stb_dxt: Better error calc for single-color table

Don't truncate error as aggressively; easily done, but wanted
to keep it separate from the previous change.
This commit is contained in:
Fabian Giesen 2021-07-01 16:24:09 -07:00
parent d84beeeff3
commit 425c4d8b31
1 changed files with 66 additions and 66 deletions

132
stb_dxt.h
View File

@ -134,72 +134,72 @@ static const unsigned char stb__QuantGTab[256 + 16] = {
247, 251, 251, 251, 251, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
};
static const unsigned char stb__OMatch5[256][2] = {
{ 0, 0 }, { 0, 0 }, { 0, 1 }, { 0, 1 }, { 1, 0 }, { 1, 0 }, { 1, 0 }, { 1, 1 },
{ 1, 1 }, { 2, 0 }, { 2, 0 }, { 0, 4 }, { 2, 1 }, { 2, 1 }, { 2, 1 }, { 3, 0 },
{ 3, 0 }, { 3, 0 }, { 3, 1 }, { 1, 5 }, { 3, 2 }, { 3, 2 }, { 4, 0 }, { 4, 0 },
{ 4, 1 }, { 4, 1 }, { 4, 2 }, { 4, 2 }, { 4, 2 }, { 3, 5 }, { 5, 1 }, { 5, 1 },
{ 5, 2 }, { 4, 4 }, { 5, 3 }, { 5, 3 }, { 5, 3 }, { 6, 2 }, { 6, 2 }, { 6, 2 },
{ 6, 3 }, { 5, 5 }, { 6, 4 }, { 6, 4 }, { 4, 8 }, { 7, 3 }, { 7, 3 }, { 7, 3 },
{ 7, 4 }, { 7, 4 }, { 7, 4 }, { 7, 5 }, { 5, 9 }, { 7, 6 }, { 7, 6 }, { 8, 4 },
{ 8, 4 }, { 8, 5 }, { 8, 5 }, { 8, 6 }, { 8, 6 }, { 8, 6 }, { 7, 9 }, { 9, 5 },
{ 9, 5 }, { 9, 6 }, { 8, 8 }, { 9, 7 }, { 9, 7 }, { 9, 7 }, { 10, 6 }, { 10, 6 },
{ 10, 6 }, { 10, 7 }, { 9, 9 }, { 10, 8 }, { 10, 8 }, { 8, 12 }, { 11, 7 }, { 11, 7 },
{ 11, 7 }, { 11, 8 }, { 11, 8 }, { 11, 8 }, { 11, 9 }, { 9, 13 }, { 11, 10 }, { 11, 10 },
{ 12, 8 }, { 12, 8 }, { 12, 9 }, { 12, 9 }, { 12, 10 }, { 12, 10 }, { 12, 10 }, { 11, 13 },
{ 13, 9 }, { 13, 9 }, { 13, 10 }, { 12, 12 }, { 13, 11 }, { 13, 11 }, { 13, 11 }, { 14, 10 },
{ 14, 10 }, { 14, 10 }, { 14, 11 }, { 13, 13 }, { 14, 12 }, { 14, 12 }, { 12, 16 }, { 15, 11 },
{ 15, 11 }, { 15, 11 }, { 15, 12 }, { 15, 12 }, { 15, 12 }, { 15, 13 }, { 13, 17 }, { 15, 14 },
{ 15, 14 }, { 16, 12 }, { 16, 12 }, { 16, 13 }, { 16, 13 }, { 16, 14 }, { 16, 14 }, { 16, 14 },
{ 15, 17 }, { 17, 13 }, { 17, 13 }, { 17, 14 }, { 16, 16 }, { 17, 15 }, { 17, 15 }, { 17, 15 },
{ 18, 14 }, { 18, 14 }, { 18, 14 }, { 18, 15 }, { 17, 17 }, { 18, 16 }, { 18, 16 }, { 16, 20 },
{ 19, 15 }, { 19, 15 }, { 19, 15 }, { 19, 16 }, { 19, 16 }, { 19, 16 }, { 19, 17 }, { 17, 21 },
{ 19, 18 }, { 19, 18 }, { 20, 16 }, { 20, 16 }, { 20, 17 }, { 20, 17 }, { 20, 18 }, { 20, 18 },
{ 20, 18 }, { 19, 21 }, { 21, 17 }, { 21, 17 }, { 21, 18 }, { 20, 20 }, { 21, 19 }, { 21, 19 },
{ 21, 19 }, { 22, 18 }, { 22, 18 }, { 22, 18 }, { 22, 19 }, { 21, 21 }, { 22, 20 }, { 22, 20 },
{ 20, 24 }, { 23, 19 }, { 23, 19 }, { 23, 19 }, { 23, 20 }, { 23, 20 }, { 23, 20 }, { 23, 21 },
{ 21, 25 }, { 23, 22 }, { 23, 22 }, { 24, 20 }, { 24, 20 }, { 24, 21 }, { 24, 21 }, { 24, 22 },
{ 24, 22 }, { 24, 22 }, { 23, 25 }, { 25, 21 }, { 25, 21 }, { 25, 22 }, { 24, 24 }, { 25, 23 },
{ 25, 23 }, { 25, 23 }, { 26, 22 }, { 26, 22 }, { 26, 22 }, { 26, 23 }, { 25, 25 }, { 26, 24 },
{ 26, 24 }, { 24, 28 }, { 27, 23 }, { 27, 23 }, { 27, 23 }, { 27, 24 }, { 27, 24 }, { 27, 24 },
{ 27, 25 }, { 25, 29 }, { 27, 26 }, { 27, 26 }, { 28, 24 }, { 28, 24 }, { 28, 25 }, { 28, 25 },
{ 28, 26 }, { 28, 26 }, { 28, 26 }, { 27, 29 }, { 29, 25 }, { 29, 25 }, { 29, 26 }, { 28, 28 },
{ 29, 27 }, { 29, 27 }, { 29, 27 }, { 30, 26 }, { 30, 26 }, { 30, 26 }, { 30, 27 }, { 29, 29 },
{ 30, 28 }, { 30, 28 }, { 30, 28 }, { 31, 27 }, { 31, 27 }, { 31, 27 }, { 31, 28 }, { 31, 28 },
{ 31, 28 }, { 31, 29 }, { 31, 29 }, { 31, 30 }, { 31, 30 }, { 31, 30 }, { 31, 31 }, { 31, 31 },
{ 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 }, { 2, 2 }, { 2, 2 }, { 2, 2 },
{ 2, 2 }, { 2, 2 }, { 2, 2 }, { 2, 2 }, { 2, 2 }, { 3, 3 }, { 3, 3 }, { 3, 3 },
{ 3, 3 }, { 3, 3 }, { 3, 3 }, { 3, 3 }, { 3, 3 }, { 4, 4 }, { 4, 4 }, { 4, 4 },
{ 4, 4 }, { 4, 4 }, { 4, 4 }, { 4, 4 }, { 4, 4 }, { 4, 4 }, { 5, 5 }, { 5, 5 },
{ 5, 5 }, { 5, 5 }, { 5, 5 }, { 5, 5 }, { 5, 5 }, { 5, 5 }, { 6, 6 }, { 6, 6 },
{ 6, 6 }, { 6, 6 }, { 6, 6 }, { 6, 6 }, { 6, 6 }, { 6, 6 }, { 7, 7 }, { 7, 7 },
{ 7, 7 }, { 7, 7 }, { 7, 7 }, { 7, 7 }, { 7, 7 }, { 7, 7 }, { 8, 8 }, { 8, 8 },
{ 8, 8 }, { 8, 8 }, { 8, 8 }, { 8, 8 }, { 8, 8 }, { 8, 8 }, { 8, 8 }, { 9, 9 },
{ 9, 9 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 10, 10 },
{ 10, 10 }, { 10, 10 }, { 10, 10 }, { 10, 10 }, { 10, 10 }, { 10, 10 }, { 10, 10 }, { 11, 11 },
{ 11, 11 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 12, 12 },
{ 12, 12 }, { 12, 12 }, { 12, 12 }, { 12, 12 }, { 12, 12 }, { 12, 12 }, { 12, 12 }, { 12, 12 },
{ 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 },
{ 14, 14 }, { 14, 14 }, { 14, 14 }, { 14, 14 }, { 14, 14 }, { 14, 14 }, { 14, 14 }, { 14, 14 },
{ 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 },
{ 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 },
{ 16, 16 }, { 17, 17 }, { 17, 17 }, { 17, 17 }, { 17, 17 }, { 17, 17 }, { 17, 17 }, { 17, 17 },
{ 17, 17 }, { 18, 18 }, { 18, 18 }, { 18, 18 }, { 18, 18 }, { 18, 18 }, { 18, 18 }, { 18, 18 },
{ 18, 18 }, { 19, 19 }, { 19, 19 }, { 19, 19 }, { 19, 19 }, { 19, 19 }, { 19, 19 }, { 19, 19 },
{ 19, 19 }, { 20, 20 }, { 20, 20 }, { 20, 20 }, { 20, 20 }, { 20, 20 }, { 20, 20 }, { 20, 20 },
{ 20, 20 }, { 20, 20 }, { 21, 21 }, { 21, 21 }, { 21, 21 }, { 21, 21 }, { 21, 21 }, { 21, 21 },
{ 21, 21 }, { 21, 21 }, { 22, 22 }, { 22, 22 }, { 22, 22 }, { 22, 22 }, { 22, 22 }, { 22, 22 },
{ 22, 22 }, { 22, 22 }, { 23, 23 }, { 23, 23 }, { 23, 23 }, { 23, 23 }, { 23, 23 }, { 23, 23 },
{ 23, 23 }, { 23, 23 }, { 24, 24 }, { 24, 24 }, { 24, 24 }, { 24, 24 }, { 24, 24 }, { 24, 24 },
{ 24, 24 }, { 24, 24 }, { 24, 24 }, { 25, 25 }, { 25, 25 }, { 25, 25 }, { 25, 25 }, { 25, 25 },
{ 25, 25 }, { 25, 25 }, { 25, 25 }, { 26, 26 }, { 26, 26 }, { 26, 26 }, { 26, 26 }, { 26, 26 },
{ 26, 26 }, { 26, 26 }, { 26, 26 }, { 27, 27 }, { 27, 27 }, { 27, 27 }, { 27, 27 }, { 27, 27 },
{ 27, 27 }, { 27, 27 }, { 27, 27 }, { 28, 28 }, { 28, 28 }, { 28, 28 }, { 28, 28 }, { 28, 28 },
{ 28, 28 }, { 28, 28 }, { 28, 28 }, { 28, 28 }, { 29, 29 }, { 29, 29 }, { 29, 29 }, { 29, 29 },
{ 29, 29 }, { 29, 29 }, { 29, 29 }, { 29, 29 }, { 30, 30 }, { 30, 30 }, { 30, 30 }, { 30, 30 },
{ 30, 30 }, { 30, 30 }, { 30, 30 }, { 30, 30 }, { 31, 31 }, { 31, 31 }, { 31, 31 }, { 31, 31 },
};
static const unsigned char stb__OMatch6[256][2] = {
{ 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 0 }, { 1, 1 }, { 2, 0 }, { 2, 1 }, { 3, 0 },
{ 3, 0 }, { 3, 1 }, { 4, 0 }, { 4, 0 }, { 4, 1 }, { 5, 0 }, { 5, 1 }, { 6, 0 },
{ 6, 0 }, { 6, 1 }, { 7, 0 }, { 7, 0 }, { 7, 1 }, { 8, 0 }, { 8, 1 }, { 8, 1 },
{ 8, 2 }, { 9, 1 }, { 9, 2 }, { 9, 2 }, { 9, 3 }, { 10, 2 }, { 10, 3 }, { 10, 3 },
{ 10, 4 }, { 11, 3 }, { 11, 4 }, { 11, 4 }, { 11, 5 }, { 12, 4 }, { 12, 5 }, { 12, 5 },
{ 12, 6 }, { 13, 5 }, { 13, 6 }, { 8, 16 }, { 13, 7 }, { 14, 6 }, { 14, 7 }, { 9, 17 },
{ 14, 8 }, { 15, 7 }, { 15, 8 }, { 11, 16 }, { 15, 9 }, { 15, 10 }, { 16, 8 }, { 16, 9 },
{ 16, 10 }, { 15, 13 }, { 17, 9 }, { 17, 10 }, { 17, 11 }, { 15, 16 }, { 18, 10 }, { 18, 11 },
{ 18, 12 }, { 16, 16 }, { 19, 11 }, { 19, 12 }, { 19, 13 }, { 17, 17 }, { 20, 12 }, { 20, 13 },
{ 20, 14 }, { 19, 16 }, { 21, 13 }, { 21, 14 }, { 21, 15 }, { 20, 17 }, { 22, 14 }, { 22, 15 },
{ 25, 10 }, { 22, 16 }, { 23, 15 }, { 23, 16 }, { 26, 11 }, { 23, 17 }, { 24, 16 }, { 24, 17 },
{ 27, 12 }, { 24, 18 }, { 25, 17 }, { 25, 18 }, { 28, 13 }, { 25, 19 }, { 26, 18 }, { 26, 19 },
{ 29, 14 }, { 26, 20 }, { 27, 19 }, { 27, 20 }, { 30, 15 }, { 27, 21 }, { 28, 20 }, { 28, 21 },
{ 28, 21 }, { 28, 22 }, { 29, 21 }, { 29, 22 }, { 24, 32 }, { 29, 23 }, { 30, 22 }, { 30, 23 },
{ 25, 33 }, { 30, 24 }, { 31, 23 }, { 31, 24 }, { 27, 32 }, { 31, 25 }, { 31, 26 }, { 32, 24 },
{ 32, 25 }, { 32, 26 }, { 31, 29 }, { 33, 25 }, { 33, 26 }, { 33, 27 }, { 31, 32 }, { 34, 26 },
{ 34, 27 }, { 34, 28 }, { 32, 32 }, { 35, 27 }, { 35, 28 }, { 35, 29 }, { 33, 33 }, { 36, 28 },
{ 36, 29 }, { 36, 30 }, { 35, 32 }, { 37, 29 }, { 37, 30 }, { 37, 31 }, { 36, 33 }, { 38, 30 },
{ 38, 31 }, { 41, 26 }, { 38, 32 }, { 39, 31 }, { 39, 32 }, { 42, 27 }, { 39, 33 }, { 40, 32 },
{ 40, 33 }, { 43, 28 }, { 40, 34 }, { 41, 33 }, { 41, 34 }, { 44, 29 }, { 41, 35 }, { 42, 34 },
{ 42, 35 }, { 45, 30 }, { 42, 36 }, { 43, 35 }, { 43, 36 }, { 46, 31 }, { 43, 37 }, { 44, 36 },
{ 44, 37 }, { 44, 37 }, { 44, 38 }, { 45, 37 }, { 45, 38 }, { 40, 48 }, { 45, 39 }, { 46, 38 },
{ 46, 39 }, { 41, 49 }, { 46, 40 }, { 47, 39 }, { 47, 40 }, { 43, 48 }, { 47, 41 }, { 47, 42 },
{ 48, 40 }, { 48, 41 }, { 48, 42 }, { 47, 45 }, { 49, 41 }, { 49, 42 }, { 49, 43 }, { 47, 48 },
{ 50, 42 }, { 50, 43 }, { 50, 44 }, { 48, 48 }, { 51, 43 }, { 51, 44 }, { 51, 45 }, { 49, 49 },
{ 52, 44 }, { 52, 45 }, { 52, 46 }, { 51, 48 }, { 53, 45 }, { 53, 46 }, { 53, 47 }, { 52, 49 },
{ 54, 46 }, { 54, 47 }, { 57, 42 }, { 54, 48 }, { 55, 47 }, { 55, 48 }, { 58, 43 }, { 55, 49 },
{ 56, 48 }, { 56, 49 }, { 59, 44 }, { 56, 50 }, { 57, 49 }, { 57, 50 }, { 60, 45 }, { 57, 51 },
{ 58, 50 }, { 58, 51 }, { 61, 46 }, { 58, 52 }, { 59, 51 }, { 59, 52 }, { 62, 47 }, { 59, 53 },
{ 60, 52 }, { 60, 53 }, { 60, 53 }, { 60, 54 }, { 61, 53 }, { 61, 54 }, { 61, 54 }, { 61, 55 },
{ 62, 54 }, { 62, 55 }, { 62, 55 }, { 62, 56 }, { 63, 55 }, { 63, 56 }, { 63, 56 }, { 63, 57 },
{ 63, 58 }, { 63, 59 }, { 63, 59 }, { 63, 60 }, { 63, 61 }, { 63, 62 }, { 63, 62 }, { 63, 63 },
{ 0, 0 }, { 0, 0 }, { 0, 0 }, { 1, 1 }, { 1, 1 }, { 1, 1 }, { 1, 1 }, { 2, 2 },
{ 2, 2 }, { 2, 2 }, { 2, 2 }, { 3, 3 }, { 3, 3 }, { 3, 3 }, { 3, 3 }, { 4, 4 },
{ 4, 4 }, { 4, 4 }, { 4, 4 }, { 5, 5 }, { 5, 5 }, { 5, 5 }, { 5, 5 }, { 6, 6 },
{ 6, 6 }, { 6, 6 }, { 6, 6 }, { 7, 7 }, { 7, 7 }, { 7, 7 }, { 7, 7 }, { 8, 8 },
{ 8, 8 }, { 8, 8 }, { 8, 8 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 9, 9 }, { 10, 10 },
{ 10, 10 }, { 10, 10 }, { 10, 10 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 11, 11 }, { 12, 12 },
{ 12, 12 }, { 12, 12 }, { 12, 12 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 13, 13 }, { 14, 14 },
{ 14, 14 }, { 14, 14 }, { 14, 14 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 15, 15 }, { 16, 16 },
{ 16, 16 }, { 16, 16 }, { 16, 16 }, { 16, 16 }, { 17, 17 }, { 17, 17 }, { 17, 17 }, { 17, 17 },
{ 18, 18 }, { 18, 18 }, { 18, 18 }, { 18, 18 }, { 19, 19 }, { 19, 19 }, { 19, 19 }, { 19, 19 },
{ 20, 20 }, { 20, 20 }, { 20, 20 }, { 20, 20 }, { 21, 21 }, { 21, 21 }, { 21, 21 }, { 21, 21 },
{ 22, 22 }, { 22, 22 }, { 22, 22 }, { 22, 22 }, { 23, 23 }, { 23, 23 }, { 23, 23 }, { 23, 23 },
{ 24, 24 }, { 24, 24 }, { 24, 24 }, { 24, 24 }, { 25, 25 }, { 25, 25 }, { 25, 25 }, { 25, 25 },
{ 26, 26 }, { 26, 26 }, { 26, 26 }, { 26, 26 }, { 27, 27 }, { 27, 27 }, { 27, 27 }, { 27, 27 },
{ 28, 28 }, { 28, 28 }, { 28, 28 }, { 28, 28 }, { 29, 29 }, { 29, 29 }, { 29, 29 }, { 29, 29 },
{ 30, 30 }, { 30, 30 }, { 30, 30 }, { 30, 30 }, { 31, 31 }, { 31, 31 }, { 31, 31 }, { 31, 31 },
{ 32, 32 }, { 32, 32 }, { 32, 32 }, { 32, 32 }, { 32, 32 }, { 33, 33 }, { 33, 33 }, { 33, 33 },
{ 33, 33 }, { 34, 34 }, { 34, 34 }, { 34, 34 }, { 34, 34 }, { 35, 35 }, { 35, 35 }, { 35, 35 },
{ 35, 35 }, { 36, 36 }, { 36, 36 }, { 36, 36 }, { 36, 36 }, { 37, 37 }, { 37, 37 }, { 37, 37 },
{ 37, 37 }, { 38, 38 }, { 38, 38 }, { 38, 38 }, { 38, 38 }, { 39, 39 }, { 39, 39 }, { 39, 39 },
{ 39, 39 }, { 40, 40 }, { 40, 40 }, { 40, 40 }, { 40, 40 }, { 41, 41 }, { 41, 41 }, { 41, 41 },
{ 41, 41 }, { 42, 42 }, { 42, 42 }, { 42, 42 }, { 42, 42 }, { 43, 43 }, { 43, 43 }, { 43, 43 },
{ 43, 43 }, { 44, 44 }, { 44, 44 }, { 44, 44 }, { 44, 44 }, { 45, 45 }, { 45, 45 }, { 45, 45 },
{ 45, 45 }, { 46, 46 }, { 46, 46 }, { 46, 46 }, { 46, 46 }, { 47, 47 }, { 47, 47 }, { 47, 47 },
{ 47, 47 }, { 48, 48 }, { 48, 48 }, { 48, 48 }, { 48, 48 }, { 48, 48 }, { 49, 49 }, { 49, 49 },
{ 49, 49 }, { 49, 49 }, { 50, 50 }, { 50, 50 }, { 50, 50 }, { 50, 50 }, { 51, 51 }, { 51, 51 },
{ 51, 51 }, { 51, 51 }, { 52, 52 }, { 52, 52 }, { 52, 52 }, { 52, 52 }, { 53, 53 }, { 53, 53 },
{ 53, 53 }, { 53, 53 }, { 54, 54 }, { 54, 54 }, { 54, 54 }, { 54, 54 }, { 55, 55 }, { 55, 55 },
{ 55, 55 }, { 55, 55 }, { 56, 56 }, { 56, 56 }, { 56, 56 }, { 56, 56 }, { 57, 57 }, { 57, 57 },
{ 57, 57 }, { 57, 57 }, { 58, 58 }, { 58, 58 }, { 58, 58 }, { 58, 58 }, { 59, 59 }, { 59, 59 },
{ 59, 59 }, { 59, 59 }, { 60, 60 }, { 60, 60 }, { 60, 60 }, { 60, 60 }, { 61, 61 }, { 61, 61 },
{ 61, 61 }, { 61, 61 }, { 62, 62 }, { 62, 62 }, { 62, 62 }, { 62, 62 }, { 63, 63 }, { 63, 63 },
};
static int stb__Mul8Bit(int a, int b)
@ -794,7 +794,7 @@ int main()
for (int j = 0; j < 256; ++j) {
int mn, mx;
int best_mn = 0, best_mx = 0;
int best_err = 256;
int best_err = 256 * 100;
for (mn=0;mn<size;mn++) {
for (mx=0;mx<size;mx++) {
int mine = (mn * dequant) >> 4;
@ -805,7 +805,7 @@ int main()
// add this as error term. Normally we'd expect a random distribution of
// +-1.5% error, but nowhere in the spec does it say that the error has to be
// unbiased - better safe than sorry.
err += abs(maxe - mine) * 3 / 100;
err += abs(maxe - mine) * 3;
if(err < best_err) {
best_mn = mn;