Dengine/src/Audio.c

#include <OpenAL/alc.h>

#define STB_VORBIS_HEADER_ONLY
#include <STB/stb_vorbis.c>

#include "Dengine/Assets.h"
#include "Dengine/Audio.h"
#include "Dengine/Common.h"
#include "Dengine/Debug.h"

#define AL_CHECK_ERROR() alCheckError_(__FILE__, __LINE__);
void alCheckError_(const char *file, int line)
{

	ALenum errorCode;
	while ((errorCode = alGetError()) != AL_NO_ERROR)
	{
		printf("OPENAL ");
		switch(errorCode)
		{
		case AL_INVALID_NAME:
			printf("INVALID_NAME | ");
			break;
		case AL_INVALID_ENUM:
			printf("INVALID_ENUM | ");
			break;
		case AL_INVALID_VALUE:
			printf("INVALID_VALUE | ");
			break;
		case AL_INVALID_OPERATION:
			printf("INVALID_OPERATION | ");
			break;
		case AL_OUT_OF_MEMORY:
			printf("OUT_OF_MEMORY | ");
			break;
		default:
			printf("UNRECOGNISED ERROR CODE | ");
			break;
		}
		printf("Error %08x, %s (%d)\n", errorCode, file, line);
	}
};

const i32 audio_rendererInit(AudioRenderer *audioRenderer)
{
	alGetError();
	ALCdevice *deviceAL = alcOpenDevice(NULL);
	if (!deviceAL)
	{
		printf("alcOpenDevice() failed: Failed to init OpenAL device.\n");
		return -1;
	}

	ALCcontext *contextAL = alcCreateContext(deviceAL, NULL);
	alcMakeContextCurrent(contextAL);
	if (!contextAL)
	{
		printf("alcCreateContext() failed: Failed create AL context.\n");
		return -1;
	}
	AL_CHECK_ERROR();

	/* Generate number of concurrent audio file listeners */
	alGenSources(ARRAY_COUNT(audioRenderer->sourceId), audioRenderer->sourceId);
	AL_CHECK_ERROR();

	/* Generate audio data buffers */
	alGenBuffers(ARRAY_COUNT(audioRenderer->bufferId), audioRenderer->bufferId);
	AL_CHECK_ERROR();

	return 0;
}

#define AUDIO_CHUNK_SIZE_ 65536
void audio_streamVorbis(AudioRenderer *audioRenderer, AudioVorbis *vorbis)
{
	/* Determine format */
	audioRenderer->format = AL_FORMAT_MONO16;
	if (vorbis->info.channels == 2)
		audioRenderer->format = AL_FORMAT_STEREO16;
	else if (vorbis->info.channels != 1)
		DEBUG_LOG("audio_streamVorbis() warning: Unaccounted channel format");

	audioRenderer->audio = vorbis;
	AudioVorbis *audio   = audioRenderer->audio;

	/* Pre-load vorbis data into audio chunks */
	for (i32 i = 0; i < ARRAY_COUNT(audioRenderer->bufferId); i++)
	{
		i16 audioChunk[AUDIO_CHUNK_SIZE_] = {0};
		stb_vorbis_get_samples_short_interleaved(
		    audio->file, audio->info.channels, audioChunk, AUDIO_CHUNK_SIZE_);

		alBufferData(audioRenderer->bufferId[i], audioRenderer->format,
		             audioChunk, AUDIO_CHUNK_SIZE_ * sizeof(i16),
		             audio->info.sample_rate);
	}

	/* Queue and play buffers */
	alSourceQueueBuffers(audioRenderer->sourceId[0],
	                     ARRAY_COUNT(audioRenderer->bufferId),
	                     audioRenderer->bufferId);
	alSourcePlay(audioRenderer->sourceId[0]);
}

void audio_updateAndPlay(AudioRenderer *audioRenderer)
{
	AudioVorbis *audio = audioRenderer->audio;

	ALint audioState;
	alGetSourcei(audioRenderer->sourceId[0], AL_SOURCE_STATE, &audioState);
	if (audioState == AL_STOPPED || audioState == AL_INITIAL)
	{
		// TODO(doyle): This fixes clicking when reusing old buffers
		if (audioState == AL_STOPPED)
		{
			alDeleteBuffers(ARRAY_COUNT(audioRenderer->bufferId),
			                audioRenderer->bufferId);
			alGenBuffers(ARRAY_COUNT(audioRenderer->bufferId),
			             audioRenderer->bufferId);
		}

		stb_vorbis_seek_start(audio->file);
		for (i32 i = 0; i < ARRAY_COUNT(audioRenderer->bufferId); i++)
		{
			i16 audioChunk[AUDIO_CHUNK_SIZE_] = {0};
			stb_vorbis_get_samples_short_interleaved(
			    audio->file, audio->info.channels, audioChunk,
			    AUDIO_CHUNK_SIZE_);

			alBufferData(audioRenderer->bufferId[i], audioRenderer->format,
			             audioChunk, AUDIO_CHUNK_SIZE_ * sizeof(i16),
			             audio->info.sample_rate);
		}

		alSourceQueueBuffers(audioRenderer->sourceId[0],
		                     ARRAY_COUNT(audioRenderer->bufferId),
		                     audioRenderer->bufferId);
		alSourcePlay(audioRenderer->sourceId[0]);
	}
	else if (audioState == AL_PLAYING)
	{
		ALint numProcessedBuffers;
		alGetSourcei(audioRenderer->sourceId[0], AL_BUFFERS_PROCESSED,
		             &numProcessedBuffers);
		if (numProcessedBuffers > 0)
		{
			ALint numBuffersToUnqueue = 1;
			ALuint emptyBufferId;
			alSourceUnqueueBuffers(audioRenderer->sourceId[0],
			                       numBuffersToUnqueue, &emptyBufferId);

			i16 audioChunk[AUDIO_CHUNK_SIZE_] = {0};
			i32 sampleCount = stb_vorbis_get_samples_short_interleaved(
			    audio->file, audio->info.channels, audioChunk,
			    AUDIO_CHUNK_SIZE_);

			/* There are still samples to play */
			if (sampleCount > 0)
			{
				DEBUG_LOG("Buffering new audio data");
				alBufferData(emptyBufferId, audioRenderer->format, audioChunk,
				             sampleCount * audio->info.channels * sizeof(i16),
				             audio->info.sample_rate);
				alSourceQueueBuffers(audioRenderer->sourceId[0], 1,
				                     &emptyBufferId);
			}
		}
	}
}