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Create libretro-common/include/filters.h

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This commit is contained in:
twinaphex 2015-09-12 21:04:20 +02:00
parent 80b3bc6254
commit 5adc85a207
3 changed files with 72 additions and 47 deletions
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35
audio/drivers_resampler/sinc.c
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@ -25,6 +25,7 @@
#endif
#include <retro_inline.h>
#include <filters.h>
#include <memalign.h>
#include "../audio_resampler_driver.h"
@ -116,43 +117,9 @@ typedef struct rarch_sinc_resampler
float *main_buffer;
} rarch_sinc_resampler_t;
static INLINE double sinc(double val)
{
if (fabs(val) < 0.00001)
return 1.0;
return sin(val) / val;
}
#if defined(SINC_WINDOW_LANCZOS)
#define window_function(idx) (sinc(M_PI * (idx)))
#elif defined(SINC_WINDOW_KAISER)
/* Modified Bessel function of first order.
* Check Wiki for mathematical definition ... */
static INLINE double besseli0(double x)
{
unsigned i;
double sum = 0.0;
double factorial = 1.0;
double factorial_mult = 0.0;
double x_pow = 1.0;
double two_div_pow = 1.0;
double x_sqr = x * x;
/* Approximate. This is an infinite sum.
* Luckily, it converges rather fast. */
for (i = 0; i < 18; i++)
{
sum += x_pow * two_div_pow / (factorial * factorial);
factorial_mult += 1.0;
x_pow *= x_sqr;
two_div_pow *= 0.25;
factorial *= factorial_mult;
}
return sum;
}
#define window_function(idx) (besseli0(SINC_WINDOW_KAISER_BETA * sqrt(1 - (idx) * (idx))))
#else
#error "No SINC window function defined."

21
libretro-common/gfx/scaler/scaler_filter.c
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@ -20,16 +20,19 @@
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <gfx/scaler/filter.h>
#include <gfx/scaler/scaler_int.h>
#include <retro_miscellaneous.h>
#include <math.h>
#include <retro_inline.h>
#include <filters.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#include <stdio.h>
#include <string.h>
#include <retro_inline.h>
static bool allocate_filters(struct scaler_ctx *ctx)
{
@ -113,13 +116,6 @@ static bool gen_filter_bilinear(struct scaler_ctx *ctx)
return true;
}
static INLINE double filter_sinc(double phase)
{
if (fabs(phase) < 0.0001)
return 1.0;
return sin(phase) / phase;
}
static void gen_filter_sinc_sub(struct scaler_filter *filter,
int len, int pos, int step, double phase_mul)
{
@ -134,7 +130,7 @@ static void gen_filter_sinc_sub(struct scaler_filter *filter,
{
double sinc_phase = M_PI * ((double)((sinc_size << 15) + (pos & 0xffff)) / 0x10000 - j);
double lanczos_phase = sinc_phase / ((sinc_size >> 1));
int16_t sinc_val = FILTER_UNITY * filter_sinc(sinc_phase * phase_mul) * filter_sinc(lanczos_phase) * phase_mul;
int16_t sinc_val = FILTER_UNITY * sinc(sinc_phase * phase_mul) * sinc(lanczos_phase) * phase_mul;
filter->filter[i * sinc_size + j] = sinc_val;
}
@ -172,7 +168,6 @@ static bool gen_filter_sinc(struct scaler_ctx *ctx)
return true;
}
static bool validate_filter(struct scaler_ctx *ctx)
{
int i;

63
libretro-common/include/filters.h Normal file
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@ -0,0 +1,63 @@
/* Copyright (C) 2010-2015 The RetroArch team
*
* ---------------------------------------------------------------------------------------
* The following license statement only applies to this file (filters.h).
* ---------------------------------------------------------------------------------------
*
* Permission is hereby granted, free of charge,
* to any person obtaining a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _LIBRETRO_SDK_FILTERS_H
#define _LIBRETRO_SDK_FILTERS_H
#include <math.h>
#include <retro_inline.h>
static INLINE double sinc(double val)
{
if (fabs(val) < 0.00001)
return 1.0;
return sin(val) / val;
}
/* Modified Bessel function of first order.
* Check Wiki for mathematical definition ... */
static INLINE double besseli0(double x)
{
unsigned i;
double sum = 0.0;
double factorial = 1.0;
double factorial_mult = 0.0;
double x_pow = 1.0;
double two_div_pow = 1.0;
double x_sqr = x * x;
/* Approximate. This is an infinite sum.
* Luckily, it converges rather fast. */
for (i = 0; i < 18; i++)
{
sum += x_pow * two_div_pow / (factorial * factorial);
factorial_mult += 1.0;
x_pow *= x_sqr;
two_div_pow *= 0.25;
factorial *= factorial_mult;
}
return sum;
}
#endif