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