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comparison src/audio/SDL_audiocvt.c @ 2728:2768bd7281e0

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Fixed Visual Studio compilation problems
author Sam Lantinga <slouken@libsdl.org>
date Tue, 26 Aug 2008 07:34:49 +0000
parents f8f68f47285a
children 79c1bd651f04
comparison
equal deleted inserted replaced
2727:76c2fc9696ea 2728:2768bd7281e0
18 18
19 Sam Lantinga 19 Sam Lantinga
20 slouken@libsdl.org 20 slouken@libsdl.org
21 */ 21 */
22 #include "SDL_config.h" 22 #include "SDL_config.h"
23
24 #define _USE_MATH_DEFINES
23 #include <math.h> 25 #include <math.h>
24 26
25 /* Functions for audio drivers to perform runtime conversion of audio format */ 27 /* Functions for audio drivers to perform runtime conversion of audio format */
26 28
27 #include "SDL_audio.h" 29 #include "SDL_audio.h"
28 #include "SDL_audio_c.h" 30 #include "SDL_audio_c.h"
29 31
30 #define DEBUG_CONVERT 32 //#define DEBUG_CONVERT
31 33
32 /* These are fractional multiplication routines. That is, their inputs 34 /* These are fractional multiplication routines. That is, their inputs
33 are two numbers in the range [-1, 1) and the result falls in that 35 are two numbers in the range [-1, 1) and the result falls in that
34 same range. The output is the same size as the inputs, i.e. 36 same range. The output is the same size as the inputs, i.e.
35 32-bit x 32-bit = 32-bit. 37 32-bit x 32-bit = 32-bit.
1367 cvt->len_div) ? CUTOFF / (float) cvt->len_mult : CUTOFF / 1369 cvt->len_div) ? CUTOFF / (float) cvt->len_mult : CUTOFF /
1368 (float) cvt->len_div; 1370 (float) cvt->len_div;
1369 1371
1370 w0 = 2.0f * M_PI * fc; 1372 w0 = 2.0f * M_PI * fc;
1371 cosw0 = cosf(w0); 1373 cosw0 = cosf(w0);
1372 alpha = sin(w0) / (2.0f * Q); 1374 alpha = sinf(w0) / (2.0f * Q);
1373 1375
1374 /* Compute coefficients, normalizing by a0 */ 1376 /* Compute coefficients, normalizing by a0 */
1375 scale = 1.0f / (1.0f + alpha); 1377 scale = 1.0f / (1.0f + alpha);
1376 1378
1377 coeff[0] = (1.0f - cosw0) / 2.0f * scale; 1379 coeff[0] = (1.0f - cosw0) / 2.0f * scale;
1436 } 1438 }
1437 #undef debug_iir 1439 #undef debug_iir
1438 #endif 1440 #endif
1439 1441
1440 /* Initialize the state buffer to all zeroes, and set initial position */ 1442 /* Initialize the state buffer to all zeroes, and set initial position */
1441 memset(cvt->state_buf, 0, 4 * SDL_AUDIO_BITSIZE(format) / 4); 1443 SDL_memset(cvt->state_buf, 0, 4 * SDL_AUDIO_BITSIZE(format) / 4);
1442 cvt->state_pos = 0; 1444 cvt->state_pos = 0;
1443 #undef convert_fixed 1445 #undef convert_fixed
1444 } 1446 }
1445 1447
1446 /* Apply the lowpass IIR filter to the given SDL_AudioCVT struct */ 1448 /* Apply the lowpass IIR filter to the given SDL_AudioCVT struct */
1634 1636
1635 /* Set the length */ 1637 /* Set the length */
1636 cvt->len_sinc = m + 1; 1638 cvt->len_sinc = m + 1;
1637 1639
1638 /* Allocate the floating point windowed sinc. */ 1640 /* Allocate the floating point windowed sinc. */
1639 fSinc = (float *) malloc((m + 1) * sizeof(float)); 1641 fSinc = SDL_stack_alloc(float, (m + 1));
1640 if (fSinc == NULL) { 1642 if (fSinc == NULL) {
1641 return -1; 1643 return -1;
1642 } 1644 }
1643 1645
1644 /* Set up the filter parameters */ 1646 /* Set up the filter parameters */
1697 break; 1699 break;
1698 } 1700 }
1699 } 1701 }
1700 1702
1701 /* Initialize the state buffer to all zeroes, and set initial position */ 1703 /* Initialize the state buffer to all zeroes, and set initial position */
1702 memset(cvt->state_buf, 0, cvt->len_sinc * SDL_AUDIO_BITSIZE(format) / 4); 1704 SDL_memset(cvt->state_buf, 0,
1705 cvt->len_sinc * SDL_AUDIO_BITSIZE(format) / 4);
1703 cvt->state_pos = 0; 1706 cvt->state_pos = 0;
1704 1707
1705 /* Clean up */ 1708 /* Clean up */
1706 #undef convert_fixed 1709 #undef convert_fixed
1707 free(fSinc); 1710 SDL_stack_free(fSinc);
1708 } 1711 }
1709 1712
1710 /* This is used to reduce the resampling ratio */ 1713 /* This is used to reduce the resampling ratio */
1711 inline int 1714 static __inline__ int
1712 SDL_GCD(int a, int b) 1715 SDL_GCD(int a, int b)
1713 { 1716 {
1714 int temp; 1717 int temp;
1715 while (b != 0) { 1718 while (b != 0) {
1716 temp = a % b; 1719 temp = a % b;