Java tutorial
/******************************************************************************* * Copyright 2011 See AUTHORS file. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. ******************************************************************************/ package com.badlogic.gdx.backends.lwjgl.audio; import java.nio.ByteBuffer; import java.nio.IntBuffer; import org.lwjgl.BufferUtils; import org.lwjgl.openal.AL11; import com.badlogic.gdx.audio.Music; import com.badlogic.gdx.files.FileHandle; import com.badlogic.gdx.math.MathUtils; import com.badlogic.gdx.utils.GdxRuntimeException; import static org.lwjgl.openal.AL10.*; /** @author Nathan Sweet */ public abstract class OpenALMusic implements Music { static private final int bufferSize = 4096 * 10; static private final int bufferCount = 3; static private final int bytesPerSample = 2; static private final byte[] tempBytes = new byte[bufferSize]; static private final ByteBuffer tempBuffer = BufferUtils.createByteBuffer(bufferSize); private final OpenALAudio audio; private IntBuffer buffers; private int sourceID = -1; private int format, sampleRate; private boolean isLooping, isPlaying; private float volume = 1; private float pan = 0; private float renderedSeconds, secondsPerBuffer; protected final FileHandle file; private OnCompletionListener onCompletionListener; public OpenALMusic(OpenALAudio audio, FileHandle file) { this.audio = audio; this.file = file; this.onCompletionListener = null; } protected void setup(int channels, int sampleRate) { this.format = channels > 1 ? AL_FORMAT_STEREO16 : AL_FORMAT_MONO16; this.sampleRate = sampleRate; secondsPerBuffer = (float) bufferSize / bytesPerSample / channels / sampleRate; } public void play() { if (audio.noDevice) return; if (sourceID == -1) { sourceID = audio.obtainSource(true); if (sourceID == -1) return; audio.music.add(this); if (buffers == null) { buffers = BufferUtils.createIntBuffer(bufferCount); alGenBuffers(buffers); if (alGetError() != AL_NO_ERROR) throw new GdxRuntimeException("Unable to allocate audio buffers."); } alSourcei(sourceID, AL_LOOPING, AL_FALSE); setPan(pan, volume); boolean filled = false; // Check if there's anything to actually play. for (int i = 0; i < bufferCount; i++) { int bufferID = buffers.get(i); if (!fill(bufferID)) break; filled = true; alSourceQueueBuffers(sourceID, bufferID); } if (!filled && onCompletionListener != null) onCompletionListener.onCompletion(this); if (alGetError() != AL_NO_ERROR) { stop(); return; } } if (!isPlaying) { alSourcePlay(sourceID); isPlaying = true; } } public void stop() { if (audio.noDevice) return; if (sourceID == -1) return; audio.music.removeValue(this, true); reset(); audio.freeSource(sourceID); sourceID = -1; renderedSeconds = 0; isPlaying = false; } public void pause() { if (audio.noDevice) return; if (sourceID != -1) alSourcePause(sourceID); isPlaying = false; } public boolean isPlaying() { if (audio.noDevice) return false; if (sourceID == -1) return false; return isPlaying; } public void setLooping(boolean isLooping) { this.isLooping = isLooping; } public boolean isLooping() { return isLooping; } public void setVolume(float volume) { this.volume = volume; if (audio.noDevice) return; if (sourceID != -1) alSourcef(sourceID, AL_GAIN, volume); } public float getVolume() { return this.volume; } public void setPan(float pan, float volume) { this.volume = volume; this.pan = pan; if (audio.noDevice) return; if (sourceID == -1) return; alSource3f(sourceID, AL_POSITION, MathUtils.cos((pan - 1) * MathUtils.PI / 2), 0, MathUtils.sin((pan + 1) * MathUtils.PI / 2)); alSourcef(sourceID, AL_GAIN, volume); } public void setPosition(float position) { if (audio.noDevice) return; if (sourceID == -1) return; boolean wasPlaying = isPlaying; isPlaying = false; alSourceStop(sourceID); renderedSeconds += secondsPerBuffer; if (position <= renderedSeconds) { reset(); renderedSeconds = 0; } while (renderedSeconds < (position - secondsPerBuffer)) { if (read(tempBytes) <= 0) break; renderedSeconds += secondsPerBuffer; } update(); alSourcef(sourceID, AL11.AL_SEC_OFFSET, position - renderedSeconds); if (wasPlaying) { alSourcePlay(sourceID); isPlaying = true; } } public float getPosition() { if (audio.noDevice) return 0; if (sourceID == -1) return 0; return renderedSeconds + alGetSourcef(sourceID, AL11.AL_SEC_OFFSET); } /** Fills as much of the buffer as possible and returns the number of bytes filled. Returns <= 0 to indicate the end of the * stream. */ abstract public int read(byte[] buffer); /** Resets the stream to the beginning. */ abstract public void reset(); /** By default, does just the same as reset(). Used to add special behaviour in Ogg.Music. */ protected void loop() { reset(); } public int getChannels() { return format == AL_FORMAT_STEREO16 ? 2 : 1; } public int getRate() { return sampleRate; } public void update() { if (audio.noDevice) return; if (sourceID == -1) return; boolean end = false; int buffers = alGetSourcei(sourceID, AL_BUFFERS_PROCESSED); while (buffers-- > 0) { int bufferID = alSourceUnqueueBuffers(sourceID); if (bufferID == AL_INVALID_VALUE) break; renderedSeconds += secondsPerBuffer; if (end) continue; if (fill(bufferID)) alSourceQueueBuffers(sourceID, bufferID); else end = true; } if (end && alGetSourcei(sourceID, AL_BUFFERS_QUEUED) == 0) { stop(); if (onCompletionListener != null) onCompletionListener.onCompletion(this); } // A buffer underflow will cause the source to stop. if (isPlaying && alGetSourcei(sourceID, AL_SOURCE_STATE) != AL_PLAYING) alSourcePlay(sourceID); } private boolean fill(int bufferID) { tempBuffer.clear(); int length = read(tempBytes); if (length <= 0) { if (isLooping) { loop(); renderedSeconds = 0; length = read(tempBytes); if (length <= 0) return false; } else return false; } tempBuffer.put(tempBytes, 0, length).flip(); alBufferData(bufferID, format, tempBuffer, sampleRate); return true; } public void dispose() { stop(); if (audio.noDevice) return; if (buffers == null) return; alDeleteBuffers(buffers); buffers = null; onCompletionListener = null; } public void setOnCompletionListener(OnCompletionListener listener) { onCompletionListener = listener; } public int getSourceId() { return sourceID; } }