Method LoadFromFile

extensions/olcPGEX_Sound.h:233–315

	}

	olc::rcode SOUND::AudioSample::LoadFromFile(std::string sWavFile, olc::ResourcePack *pack)
	{
		auto ReadWave = [&](std::istream &is)
		{
			char dump[4];
			is.read(dump, sizeof(char) * 4); // Read "RIFF"
			if (strncmp(dump, "RIFF", 4) != 0) return olc::FAIL;
			is.read(dump, sizeof(char) * 4); // Not Interested
			is.read(dump, sizeof(char) * 4); // Read "WAVE"
			if (strncmp(dump, "WAVE", 4) != 0) return olc::FAIL;

			// Read Wave description chunk
			is.read(dump, sizeof(char) * 4); // Read "fmt "
			unsigned int nHeaderSize = 0;
			is.read((char*)&nHeaderSize, sizeof(unsigned int)); // Not Interested
			is.read((char*)&wavHeader, nHeaderSize);// sizeof(WAVEFORMATEX)); // Read Wave Format Structure chunk
														// Note the -2, because the structure has 2 bytes to indicate its own size
														// which are not in the wav file

			// Just check if wave format is compatible with olcPGE
			if (wavHeader.wBitsPerSample != 16 || wavHeader.nSamplesPerSec != 44100)
				return olc::FAIL;

			// Search for audio data chunk
			uint32_t nChunksize = 0;
			is.read(dump, sizeof(char) * 4); // Read chunk header
			is.read((char*)&nChunksize, sizeof(uint32_t)); // Read chunk size
			while (strncmp(dump, "data", 4) != 0)
			{
				// Not audio data, so just skip it
				//std::fseek(f, nChunksize, SEEK_CUR);
				is.seekg(nChunksize, std::istream::cur);
				is.read(dump, sizeof(char) * 4);
				is.read((char*)&nChunksize, sizeof(uint32_t));
			}

			// Finally got to data, so read it all in and convert to float samples
			nSamples = nChunksize / (wavHeader.nChannels * (wavHeader.wBitsPerSample >> 3));
			nChannels = wavHeader.nChannels;

			// Create floating point buffer to hold audio sample
			fSample = new float[nSamples * nChannels];
			float *pSample = fSample;

			// Read in audio data and normalise
			for (long i = 0; i < nSamples; i++)
			{
				for (int c = 0; c < nChannels; c++)
				{
					short s = 0;
					if (!is.eof())
					{
						is.read((char*)&s, sizeof(short));

						*pSample = (float)s / (float)(SHRT_MAX);
						pSample++;
					}
				}