113 lines
2.3 KiB
C
113 lines
2.3 KiB
C
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#include <stdio.h>
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#include "SDL_audio.h"
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#include "SDL_byteorder.h"
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#include "quakedef.h"
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static dma_t the_shm;
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static int snd_inited;
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extern int desired_speed;
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extern int desired_bits;
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static void paint_audio(void *unused, Uint8 *stream, int len)
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{
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if ( shm ) {
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shm->buffer = stream;
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shm->samplepos += len/(shm->samplebits/8)/2;
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// Check for samplepos overflow?
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S_PaintChannels (shm->samplepos);
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}
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}
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qboolean SNDDMA_Init(void)
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{
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SDL_AudioSpec desired, obtained;
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snd_inited = 0;
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/* Set up the desired format */
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desired.freq = desired_speed;
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switch (desired_bits) {
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case 8:
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desired.format = AUDIO_U8;
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break;
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case 16:
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if ( SDL_BYTEORDER == SDL_BIG_ENDIAN )
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desired.format = AUDIO_S16MSB;
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else
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desired.format = AUDIO_S16LSB;
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break;
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default:
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Con_Printf("Unknown number of audio bits: %d\n",
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desired_bits);
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return 0;
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}
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desired.channels = 2;
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desired.samples = 512;
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desired.callback = paint_audio;
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/* Open the audio device */
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if ( SDL_OpenAudio(&desired, &obtained) < 0 ) {
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Con_Printf("Couldn't open SDL audio: %s\n", SDL_GetError());
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return 0;
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}
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/* Make sure we can support the audio format */
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switch (obtained.format) {
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case AUDIO_U8:
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/* Supported */
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break;
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case AUDIO_S16LSB:
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case AUDIO_S16MSB:
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if ( ((obtained.format == AUDIO_S16LSB) &&
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(SDL_BYTEORDER == SDL_LIL_ENDIAN)) ||
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((obtained.format == AUDIO_S16MSB) &&
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(SDL_BYTEORDER == SDL_BIG_ENDIAN)) ) {
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/* Supported */
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break;
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}
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/* Unsupported, fall through */;
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default:
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/* Not supported -- force SDL to do our bidding */
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SDL_CloseAudio();
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if ( SDL_OpenAudio(&desired, NULL) < 0 ) {
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Con_Printf("Couldn't open SDL audio: %s\n",
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SDL_GetError());
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return 0;
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}
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memcpy(&obtained, &desired, sizeof(desired));
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break;
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}
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SDL_PauseAudio(0);
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/* Fill the audio DMA information block */
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shm = &the_shm;
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shm->splitbuffer = 0;
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shm->samplebits = (obtained.format & 0xFF);
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shm->speed = obtained.freq;
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shm->channels = obtained.channels;
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shm->samples = obtained.samples*shm->channels;
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shm->samplepos = 0;
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shm->submission_chunk = 1;
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shm->buffer = NULL;
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snd_inited = 1;
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return 1;
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}
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int SNDDMA_GetDMAPos(void)
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{
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return shm->samplepos;
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}
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void SNDDMA_Shutdown(void)
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{
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if (snd_inited)
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{
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SDL_CloseAudio();
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snd_inited = 0;
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}
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}
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