1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
#include "../minisdl_audio.h"
#define TSF_IMPLEMENTATION
#include "../tsf.h"
// Holds the global instance pointer
static tsf* g_TinySoundFont;
// A Mutex so we don't call note_on/note_off while rendering audio samples
static SDL_mutex* g_Mutex;
static void AudioCallback(void* data, Uint8 *stream, int len) {
// Render the audio samples in float format
int SampleCount = (len / (2 * sizeof(float))); //2 output channels
SDL_LockMutex(g_Mutex); //get exclusive lock
tsf_render_float(g_TinySoundFont, (float*)stream, SampleCount, 0);
SDL_UnlockMutex(g_Mutex);
}
int main(int argc, char *argv[]) {
int i, Notes[7] = { 48, 50, 52, 53, 55, 57, 59 };
// Define the desired audio output format we request
SDL_AudioSpec OutputAudioSpec;
OutputAudioSpec.freq = 44100;
OutputAudioSpec.format = AUDIO_F32;
OutputAudioSpec.channels = 2;
OutputAudioSpec.samples = 4096;
OutputAudioSpec.callback = AudioCallback;
// Initialize the audio system
if (SDL_AudioInit(TSF_NULL) < 0) {
fprintf(stderr, "Could not initialize audio hardware or driver\n");
return 1;
}
// Load the SoundFont from a file
g_TinySoundFont = tsf_load_filename("../sf2/florestan-subset.sf2");
if (!g_TinySoundFont) {
fprintf(stderr, "Could not load SoundFont\n");
return 1;
}
// Set the SoundFont rendering output mode
tsf_set_output(g_TinySoundFont, TSF_STEREO_INTERLEAVED, OutputAudioSpec.freq, 0);
// Create the mutex
g_Mutex = SDL_CreateMutex();
// Request the desired audio output format
if (SDL_OpenAudio(&OutputAudioSpec, TSF_NULL) < 0) {
fprintf(stderr, "Could not open the audio hardware or the desired audio output format\n");
return 1;
}
// Start the actual audio playback here
// The audio thread will begin to call our AudioCallback function
SDL_PauseAudio(0);
// Loop through all the presets in the loaded SoundFont
for (i = 0; i < tsf_get_presetcount(g_TinySoundFont); i++) {
//Get exclusive mutex lock, end the previous note and play a new note
printf("Play note %d with preset #%d '%s'\n", Notes[i % 7], i, tsf_get_presetname(g_TinySoundFont, i));
SDL_LockMutex(g_Mutex);
tsf_note_off(g_TinySoundFont, i - 1, Notes[(i - 1) % 7]);
tsf_note_on(g_TinySoundFont, i, Notes[i % 7], 1.0f);
SDL_UnlockMutex(g_Mutex);
SDL_Delay(1000);
}
// We could call tsf_close(g_TinySoundFont) and SDL_DestroyMutex(g_Mutex)
// here to free the memory and resources but we just let the OS clean up
// because the process ends here.
return 0;
}
|
