block_colors[3], pSrc_pixels[sorted_pixel_index], false);
+ ++c;
+ }
+ }
+ else
+ {
+#if BASISU_SUPPORT_SSE
+ uint32_t cur_selector = 0, c;
+
+ for (c = 0; c < n; c++)
+ {
+ const uint32_t y = m_pSorted_luma[c];
+ while ((y * 2) >= block_inten_midpoints[cur_selector])
+ {
+ if (++cur_selector > 2)
+ goto done3;
+ }
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = static_cast<uint8_t>(cur_selector);
+ }
+ done3:
+
+ while (c < n)
+ {
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = 3;
+ ++c;
+ }
+
+ int64_t block_error;
+ perceptual_distance_rgb_4_N_sse41(&block_error, &m_temp_selectors[0], block_colors, pSrc_pixels, n, INT64_MAX);
+ total_error += block_error;
+#endif
+ }
+ }
+ }
+ else
+ {
+ if ((m_pSorted_luma[n - 1] * 2) < block_inten_midpoints[0])
+ {
+ if (block_inten[0] > m_pSorted_luma[n - 1])
+ {
+ const uint32_t min_error = iabs((int)block_inten[0] - (int)m_pSorted_luma[n - 1]);
+ if (min_error >= trial_solution.m_error)
+ continue;
+ }
+
+ memset(&m_temp_selectors[0], 0, n);
+
+ for (uint32_t c = 0; c < n; c++)
+ total_error += color_distance(block_colors[0], pSrc_pixels[c], false);
+ }
+ else if ((m_pSorted_luma[0] * 2) >= block_inten_midpoints[2])
+ {
+ if (m_pSorted_luma[0] > block_inten[3])
+ {
+ const uint32_t min_error = iabs((int)m_pSorted_luma[0] - (int)block_inten[3]);
+ if (min_error >= trial_solution.m_error)
+ continue;
+ }
+
+ memset(&m_temp_selectors[0], 3, n);
+
+ for (uint32_t c = 0; c < n; c++)
+ total_error += color_distance(block_colors[3], pSrc_pixels[c], false);
+ }
+ else
+ {
+ uint32_t cur_selector = 0, c;
+ for (c = 0; c < n; c++)
+ {
+ const uint32_t y = m_pSorted_luma[c];
+ while ((y * 2) >= block_inten_midpoints[cur_selector])
+ if (++cur_selector > 2)
+ goto done2;
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = static_cast<uint8_t>(cur_selector);
+ total_error += color_distance(block_colors[cur_selector], pSrc_pixels[sorted_pixel_index], false);
+ }
+ done2:
+ while (c < n)
+ {
+ const uint32_t sorted_pixel_index = m_pSorted_luma_indices[c];
+ m_temp_selectors[sorted_pixel_index] = 3;
+ total_error += color_distance(block_colors[3], pSrc_pixels[sorted_pixel_index], false);
+ ++c;
+ }
+ }
+ }
+
+ if (total_error < trial_solution.m_error)
+ {
+ trial_solution.m_error = total_error;
+ trial_solution.m_coords.m_inten_table = inten_table;
+ trial_solution.m_selectors.swap(m_temp_selectors);
+ trial_solution.m_valid = true;
+ if (!total_error)
+ break;
+ }
+ }
+ trial_solution.m_coords.m_unscaled_color = coords.m_unscaled_color;
+ trial_solution.m_coords.m_color4 = m_pParams->m_use_color4;
+
+#if BASISU_DEBUG_ETC_ENCODER_DEEPER
+ printf("Eval done: %u error: %I64u best error so far: %I64u\n", (trial_solution.m_error < pBest_solution->m_error), trial_solution.m_error, pBest_solution->m_error);
+#endif
+
+ bool success = false;
+ if (pBest_solution)
+ {
+ if (trial_solution.m_error < pBest_solution->m_error)
+ {
+ *pBest_solution = trial_solution;
+ success = true;
+ }
+ }
+
+ return success;
+ }
+
+ uint64_t pack_eac_a8(pack_eac_a8_results& results, const uint8_t* pPixels, uint32_t num_pixels, uint32_t base_search_rad, uint32_t mul_search_rad, uint32_t table_mask)
+ {
+ results.m_selectors.resize(num_pixels);
+ results.m_selectors_temp.resize(num_pixels);
+
+ uint32_t min_alpha = 255, max_alpha = 0;
+ for (uint32_t i = 0; i < num_pixels; i++)
+ {
+ const uint32_t a = pPixels[i];
+ if (a < min_alpha) min_alpha = a;
+ if (a > max_alpha) max_alpha = a;
+ }
+
+ if (min_alpha == max_alpha)
+ {
+ results.m_base = min_alpha;
+ results.m_table = 13;
+ results.m_multiplier = 1;
+ for (uint32_t i = 0; i < num_pixels; i++)
+ results.m_selectors[i] = 4;
+ return 0;
+ }
+
+ const uint32_t alpha_range = max_alpha - min_alpha;
+
+ uint64_t best_err = UINT64_MAX;
+
+ for (uint32_t table = 0; table < 16; table++)
+ {
+ if ((table_mask & (1U << table)) == 0)
+ continue;
+
+ const float range = (float)(g_etc2_eac_tables[table][ETC2_EAC_MAX_VALUE_SELECTOR] - g_etc2_eac_tables[table][ETC2_EAC_MIN_VALUE_SELECTOR]);
+ const int center = (int)roundf(lerp((float)min_alpha, (float)max_alpha, (float)(0 - g_etc2_eac_tables[table][ETC2_EAC_MIN_VALUE_SELECTOR]) / range));
+
+ const int base_min = clamp255(center - base_search_rad);
+ const int base_max = clamp255(center + base_search_rad);
+
+ const int mul = (int)roundf(alpha_range / range);
+ const int mul_low = clamp<int>(mul - mul_search_rad, 1, 15);
+ const int mul_high = clamp<int>(mul + mul_search_rad, 1, 15);
+
+ for (int base = base_min; base <= base_max; base++)
+ {
+ for (int multiplier = mul_low; multiplier <= mul_high; multiplier++)
+ {
+ uint64_t total_err = 0;
+
+ for (uint32_t i = 0; i < num_pixels; i++)
+ {
+ const int a = pPixels[i];
+
+ uint32_t best_s_err = UINT32_MAX;
+ uint32_t best_s = 0;
+ for (uint32_t s = 0; s < 8; s++)
+ {
+ const int v = clamp255((int)multiplier * g_etc2_eac_tables[table][s] + (int)base);
+
+ uint32_t err = iabs(a - v);
+ if (err < best_s_err)
+ {
+ best_s_err = err;
+ best_s = s;
+ }
+ }
+
+ results.m_selectors_temp[i] = static_cast<uint8_t>(best_s);
+
+ total_err += best_s_err * best_s_err;
+ if (total_err >= best_err)
+ break;
+ }
+
+ if (total_err < best_err)
+ {
+ best_err = total_err;
+ results.m_base = base;
+ results.m_multiplier = multiplier;
+ results.m_table = table;
+ results.m_selectors.swap(results.m_selectors_temp);
+ if (!best_err)
+ return best_err;
+ }
+
+ } // table
+
+ } // multiplier
+
+ } // base
+
+ return best_err;
+ }
+
+ void pack_eac_a8(eac_a8_block* pBlock, const uint8_t* pPixels, uint32_t base_search_rad, uint32_t mul_search_rad, uint32_t table_mask)
+ {
+ pack_eac_a8_results results;
+ pack_eac_a8(results, pPixels, 16, base_search_rad, mul_search_rad, table_mask);
+
+ pBlock->m_base = results.m_base;
+ pBlock->m_multiplier = results.m_multiplier;
+ pBlock->m_table = results.m_table;
+ for (uint32_t y = 0; y < 4; y++)
+ for (uint32_t x = 0; x < 4; x++)
+ pBlock->set_selector(x, y, results.m_selectors[x + y * 4]);
+ }
+
+} // namespace basisu
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