Mercurial > sdl-ios-xcode
changeset 1537:60620d71e324
Corrected dummy audio callback firing to be realistic, cleaned up tabs.
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Tue, 14 Mar 2006 19:12:49 +0000 |
| parents | 5151662ab728 |
| children | b1f8c14f0df5 |
| files | src/audio/dummy/SDL_dummyaudio.c src/audio/dummy/SDL_dummyaudio.h |
| diffstat | 2 files changed, 24 insertions(+), 11 deletions(-) [+] |
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--- a/src/audio/dummy/SDL_dummyaudio.c Tue Mar 14 17:33:33 2006 +0000 +++ b/src/audio/dummy/SDL_dummyaudio.c Tue Mar 14 19:12:49 2006 +0000 @@ -19,8 +19,7 @@ Sam Lantinga slouken@libsdl.org - This file hacked^H^H^H^H^H^Hwritten by Ryan C. Gordon - (icculus@icculus.org) + This file written by Ryan C. Gordon (icculus@icculus.org) */ #include "SDL_config.h" @@ -37,10 +36,6 @@ /* The tag name used by DUMMY audio */ #define DUMMYAUD_DRIVER_NAME "dummy" -/* environment variables and defaults. */ -#define DUMMYENVR_WRITEDELAY "SDL_DUMMYAUDIODELAY" -#define DUMMYDEFAULT_WRITEDELAY 150 - /* Audio driver functions */ static int DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec *spec); static void DUMMYAUD_WaitAudio(_THIS); @@ -85,9 +80,6 @@ } SDL_memset(this->hidden, 0, (sizeof *this->hidden)); - envr = SDL_getenv(DUMMYENVR_WRITEDELAY); - this->hidden->write_delay = (envr) ? SDL_atoi(envr) : DUMMYDEFAULT_WRITEDELAY; - /* Set the function pointers */ this->OpenAudio = DUMMYAUD_OpenAudio; this->WaitAudio = DUMMYAUD_WaitAudio; @@ -108,12 +100,16 @@ /* This function waits until it is possible to write a full sound buffer */ static void DUMMYAUD_WaitAudio(_THIS) { - SDL_Delay(this->hidden->write_delay); + /* Don't block on first calls to simulate initial fragment filling. */ + if (this->hidden->initial_calls) + this->hidden->initial_calls--; + else + SDL_Delay(this->hidden->write_delay); } static void DUMMYAUD_PlayAudio(_THIS) { - /* no-op...this is a null driver. */ + /* no-op...this is a null driver. */ } static Uint8 *DUMMYAUD_GetAudioBuf(_THIS) @@ -131,6 +127,8 @@ static int DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec *spec) { + float bytes_per_sec = 0.0f; + /* Allocate mixing buffer */ this->hidden->mixlen = spec->size; this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen); @@ -139,6 +137,20 @@ } SDL_memset(this->hidden->mixbuf, spec->silence, spec->size); + bytes_per_sec = (float) (((spec->format & 0xFF) / 8) * + spec->channels * spec->freq); + + /* + * We try to make this request more audio at the correct rate for + * a given audio spec, so timing stays fairly faithful. + * Also, we have it not block at all for the first two calls, so + * it seems like we're filling two audio fragments right out of the + * gate, like other SDL drivers tend to do. + */ + this->hidden->initial_calls = 2; + this->hidden->write_delay = + (Uint32) ((((float) spec->size) / bytes_per_sec) * 1000.0f); + /* We're ready to rock and roll. :-) */ return(0); }