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comparison src/audio/dummy/SDL_dummyaudio.c @ 2049:5f6550e5184f

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Merged SDL-ryan-multiple-audio-device branch r2803:2871 into the trunk.
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 17 Oct 2006 09:15:21 +0000
parents c121d94672cb
children 866052b01ee5
comparison
equal deleted inserted replaced
2048:6067c7f9a672 2049:5f6550e5184f
23 */ 23 */
24 #include "SDL_config.h" 24 #include "SDL_config.h"
25 25
26 /* Output audio to nowhere... */ 26 /* Output audio to nowhere... */
27 27
28 #include "SDL_rwops.h"
29 #include "SDL_timer.h"
30 #include "SDL_audio.h" 28 #include "SDL_audio.h"
31 #include "../SDL_audiomem.h"
32 #include "../SDL_audio_c.h" 29 #include "../SDL_audio_c.h"
33 #include "../SDL_audiodev_c.h"
34 #include "SDL_dummyaudio.h" 30 #include "SDL_dummyaudio.h"
35 31
36 /* The tag name used by DUMMY audio */
37 #define DUMMYAUD_DRIVER_NAME "dummy"
38
39 /* Audio driver functions */
40 static int DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec * spec);
41 static void DUMMYAUD_WaitAudio(_THIS);
42 static void DUMMYAUD_PlayAudio(_THIS);
43 static Uint8 *DUMMYAUD_GetAudioBuf(_THIS);
44 static void DUMMYAUD_CloseAudio(_THIS);
45
46 /* Audio driver bootstrap functions */
47 static int 32 static int
48 DUMMYAUD_Available(void) 33 DUMMYAUD_OpenDevice(_THIS, const char *devname, int iscapture)
49 { 34 {
50 const char *envr = SDL_getenv("SDL_AUDIODRIVER"); 35 return 1; /* always succeeds. */
51 if (envr && (SDL_strcmp(envr, DUMMYAUD_DRIVER_NAME) == 0)) {
52 return (1);
53 }
54 return (0);
55 } 36 }
56 37
57 static void 38 static int
58 DUMMYAUD_DeleteDevice(SDL_AudioDevice * device) 39 DUMMYAUD_Init(SDL_AudioDriverImpl *impl)
59 { 40 {
60 SDL_free(device->hidden);
61 SDL_free(device);
62 }
63
64 static SDL_AudioDevice *
65 DUMMYAUD_CreateDevice(int devindex)
66 {
67 SDL_AudioDevice *this;
68
69 /* Initialize all variables that we clean on shutdown */
70 this = (SDL_AudioDevice *) SDL_malloc(sizeof(SDL_AudioDevice));
71 if (this) {
72 SDL_memset(this, 0, (sizeof *this));
73 this->hidden = (struct SDL_PrivateAudioData *)
74 SDL_malloc((sizeof *this->hidden));
75 }
76 if ((this == NULL) || (this->hidden == NULL)) {
77 SDL_OutOfMemory();
78 if (this) {
79 SDL_free(this);
80 }
81 return (0);
82 }
83 SDL_memset(this->hidden, 0, (sizeof *this->hidden));
84
85 /* Set the function pointers */ 41 /* Set the function pointers */
86 this->OpenAudio = DUMMYAUD_OpenAudio; 42 impl->OpenDevice = DUMMYAUD_OpenDevice;
87 this->WaitAudio = DUMMYAUD_WaitAudio; 43 impl->OnlyHasDefaultOutputDevice = 1;
88 this->PlayAudio = DUMMYAUD_PlayAudio; 44 return 1;
89 this->GetAudioBuf = DUMMYAUD_GetAudioBuf;
90 this->CloseAudio = DUMMYAUD_CloseAudio;
91
92 this->free = DUMMYAUD_DeleteDevice;
93
94 return this;
95 } 45 }
96 46
97 AudioBootStrap DUMMYAUD_bootstrap = { 47 AudioBootStrap DUMMYAUD_bootstrap = {
98 DUMMYAUD_DRIVER_NAME, "SDL dummy audio driver", 48 "dummy", "SDL dummy audio driver", DUMMYAUD_Init, 1
99 DUMMYAUD_Available, DUMMYAUD_CreateDevice
100 }; 49 };
101 50
102 /* This function waits until it is possible to write a full sound buffer */
103 static void
104 DUMMYAUD_WaitAudio(_THIS)
105 {
106 /* Don't block on first calls to simulate initial fragment filling. */
107 if (this->hidden->initial_calls)
108 this->hidden->initial_calls--;
109 else
110 SDL_Delay(this->hidden->write_delay);
111 }
112
113 static void
114 DUMMYAUD_PlayAudio(_THIS)
115 {
116 /* no-op...this is a null driver. */
117 }
118
119 static Uint8 *
120 DUMMYAUD_GetAudioBuf(_THIS)
121 {
122 return (this->hidden->mixbuf);
123 }
124
125 static void
126 DUMMYAUD_CloseAudio(_THIS)
127 {
128 if (this->hidden->mixbuf != NULL) {
129 SDL_FreeAudioMem(this->hidden->mixbuf);
130 this->hidden->mixbuf = NULL;
131 }
132 }
133
134 static int
135 DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec * spec)
136 {
137 float bytes_per_sec = 0.0f;
138
139 /* Allocate mixing buffer */
140 this->hidden->mixlen = spec->size;
141 this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
142 if (this->hidden->mixbuf == NULL) {
143 return (-1);
144 }
145 SDL_memset(this->hidden->mixbuf, spec->silence, spec->size);
146
147 bytes_per_sec = (float) (((spec->format & 0xFF) / 8) *
148 spec->channels * spec->freq);
149
150 /*
151 * We try to make this request more audio at the correct rate for
152 * a given audio spec, so timing stays fairly faithful.
153 * Also, we have it not block at all for the first two calls, so
154 * it seems like we're filling two audio fragments right out of the
155 * gate, like other SDL drivers tend to do.
156 */
157 this->hidden->initial_calls = 2;
158 this->hidden->write_delay =
159 (Uint32) ((((float) spec->size) / bytes_per_sec) * 1000.0f);
160
161 /* We're ready to rock and roll. :-) */
162 return (0);
163 }
164
165 /* vi: set ts=4 sw=4 expandtab: */ 51 /* vi: set ts=4 sw=4 expandtab: */