notaz.gp2x.de / pcsx_rearmed.git / blame
| Commit | Line | Data |
|---|---|---|
| 3719602c PC |
1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * | |
| 3 | * --------------------------------------------------------------------------------------- | |
| 4 | * The following license statement only applies to this file (filters.h). | |
| 5 | * --------------------------------------------------------------------------------------- | |
| 6 | * | |
| 7 | * Permission is hereby granted, free of charge, | |
| 8 | * to any person obtaining a copy of this software and associated documentation files (the "Software"), | |
| 9 | * to deal in the Software without restriction, including without limitation the rights to | |
| 10 | * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
| 11 | * and to permit persons to whom the Software is furnished to do so, subject to the following conditions: | |
| 12 | * | |
| 13 | * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. | |
| 14 | * | |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, | |
| 16 | * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. | |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, | |
| 19 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| 20 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
| 21 | */ | |
| 22 | ||
| 23 | #ifndef _LIBRETRO_SDK_FILTERS_H | |
| 24 | #define _LIBRETRO_SDK_FILTERS_H | |
| 25 | ||
| 26 | /* for MSVC; should be benign under any circumstances */ | |
| 27 | #define _USE_MATH_DEFINES | |
| 28 | ||
| 29 | #include <stdlib.h> | |
| 30 | #include <math.h> | |
| 31 | #include <retro_inline.h> | |
| 32 | #include <retro_math.h> | |
| 33 | ||
| 34 | /** | |
| 35 | * sinc: | |
| 36 | * | |
| 37 | * Pure function. | |
| 38 | **/ | |
| 39 | static INLINE double sinc(double val) | |
| 40 | { | |
| 41 | if (fabs(val) < 0.00001) | |
| 42 | return 1.0; | |
| 43 | return sin(val) / val; | |
| 44 | } | |
| 45 | ||
| 46 | /** | |
| 47 | * paeth: | |
| 48 | * | |
| 49 | * Pure function. | |
| 50 | * Paeth prediction filter. | |
| 51 | **/ | |
| 52 | static INLINE int paeth(int a, int b, int c) | |
| 53 | { | |
| 54 | int p = a + b - c; | |
| 55 | int pa = abs(p - a); | |
| 56 | int pb = abs(p - b); | |
| 57 | int pc = abs(p - c); | |
| 58 | ||
| 59 | if (pa <= pb && pa <= pc) | |
| 60 | return a; | |
| 61 | else if (pb <= pc) | |
| 62 | return b; | |
| 63 | return c; | |
| 64 | } | |
| 65 | ||
| 66 | /** | |
| 67 | * besseli0: | |
| 68 | * | |
| 69 | * Pure function. | |
| 70 | * | |
| 71 | * Modified Bessel function of first order. | |
| 72 | * Check Wiki for mathematical definition ... | |
| 73 | **/ | |
| 74 | static INLINE double besseli0(double x) | |
| 75 | { | |
| 76 | int i; | |
| 77 | double sum = 0.0; | |
| 78 | double factorial = 1.0; | |
| 79 | double factorial_mult = 0.0; | |
| 80 | double x_pow = 1.0; | |
| 81 | double two_div_pow = 1.0; | |
| 82 | double x_sqr = x * x; | |
| 83 | ||
| 84 | /* Approximate. This is an infinite sum. | |
| 85 | * Luckily, it converges rather fast. */ | |
| 86 | for (i = 0; i < 18; i++) | |
| 87 | { | |
| 88 | sum += x_pow * two_div_pow / (factorial * factorial); | |
| 89 | factorial_mult += 1.0; | |
| 90 | x_pow *= x_sqr; | |
| 91 | two_div_pow *= 0.25; | |
| 92 | factorial *= factorial_mult; | |
| 93 | } | |
| 94 | ||
| 95 | return sum; | |
| 96 | } | |
| 97 | ||
| 98 | static INLINE double kaiser_window_function(double index, double beta) | |
| 99 | { | |
| 100 | return besseli0(beta * sqrtf(1 - index * index)); | |
| 101 | } | |
| 102 | ||
| 103 | #endif |