108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
// ampler.c
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <SDL2/SDL.h>
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#define SAMPLE_RATE (44100)
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#define CHANNELS (2)
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#define FRAME_SAMPLES (SAMPLE_RATE / 60)
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typedef uint8_t s8;
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typedef uint16_t s16;
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typedef struct Ampler_state Ampler_state;
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struct Ampler_state {
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int size;
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SDL_AudioDeviceID playdev;
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s8 track_l[SAMPLE_RATE * 120]; // 2 minutes
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s8 track_r[SAMPLE_RATE * 120]; // 2 minutes
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};
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int audio_frame(Ampler_state *state) {
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int queued = SDL_GetQueuedAudioSize(state -> playdev);
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queued /= sizeof s16; // queued is in bytes
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if(queued > FRAME_SAMPLES * CHANNELS * 2) return 0;
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// else puts("queued audio.");
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s16 silence[FRAME_SAMPLES * CHANNELS] = { 0 };
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for (int i = 0; i < FRAME_SAMPLES; i += CHANNELS) {
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int vol = 10;
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silence[i] = (i/2) * vol - FRAME_SAMPLES / 2;
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silence[i + 1] = (i/2) * vol - FRAME_SAMPLES / 2;
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}
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if(SDL_QueueAudio(state -> playdev, silence, sizeof silence))
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puts(SDL_GetError());
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return 1; // audio was qued
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}
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Ampler_state *init() {
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Ampler_state *state = malloc(sizeof Ampler_state);
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SDL_memset(state, 0, sizeof Ampler_state);
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state -> size = sizeof Ampler_state;
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SDL_AudioSpec want = { 0 }, have = { 0 };
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want.freq = SAMPLE_RATE;
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want.format = AUDIO_S16;
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want.channels = CHANNELS;
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want.samples = 512;
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want.callback = NULL; // use que funcs
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want.userdata = NULL;
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state -> playdev = SDL_OpenAudioDevice(
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NULL, // default device
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0, // not capture
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&want,
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&have,
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0 // no changes allowed
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);
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if(!(state -> playdev))
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puts(SDL_GetError());
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puts("init.");
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return state;
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}
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int ampler_main(SDL_Window *w, SDL_Renderer *r, Ampler_state **u_data) {
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if(*u_data == NULL) *u_data = init();
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int old_size = (*u_data) -> size, new_size = sizeof Ampler_state;
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if(old_size < new_size) {
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printf("increasing size. %i to %i\n", old_size, new_size);
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Ampler_state *nu = malloc(new_size);
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SDL_memset(nu, 0, new_size);
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SDL_memcpy(nu, *u_data, old_size);
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nu -> size = new_size;
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free(*u_data);
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*u_data = nu;
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}
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Ampler_state *state = *u_data;
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SDL_PauseAudioDevice(state -> playdev, 0); // unpause audio
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while (1) {
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SDL_Event e;
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while(SDL_PollEvent(&e))
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if (e.type == SDL_QUIT)
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return 1;
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audio_frame(state);
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// draw_frame(w, r, state);
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SDL_RenderPresent(r);
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SDL_Delay(1);
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if (!remove("reload-trigger")) {
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SDL_PauseAudioDevice(state -> playdev, 1); // pause audio
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puts("removed reload-trigger, reloading...");
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return 0;
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}
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}
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}
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