- made the sound channel list part of the backend

Since the OpenAL backend heavily interacted with the list this is now moved out of the frontend code with an improved abstraction layer to ensure that the backend does not need to access frontend data directly

src/CMakeLists.txt

@@ -1227,6 +1227,7 @@ set (PCH_SOURCES
 	sound/music/i_music.cpp
 	sound/music/i_soundfont.cpp
 	sound/backend/i_sound.cpp
+	sound/backend/i_channellist.cpp
 	sound/mididevices/music_adlmidi_mididevice.cpp
 	sound/mididevices/music_opldumper_mididevice.cpp
 	sound/mididevices/music_opl_mididevice.cpp

src/sound/backend/i_channellist.cpp

@@ -0,0 +1,346 @@
+//-----------------------------------------------------------------------------
+//
+// Copyright 1993-1996 id Software
+// Copyright 1999-2016 Randy Heit
+// Copyright 2002-2016 Christoph Oelckers
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see http://www.gnu.org/licenses/
+//
+//-----------------------------------------------------------------------------
+//
+// DESCRIPTION:  Sound channel list
+//
+//-----------------------------------------------------------------------------
+
+
+#include <assert.h>
+#include "i_sound.h"
+#include "i_channellist.h"
+
+
+//==========================================================================
+//
+// S_GetChannel
+//
+// Returns a free channel for the system sound interface.
+//
+//==========================================================================
+
+FISoundChannel *FIChannelList::GetChannel(void *syschan)
+{
+	FISoundChannel *chan;
+
+	if (FreeChannels != nullptr)
+	{
+		chan = FreeChannels;
+		UnlinkChannel(chan);
+		return chan;
+	}
+	else
+	{
+		chan = (FISoundChannel *)malloc(ChannelStructSize);
+	}
+	memset(chan, 0, ChannelStructSize);
+	LinkChannel(chan, &Channels);
+	chan->SysChannel = syschan;
+	return chan;
+}
+
+//==========================================================================
+//
+// S_ReturnChannel
+//
+// Returns a channel to the free pool.
+//
+//==========================================================================
+
+void FIChannelList::ReturnChannel(FISoundChannel *chan)
+{
+	UnlinkChannel(chan);
+	LinkChannel(chan, &FreeChannels);
+}
+
+//==========================================================================
+//
+// S_UnlinkChannel
+//
+//==========================================================================
+
+void FIChannelList::UnlinkChannel(FISoundChannel *chan)
+{
+	*(chan->PrevChan) = chan->NextChan;
+	if (chan->NextChan != nullptr)
+	{
+		chan->NextChan->PrevChan = chan->PrevChan;
+	}
+}
+
+//==========================================================================
+//
+// S_LinkChannel
+//
+//==========================================================================
+
+void FIChannelList::LinkChannel(FISoundChannel *chan, FISoundChannel **head)
+{
+	chan->NextChan = *head;
+	if (chan->NextChan != nullptr)
+	{
+		chan->NextChan->PrevChan = &chan->NextChan;
+	}
+	*head = chan;
+	chan->PrevChan = head;
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+void FIChannelList::ReturnAllChannels()
+{
+	while (Channels != nullptr)
+	{
+		ReturnChannel(Channels);
+	}
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+void FIChannelList::StopAllChannels()
+{
+	auto chan = Channels;
+	while (chan != nullptr)
+	{
+		auto next = chan->NextChan;
+		StopChannel(chan);
+		chan = next;
+	}
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+void FIChannelList::FreeChannelList()
+{
+	// This should only be called when all sounds have been stopped.
+	assert(Channels == nullptr);
+	for(auto p = FreeChannels; p; p = p->NextChan)
+	{
+		free(p);
+	}
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+void FIChannelList::SetPitch(FISoundChannel *chan, float pitch)
+{
+	GSnd->ChannelPitch(chan, std::max(0.0001f, pitch));
+	chan->Pitch = std::max(1, int(float(NORM_PITCH) * pitch));
+}
+
+
+//==========================================================================
+//
+// S_ChannelEnded (callback for sound interface code)
+//
+//==========================================================================
+
+void FIChannelList::ChannelEnded(FISoundChannel *schan)
+{
+	bool evicted;
+
+	if (schan != NULL)
+	{
+		// If the sound was stopped with GSnd->StopSound(), then we know
+		// it wasn't evicted. Otherwise, if it's looping, it must have
+		// been evicted. If it's not looping, then it was evicted if it
+		// didn't reach the end of its playback.
+		if (schan->ChanFlags & CHAN_FORGETTABLE)
+		{
+			evicted = false;
+		}
+		else if (schan->ChanFlags & (CHAN_LOOP | CHAN_EVICTED))
+		{
+			evicted = true;
+		}
+		else
+		{
+			unsigned int pos = GSnd->GetPosition(schan);
+			unsigned int len = GSnd->GetSampleLength(SoundData(schan));
+			if (pos == 0)
+			{
+				evicted = !!(schan->ChanFlags & CHAN_JUSTSTARTED);
+			}
+			else
+			{
+				evicted = (pos < len);
+			}
+		}
+		if (!evicted)
+		{
+			ReturnChannel(schan);
+		}
+		else
+		{
+			schan->ChanFlags |= CHAN_EVICTED;
+			schan->SysChannel = nullptr;
+		}
+	}
+}
+
+//==========================================================================
+//
+// S_ChannelVirtualChanged (callback for sound interface code)
+//
+//==========================================================================
+
+void FIChannelList::ChannelVirtualChanged(FISoundChannel *schan, bool is_virtual)
+{
+	if (is_virtual)
+	{
+		schan->ChanFlags |= CHAN_VIRTUAL;
+	}
+	else
+	{
+		schan->ChanFlags &= ~CHAN_VIRTUAL;
+	}
+}
+
+//==========================================================================
+//
+// S_StopChannel
+//
+//==========================================================================
+
+void FIChannelList::StopChannel(FISoundChannel *chan)
+{
+	if (chan == NULL)
+		return;
+
+	if (chan->SysChannel != NULL)
+	{
+		// S_EvictAllChannels() will set the CHAN_EVICTED flag to indicate
+		// that it wants to keep all the channel information around.
+		if (!(chan->ChanFlags & CHAN_EVICTED))
+		{
+			chan->ChanFlags |= CHAN_FORGETTABLE;
+			ChannelStopped(chan);
+
+		}
+		GSnd->StopChannel(chan);
+	}
+	else
+	{
+		ReturnChannel(chan);
+	}
+}
+
+
+//==========================================================================
+//
+// S_EvictAllChannels
+//
+// Forcibly evicts all channels so that there are none playing, but all
+// information needed to restart them is retained.
+//
+//==========================================================================
+
+void FIChannelList::EvictAllChannels()
+{
+	FISoundChannel *chan, *next;
+
+	for (chan = Channels; chan != nullptr; chan = next)
+	{
+		next = chan->NextChan;
+
+		if (!(chan->ChanFlags & CHAN_EVICTED))
+		{
+			chan->ChanFlags |= CHAN_EVICTED;
+			if (chan->SysChannel != nullptr)
+			{
+				if (!(chan->ChanFlags & CHAN_ABSTIME))
+				{
+					chan->StartTime = GSnd ? GSnd->GetPosition(chan) : 0;
+					chan->ChanFlags |= CHAN_ABSTIME;
+				}
+				StopChannel(chan);
+			}
+		}
+	}
+}
+
+//==========================================================================
+//
+// S_RestoreEvictedChannel
+//
+// Recursive helper for S_RestoreEvictedChannels().
+//
+//==========================================================================
+
+void FIChannelList::RestoreEvictedChannel(FISoundChannel *chan)
+{
+	if (chan == NULL)
+	{
+		return;
+	}
+	RestoreEvictedChannel(chan->NextChan);
+	if (chan->ChanFlags & CHAN_EVICTED)
+	{
+		RestartSound(chan);
+		if (!(chan->ChanFlags & CHAN_LOOP))
+		{
+			if (chan->ChanFlags & CHAN_EVICTED)
+			{ // Still evicted and not looping? Forget about it.
+				ReturnChannel(chan);
+			}
+			else if (!(chan->ChanFlags & CHAN_JUSTSTARTED))
+			{ // Should this sound become evicted again, it's okay to forget about it.
+				chan->ChanFlags |= CHAN_FORGETTABLE;
+			}
+		}
+	}
+	else if (chan->SysChannel == NULL && (chan->ChanFlags & (CHAN_FORGETTABLE | CHAN_LOOP)) == CHAN_FORGETTABLE)
+	{
+		ReturnChannel(chan);
+	}
+}
+
+//==========================================================================
+//
+// S_RestoreEvictedChannels
+//
+// Restarts as many evicted channels as possible. Any channels that could
+// not be started and are not looping are moved to the free pool.
+//
+//==========================================================================
+
+void FIChannelList::RestoreEvictedChannels()
+{
+	// Restart channels in the same order they were originally played.
+	RestoreEvictedChannel(Channels);
+}
+