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Allow SDL2 to change the audio frequency

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The mixer can handle arbitrary frequencies, so there's no point in
forcing SDL2 to use 44100Hz.
This commit is contained in:
Clownacy 2019-09-10 22:11:31 +00:00
parent 88f22510ee
commit 949bfd129b
1 changed files with 8 additions and 6 deletions
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14
src/Backends/Audio/SDL2.cpp
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@ -10,8 +10,6 @@
#include "../../Organya.h" #include "../../Organya.h"
#include "../../WindowsWrapper.h" #include "../../WindowsWrapper.h"
#define OUTPUT_FREQUENCY 44100
#define MIN(a, b) ((a) < (b) ? (a) : (b)) #define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b)) #define MAX(a, b) ((a) > (b) ? (a) : (b))
#define clamp(x, y, z) MIN(MAX((x), (y)), (z)) #define clamp(x, y, z) MIN(MAX((x), (y)), (z))
@ -37,6 +35,8 @@ struct AudioBackend_Sound
static AudioBackend_Sound *sound_list_head; static AudioBackend_Sound *sound_list_head;
static SDL_AudioDeviceID device_id; static SDL_AudioDeviceID device_id;
static unsigned long output_frequency;
static double MillibelToScale(long volume) static double MillibelToScale(long volume)
{ {
// Volume is in hundredths of decibels, from 0 to -10000 // Volume is in hundredths of decibels, from 0 to -10000
@ -47,7 +47,7 @@ static double MillibelToScale(long volume)
static void SetSoundFrequency(AudioBackend_Sound *sound, unsigned int frequency) static void SetSoundFrequency(AudioBackend_Sound *sound, unsigned int frequency)
{ {
sound->frequency = frequency; sound->frequency = frequency;
sound->advance_delta = (double)frequency / (double)OUTPUT_FREQUENCY; sound->advance_delta = (double)frequency / (double)output_frequency;
} }
static void SetSoundVolume(AudioBackend_Sound *sound, long volume) static void SetSoundVolume(AudioBackend_Sound *sound, long volume)
@ -150,7 +150,7 @@ static void Callback(void *user_data, Uint8 *stream_uint8, int len)
if (organya_countdown == 0) if (organya_countdown == 0)
{ {
organya_countdown = (organya_timer * OUTPUT_FREQUENCY) / 1000; // organya_timer is in milliseconds, so convert it to audio frames organya_countdown = (organya_timer * output_frequency) / 1000; // organya_timer is in milliseconds, so convert it to audio frames
UpdateOrganya(); UpdateOrganya();
} }
@ -170,14 +170,16 @@ BOOL AudioBackend_Init(void)
return FALSE; return FALSE;
SDL_AudioSpec specification; SDL_AudioSpec specification;
specification.freq = OUTPUT_FREQUENCY; specification.freq = 44100;
specification.format = AUDIO_F32; specification.format = AUDIO_F32;
specification.channels = 2; specification.channels = 2;
specification.samples = 0x400; // Roughly 10 milliseconds for 44100Hz specification.samples = 0x400; // Roughly 10 milliseconds for 44100Hz
specification.callback = Callback; specification.callback = Callback;
specification.userdata = NULL; specification.userdata = NULL;
device_id = SDL_OpenAudioDevice(NULL, 0, &specification, NULL, 0); SDL_AudioSpec obtained_specification;
device_id = SDL_OpenAudioDevice(NULL, 0, &specification, &obtained_specification, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
output_frequency = obtained_specification.freq;
if (device_id == 0) if (device_id == 0)
return FALSE; return FALSE;