| 1 | /* SDL Driver for P.E.Op.S Sound Plugin |
| 2 | * Copyright (c) 2010, Wei Mingzhi <whistler_wmz@users.sf.net>. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1307 USA |
| 17 | */ |
| 18 | |
| 19 | #include <stdlib.h> |
| 20 | #include <SDL.h> |
| 21 | #include "out.h" |
| 22 | |
| 23 | #define BUFFER_SIZE 22050 |
| 24 | |
| 25 | short *pSndBuffer = NULL; |
| 26 | int iBufSize = 0; |
| 27 | volatile int iReadPos = 0, iWritePos = 0; |
| 28 | |
| 29 | static void SOUND_FillAudio(void *unused, Uint8 *stream, int len) { |
| 30 | short *p = (short *)stream; |
| 31 | |
| 32 | len /= sizeof(short); |
| 33 | |
| 34 | while (iReadPos != iWritePos && len > 0) { |
| 35 | *p++ = pSndBuffer[iReadPos++]; |
| 36 | if (iReadPos >= iBufSize) iReadPos = 0; |
| 37 | --len; |
| 38 | } |
| 39 | |
| 40 | // Fill remaining space with zero |
| 41 | while (len > 0) { |
| 42 | *p++ = 0; |
| 43 | --len; |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | static void InitSDL() { |
| 48 | if (SDL_WasInit(SDL_INIT_EVERYTHING)) { |
| 49 | SDL_InitSubSystem(SDL_INIT_AUDIO); |
| 50 | } else { |
| 51 | SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE); |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | static void DestroySDL() { |
| 56 | if (SDL_WasInit(SDL_INIT_EVERYTHING & ~SDL_INIT_AUDIO)) { |
| 57 | SDL_QuitSubSystem(SDL_INIT_AUDIO); |
| 58 | } else { |
| 59 | SDL_Quit(); |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | static int sdl_init(void) { |
| 64 | SDL_AudioSpec spec; |
| 65 | |
| 66 | if (pSndBuffer != NULL) return -1; |
| 67 | |
| 68 | InitSDL(); |
| 69 | |
| 70 | spec.freq = 44100; |
| 71 | spec.format = AUDIO_S16SYS; |
| 72 | spec.channels = 2; |
| 73 | spec.samples = 512; |
| 74 | spec.callback = SOUND_FillAudio; |
| 75 | |
| 76 | if (SDL_OpenAudio(&spec, NULL) < 0) { |
| 77 | DestroySDL(); |
| 78 | return -1; |
| 79 | } |
| 80 | |
| 81 | iBufSize = BUFFER_SIZE; |
| 82 | |
| 83 | pSndBuffer = (short *)malloc(iBufSize * sizeof(short)); |
| 84 | if (pSndBuffer == NULL) { |
| 85 | SDL_CloseAudio(); |
| 86 | return -1; |
| 87 | } |
| 88 | |
| 89 | iReadPos = 0; |
| 90 | iWritePos = 0; |
| 91 | |
| 92 | SDL_PauseAudio(0); |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | static void sdl_finish(void) { |
| 97 | if (pSndBuffer == NULL) return; |
| 98 | |
| 99 | SDL_CloseAudio(); |
| 100 | DestroySDL(); |
| 101 | |
| 102 | free(pSndBuffer); |
| 103 | pSndBuffer = NULL; |
| 104 | } |
| 105 | |
| 106 | static int sdl_busy(void) { |
| 107 | int size; |
| 108 | |
| 109 | if (pSndBuffer == NULL) return 1; |
| 110 | |
| 111 | size = iReadPos - iWritePos; |
| 112 | if (size <= 0) size += iBufSize; |
| 113 | |
| 114 | if (size < iBufSize / 2) return 1; |
| 115 | |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | static void sdl_feed(void *pSound, int lBytes) { |
| 120 | short *p = (short *)pSound; |
| 121 | |
| 122 | if (pSndBuffer == NULL) return; |
| 123 | |
| 124 | while (lBytes > 0) { |
| 125 | if (((iWritePos + 1) % iBufSize) == iReadPos) break; |
| 126 | |
| 127 | pSndBuffer[iWritePos] = *p++; |
| 128 | |
| 129 | ++iWritePos; |
| 130 | if (iWritePos >= iBufSize) iWritePos = 0; |
| 131 | |
| 132 | lBytes -= sizeof(short); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | void out_register_sdl(struct out_driver *drv) |
| 137 | { |
| 138 | drv->name = "sdl"; |
| 139 | drv->init = sdl_init; |
| 140 | drv->finish = sdl_finish; |
| 141 | drv->busy = sdl_busy; |
| 142 | drv->feed = sdl_feed; |
| 143 | } |