private void AddInstance(SoundInstance soundInstance, int polyphony)
{
if (soundInstance.sound.data.Length == 0)
{
return;
}
SoundInstanceInternal instance = new SoundInstanceInternal(soundInstance);
if (!dataInstanceCount.ContainsKey(instance.sound))
{
dataInstanceCount.Add(instance.sound, 0);
}
lock (audibleSounds)
instance.offsetStart = GetBufferOffset();
instance.position = soundInstance.startPosition;
EnforcePolyphony(polyphony, instance, instance.offsetStart);
lock (audibleSounds)
{
audibleSounds.Add(instance);
dataInstanceCount[instance.sound] = dataInstanceCount[instance.sound] + 1;
}
}
public void PlayScheduled(double position, SoundInstance soundInstance, int polyphony)
{
if (soundInstance.sound.data.Length == 0)
{
return;
}
SoundInstanceInternal instance = new SoundInstanceInternal(soundInstance);
if (!dataInstanceCount.ContainsKey(instance.sound))
{
dataInstanceCount.Add(instance.sound, 0);
}
double bufferPosition = (position - lastCallback) * ((double)audioSpec.freq);
uint offset = (uint)(bufferPosition * bytesPerSample);
if (offset % 4 != 0)
{
offset += 4 - (offset % 4);
}
instance.offsetStart = offset;
instance.position = soundInstance.startPosition;
EnforcePolyphony(polyphony, instance, offset);
lock (audibleSounds)
{
audibleSounds.Add(instance);
dataInstanceCount[instance.sound] = dataInstanceCount[instance.sound] + 1;
}
}
public byte[] RenderAudio()
{
if (audioDriver != AudioDriver.File)
{
return(null);
}
uint streamLength = 0;
for (int i = 0; i < audibleSounds.Count; ++i)
{
SoundInstanceInternal instance = audibleSounds[i];
if (streamLength < instance.offsetStart + instance.endPosition)
{
streamLength = instance.offsetStart + instance.endPosition;
}
}
if (streamLength == 0)
{
return(null);
}
byte[] bytes = new byte[(int)streamLength];
GCHandle stream = GCHandle.Alloc(bytes, GCHandleType.Pinned);
for (int i = 0; i < audibleSounds.Count; ++i)
{
SoundInstanceInternal instance = audibleSounds[i];
int playLength = (int)(instance.offsetStop - instance.offsetStart);
if (playLength > instance.endPosition)
{
playLength = (int)instance.endPosition;
}
else if (playLength <= 0)
{
playLength = (int)instance.endPosition;
}
IntPtr streamOffset = stream.AddrOfPinnedObject();
streamOffset += (int)instance.offsetStart;
byte finalVolume = (byte)Math.Round(Math.Min(volume * instance.volume * SDL.SDL_MIX_MAXVOLUME, SDL.SDL_MIX_MAXVOLUME));
SDL_MixAudioFormat(streamOffset, instance.sound.data, audioSpec.format, (uint)playLength, finalVolume);
}
stream.Free();
audibleSounds.Clear();
return(bytes);
}
private void EnforcePolyphony(int polyphony, SoundInstanceInternal instance, uint offset)
{
if (polyphony == 0)
{
return;
}
SoundData sound = instance.sound;
if (dataInstanceCount[sound] < polyphony)
{
return;
}
int removeCount = dataInstanceCount[sound] - polyphony + 1;
lock (audibleSounds)
{
for (int i = 0; i < audibleSounds.Count; ++i)
{
SoundInstanceInternal audibleInstance = audibleSounds[i];
if (audibleInstance.sound != sound)
{
continue;
}
if (audibleInstance.remove)
{
continue;
}
// only apply polyphony to identical slices
if (audibleInstance.instance.startPosition != instance.instance.startPosition ||
audibleInstance.instance.endPosition != instance.instance.endPosition)
{
continue;
}
// mark instance for later removal
audibleInstance.paused = true;
audibleInstance.remove = true;
audibleInstance.offsetStop = offset;
removeCount--;
if (removeCount <= 0)
{
break;
}
}
}
}
private void CopySample(SoundInstanceInternal instance, IntPtr userData, IntPtr stream, int length)
{
uint sampleLeft = Math.Min(instance.endPosition - instance.position, (uint)length);
uint startOffset = instance.offsetStart;
uint pauseOffset = instance.offsetStop;
if (startOffset < length)
{
uint copyLength = Math.Min(sampleLeft + startOffset, (uint)length) - startOffset;
if (instance.paused)
{
if (startOffset <= pauseOffset)
{
copyLength = Math.Min(pauseOffset - startOffset, copyLength);
}
else
{
copyLength = 0;
}
instance.offsetStop = 0;
}
// audio clip starts playing at starting offset
Array.Copy(instance.sound.data, instance.position, audioBuffer, startOffset, copyLength);
instance.position += copyLength;
instance.offsetStart = 0;
}
else
{
instance.offsetStart -= (uint)length;
}
if (instance.position >= instance.endPosition)
{
instance.remove = true;
}
}
private void MixAudio(IntPtr userData, IntPtr stream, int length)
{
for (int i = 0; i < audibleSounds.Count; ++i)
{
SoundInstanceInternal instance = audibleSounds[i];
// fill temporary buffer with silence
Array.Copy(emptyBuffer, 0, audioBuffer, 0, length);
CopySample(instance, userData, stream, length);
byte finalVolume = (byte)Math.Round(Math.Min(volume * instance.volume * SDL.SDL_MIX_MAXVOLUME, SDL.SDL_MIX_MAXVOLUME));
SDL_MixAudioFormat(stream, audioBuffer, audioSpec.format, (uint)length, finalVolume);
if (instance.remove)
{
audibleSounds.RemoveAt(i);
dataInstanceCount[instance.sound] = dataInstanceCount[instance.sound] - 1;
i--;
}
}
}
