Chiptune Sound Library: SFXR

This is a fork of the NES-style sound effect generator made by Dr Petterr. There's a similar webapp version of Dr Petter's sound maker. If you would like to preview what types of sounds this library will make! I have redesigned it to be a C library rather than a standalone application. So you can use it to create new sound effects as needed in your game!

I included comments wherever i figured something out and tried to make it a lot clearer than the original; and included helper functions to set sound frequency based on midi key!

Example of saving a file:

// the library never calls malloc, there is no memory management everything is stack based. 
sfxr_Settings settings;
sfxr_Coin(&settings)
sfxr_ExportWAV(&settings, /* bit rate */ 16, /* sample rate */ 44100, "coin.wav");

Example of creating a new sound with FMOD using C++:

If you want to use unity then combine this example with this page here

FMOD::Sound * CreateSound(FMOD::System * system, sfxr_Settings const& settings)
{
	FMOD::Sound * sound = nullptr;
// the model is data used during sound generation that never changes, it can be used for multiple generators
// you're free to change the settings once you have the model
	sfxr_Model model;
	sfxr_ModelInit(&model, settings);
// the data is stuff that does change during sound generation, it can't be used among multiple instances
// it maintains a reference to the model, so the model can't be deleted until all the data is also.
	sfxr_Data  data;
	sfxr_DataInit(&data, &model);
	
	std::vector<float> _samples;
// compute size of buffer we need 
	_samples.resize(sfxr_ComputeRemainingSamples(&data));
	
// synth as float samples, this doesn't have to be all at once, the data is like an iterator in the sample!
	sfxr_DataSynthSample(&data, _samples.size(), _samples.data());
	
// done with this library now we use FMOD!!
	
// we don't really need to create the whole buffer to make an FMOD sound but thats the easiest way to do it.
// it would be smarter to make a buffer about 1/2 a second long, or 20k samples and fill the lower half 
// when we're in the upper half and vice versa

// this creates an empty FMOD sound with no data!!!
	FMOD_CREATESOUNDEXINFO info;
	memset(&info, 0, sizeof(info));
	info.cbsize = sizeof(info);
	info.length = _samples.size() * sizeof(_samples[0]);
	info.numchannels = 1;
	info.defaultfrequency = 44100;
	
// humans can't actually hear a difference between float and short data (limit of hearing is 12 bits so 16 is already padded)
	info.format = FMOD_SOUND_FORMAT_PCMFLOAT;  
	
	system->createSound(
		nullptr,
		FMOD_OPENUSER,
		&info,
		&sound);
	
	if(sound == nullptr) return nullptr;

// now we actually copy the samples we generated into FMOD
// because we're doing this all at once we had to pre-generate the buffer
// (because otherwise we don't know how big the buffer needs to be!
	void * ptr1, * ptr2;
	uint32_t len1, len2;
	size_t offset = 0;
	
	while(offset < _samples.size())
	{
		sound->lock(offset, (_samples.size()-offset) * 4, &ptr1, &ptr2, &len1, &len2);
	
		assert(len1%4 == 0);
		assert(len2%4 == 0);
	
		memcpy(ptr1, &_samples[offset], len1); offset += len1 / 4;
		memcpy(ptr2, &_samples[offset], len2); offset += len2 / 4;
		sound->unlock(ptr1, ptr2, len1, len2);
	}
	
	return sound;
}