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better numerical precision for playback example

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expikr
2025-01-14 00:58:06 +08:00
committed by Sam Lantinga
parent e5a4f09363
commit 569de84907
2 changed files with 8 additions and 10 deletions
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9
examples/audio/01-simple-playback/simple-playback.c
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@@ -73,12 +73,11 @@ SDL_AppResult SDL_AppIterate(void *appstate)
static float samples[512]; /* this will feed 512 samples each frame until we get to our maximum. */
int i;
/* generate a 440Hz pure tone */
for (i = 0; i < SDL_arraysize(samples); i++) {
/* You don't have to care about this math; we're just generating a simple sine wave as we go.
https://en.wikipedia.org/wiki/Sine_wave */
const double time = total_samples_generated / 8000.0;
const int sine_freq = 500; /* run the wave at 500Hz */
samples[i] = (float)SDL_sin(6.283185 * sine_freq * time);
const int freq = 440;
const int phase = (total_samples_generated * freq) % 8000;
samples[i] = (float)SDL_sin(phase * 2 * SDL_PI_D / 8000.0);
total_samples_generated++;
}

9
examples/audio/02-simple-playback-callback/simple-playback-callback.c
View File

@@ -33,12 +33,11 @@ static void SDLCALL FeedTheAudioStreamMore(void *userdata, SDL_AudioStream *astr
const int total = SDL_min(additional_amount, SDL_arraysize(samples));
int i;
/* generate a 440Hz pure tone */
for (i = 0; i < total; i++) {
/* You don't have to care about this math; we're just generating a simple sine wave as we go.
https://en.wikipedia.org/wiki/Sine_wave */
const double time = total_samples_generated / 8000.0;
const int sine_freq = 500; /* run the wave at 500Hz */
samples[i] = (float)SDL_sin(6.283185 * sine_freq * time);
const int freq = 440;
const int phase = (total_samples_generated * freq) % 8000;
samples[i] = (float)SDL_sin(phase * 2 * SDL_PI_D / 8000.0);
total_samples_generated++;
}