Tracker module playback using PortAudio and DUMB.

audio.c

#include <stdio.h>
#include <math.h>
#include <assert.h>
#include <stdbool.h>
#include <portaudio.h>
#include "dumb.h"
#include "audio.h"

#define BUFFERSIZE (2048L)
#define SAMPLE_RATE (44100)

static PaStream* stream = NULL;
static DUH_SIGRENDERER* renderer = NULL;

static enum {STATE_PAUSED, STATE_PLAYING} player_state;

// just a test
int temp_userdata = 42;

void die(const char* str)
{
	fprintf(stderr, "%s\n", str);
	exit(1);
}

void pa_error(PaError err)
{
	Pa_Terminate();
	fprintf( stderr, "An error occured while using the portaudio stream\n" );
	fprintf( stderr, "Error number: %d\n", err );
	fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
	die("Fatal error");
}

static int audioCallback( const void *inputBuffer, void *outputBuffer,
		unsigned long framesPerBuffer,
		const PaStreamCallbackTimeInfo* timeInfo,
		PaStreamCallbackFlags statusFlags,
		void *userData )
{
	signed short* out = (signed short*)outputBuffer;

	// fill the buffer with silence if no renderer has been created yet
	if (!renderer || (player_state == STATE_PAUSED)) {
		for (int i=0;i<BUFFERSIZE*2;i++) {
			out[i] = 0;
		}

		return paContinue;
	}

 	long result = duh_render(renderer, 16, 0, 1.0, 65536.0f/SAMPLE_RATE, BUFFERSIZE, out);

	//PlaybackInfo* info = (PlaybackInfo*)userData;
	return paContinue;
}

bool init_portaudio()
{

	PaError err;
	PaStreamParameters outputParameters;

	err = Pa_Initialize();
	if (err!=paNoError) return true;
	printf("Using portaudio v%d\n", Pa_GetVersion());

	int samplesize = Pa_GetSampleSize(paInt16);
	assert(samplesize == 2); // we like 16-bit audio

	outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */

	if (outputParameters.device == paNoDevice) {
		die("Error: No default output device.");
	}

	outputParameters.channelCount = 2; /* stereo output */
	outputParameters.sampleFormat = paInt16; /* 16 bit signed integer output */
	outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency;
	outputParameters.hostApiSpecificStreamInfo = NULL;

	err = Pa_OpenStream(
			&stream,
			NULL, /* no input */
			&outputParameters,
			(double)SAMPLE_RATE,
			BUFFERSIZE,
			0, 
			audioCallback,
			&temp_userdata);

	if (err != paNoError) pa_error(err);

	return false;
}

void audio_init()
{
	player_state = STATE_PAUSED;

	PaError err;
	puts("dumb init");
	dumb_register_stdfiles();

	puts("portaudio init");
	if (init_portaudio()) 
		die("Couldn't initialize portaudio!!");

	err = Pa_StartStream(stream);
	if (err != paNoError) pa_error(err);

	player_state = STATE_PLAYING;
}

void audio_close()
{
	PaError err;
	err = Pa_StopStream(stream);
	if (err != paNoError) pa_error(err);

	duh_end_sigrenderer(renderer);
	renderer = NULL;
	dumb_exit();
	
	err = Pa_CloseStream(stream);
	if (err != paNoError) pa_error(err);

	Pa_Terminate();
}

void audio_play_song(DUH* song)
{
	if (renderer)
		duh_end_sigrenderer(renderer);

	renderer = duh_start_sigrenderer(song, 0, 2, 0);
}

void audio_pause_song(DUH* song)
{
	player_state = STATE_PAUSED;
}

void audio_continue_song(DUH* song)
{
	player_state = STATE_PLAYING;
}

audio.h

#pragma once

#include "dumb.h"

void audio_init();
void audio_close();
void audio_play_song(DUH* song);
void audio_pause_song(DUH* song);
void audio_continue_song(DUH* song);