63 lines
1.0 KiB
C
63 lines
1.0 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <SDL2/SDL.h>
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#include <unistd.h>
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static uint8_t buf[1024];
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static int wp=256, rp=0;
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static int soundEna=0;
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static int bufLen() {
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return (wp-rp)&1023;
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}
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int sndDone() {
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if (!soundEna) return 0;
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return (bufLen()<512);
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}
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int sndPush(uint8_t *data, int volume) {
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if (!soundEna) return 0;
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while(!sndDone()) usleep(1000);
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for (int i=0; i<370; i++) {
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int s=*data;
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s=(s-128)>>(7-volume);
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buf[wp++]=s+128;
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if (wp==1024) wp=0;
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data+=2;
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}
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return 1;
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}
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static void sndCb(void* userdata, Uint8* stream, int len) {
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for (int i=0; i<len; i++) {
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stream[i]=buf[rp++];
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if (rp==1024) rp=0;
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}
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}
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void sndInit() {
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SDL_AudioSpec want, have;
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SDL_AudioDeviceID dev;
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SDL_memset(&want, 0, sizeof(want));
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want.freq = 22000;
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want.format = AUDIO_U8;
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want.channels = 1;
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want.samples = 256;
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want.callback = sndCb;
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dev = SDL_OpenAudioDevice(NULL, 0, &want, &have, 0);
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if (dev == 0) {
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SDL_Log("Failed to open audio: %s", SDL_GetError());
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} else {
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SDL_PauseAudioDevice(dev, 0);
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soundEna=1;
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}
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}
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