Mercurial > hg > forks > pwpunix
annotate pwplib/snd-sdl.c @ 43:093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
| author | Matti Hamalainen <ccr@tnsp.org> |
|---|---|
| date | Mon, 24 May 2010 05:07:33 +0300 |
| parents | b9d679965320 |
| children | 85671798fdb3 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * pwplib SDL (Simple Directmedia Layer) audio "driver" | |
| 3 * (C) Copyright 2010 ccr/TNSP^PWP <ccr@tnsp.org> | |
| 4 * | |
| 5 * This file and other changes are distributed under same | |
| 6 * license as pwplib itself. | |
| 7 */ | |
| 8 | |
| 9 #include "config.h" | |
| 10 | |
| 11 #ifdef DRIVE_SDL | |
| 12 | |
| 13 #include <stdio.h> | |
| 14 #include <stdlib.h> | |
| 15 #include <unistd.h> | |
| 16 #include <SDL.h> | |
| 17 | |
| 18 #include "pwplib.h" | |
| 35 | 19 #include "gb.h" |
| 0 | 20 |
|
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Fix a horrible think-o bug in the SDL sound callback fragmentation code.
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21 #define TIMERHZ 72 |
| 0 | 22 |
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Take into account that SDL does not guarantee audio buffer size to be what
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23 static int pwp_sdlaudio_run = 1; |
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24 static int pwp_sdlaudio_frag = -1, pwp_sdlaudio_curr; |
| 0 | 25 |
| 26 | |
|
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Some misc. cleanups and minor warning removals.
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27 static void pwp_sdlaudio_fill(void * udata, Uint8 * buf, int len) |
| 0 | 28 { |
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29 (void) udata; |
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30 while (len > 0) { |
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31 if (pwp_sdlaudio_curr >= len) { |
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32 pwp_sdlaudio_curr -= len; |
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33 gb_genwave(buf, len); |
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34 len = 0; |
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35 } else { |
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36 gb_genwave(buf, pwp_sdlaudio_curr); |
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37 buf += pwp_sdlaudio_curr; |
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38 len -= pwp_sdlaudio_curr; |
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39 pwp_sdlaudio_curr = pwp_sdlaudio_frag; |
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40 pwplib.player(); |
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41 } |
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42 } |
| 0 | 43 } |
| 44 | |
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45 static void pwp_sdlaudio_start(void) |
| 0 | 46 { |
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47 if (pwp_sdlaudio_run) { |
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a379d6a2a717
Take into account that SDL does not guarantee audio buffer size to be what
Matti Hamalainen <ccr@tnsp.org>
parents:
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diff
changeset
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48 pwp_sdlaudio_curr = pwp_sdlaudio_frag; |
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a379d6a2a717
Take into account that SDL does not guarantee audio buffer size to be what
Matti Hamalainen <ccr@tnsp.org>
parents:
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diff
changeset
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49 pwp_sdlaudio_run = 0; |
|
34
32ec3c0d1b6c
Fix a horrible think-o bug in the SDL sound callback fragmentation code.
Matti Hamalainen <ccr@tnsp.org>
parents:
31
diff
changeset
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50 pwplib.player(); |
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Possibly start SDL audio more sanely.
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51 SDL_PauseAudio(0); |
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52 } |
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43
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
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53 |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
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54 /* NOTICE! A small delay is used here, because the prods using pwplib |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
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55 * run in a tight loop (they expect that audio rendering blocks, |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
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56 * which it doesn't in case of SDL.) This way we avoid consuming |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
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57 * excessive amounts of CPU. |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
|
58 * |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
|
59 * -- ccr |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
|
60 */ |
|
093315d84a22
Add a small delay in SDL audio pseudo-loopflush function to avoid tightlooping in prod main loops (explained better in the added comment.)
Matti Hamalainen <ccr@tnsp.org>
parents:
35
diff
changeset
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61 SDL_Delay(10); |
| 0 | 62 } |
| 63 | |
| 64 int pwp_sdlaudio_init() | |
| 65 { | |
| 66 SDL_AudioSpec fmt; | |
| 67 | |
|
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a379d6a2a717
Take into account that SDL does not guarantee audio buffer size to be what
Matti Hamalainen <ccr@tnsp.org>
parents:
6
diff
changeset
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68 pwp_sdlaudio_run = 1; |
|
a379d6a2a717
Take into account that SDL does not guarantee audio buffer size to be what
Matti Hamalainen <ccr@tnsp.org>
parents:
6
diff
changeset
|
69 |
| 0 | 70 fmt.freq = 44100; |
| 71 fmt.format = AUDIO_U8; | |
| 72 fmt.channels = 1; | |
|
34
32ec3c0d1b6c
Fix a horrible think-o bug in the SDL sound callback fragmentation code.
Matti Hamalainen <ccr@tnsp.org>
parents:
31
diff
changeset
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73 fmt.samples = 512; |
| 0 | 74 fmt.callback = pwp_sdlaudio_fill; |
| 75 | |
| 76 if (SDL_OpenAudio(&fmt, NULL) < 0) | |
| 77 { | |
| 78 pwpwrite("* SDL: Could not get desired audio format.\n"); | |
| 79 return 0; | |
| 80 } | |
| 81 | |
|
31
502d54fd46fa
Remove useless pwp_sdlaudio_close(), move fragment size calculation after SDL_OpenAudio() call as it may possibly modify the frequency. Show acquired audio parameters to user.
Matti Hamalainen <ccr@tnsp.org>
parents:
18
diff
changeset
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82 pwp_sdlaudio_frag = fmt.freq / TIMERHZ; |
|
502d54fd46fa
Remove useless pwp_sdlaudio_close(), move fragment size calculation after SDL_OpenAudio() call as it may possibly modify the frequency. Show acquired audio parameters to user.
Matti Hamalainen <ccr@tnsp.org>
parents:
18
diff
changeset
|
83 |
|
502d54fd46fa
Remove useless pwp_sdlaudio_close(), move fragment size calculation after SDL_OpenAudio() call as it may possibly modify the frequency. Show acquired audio parameters to user.
Matti Hamalainen <ccr@tnsp.org>
parents:
18
diff
changeset
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84 pwpwrite("* SDL sound (freq=%d, fmt=%d, chn=%d, buf=%d, frag=%d)\n", |
|
502d54fd46fa
Remove useless pwp_sdlaudio_close(), move fragment size calculation after SDL_OpenAudio() call as it may possibly modify the frequency. Show acquired audio parameters to user.
Matti Hamalainen <ccr@tnsp.org>
parents:
18
diff
changeset
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85 fmt.freq, fmt.format, fmt.channels, fmt.samples, pwp_sdlaudio_frag); |
| 0 | 86 |
| 87 pwplib.sound = gb_sound; | |
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a379d6a2a717
Take into account that SDL does not guarantee audio buffer size to be what
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88 pwplib.loopflush = pwp_sdlaudio_start; |
| 0 | 89 gb_init(fmt.freq); |
| 90 | |
| 91 return 1; | |
| 92 } | |
| 93 #endif |