Add a method for effects to create persistent buffer data

al/auxeffectslot.cpp

@@ -460,7 +460,14 @@ START_API_FUNC
                 DecrementRef(oldbuffer->ref);
             slot->Buffer = buffer;
 
-            /* TODO: Create a shared effectstate representation of the buffer. */
+            slot->Effect.Buffer = nullptr;
+            if(buffer)
+            {
+                FPUCtl mixer_mode{};
+                auto *state = slot->Effect.State.get();
+                slot->Effect.Buffer.reset(state->createBuffer(device, buffer->mData.data(),
+                    buffer->Frequency, buffer->mFmtType, buffer->mFmtChannels, buffer->SampleLen));
+            }
         }
         break;
 
@@ -730,6 +737,10 @@ ALenum ALeffectslot::initEffect(ALeffect *effect, ALCcontext *context)
         {
             FPUCtl mixer_mode{};
             State->deviceUpdate(Device);
+            Effect.Buffer = nullptr;
+            if(Buffer)
+                Effect.Buffer.reset(State->createBuffer(Device, Buffer->mData.data(),
+                    Buffer->Frequency, Buffer->mFmtType, Buffer->mFmtChannels, Buffer->SampleLen));
         }
 
         if(!effect)

al/auxeffectslot.h

@@ -50,6 +50,7 @@ struct ALeffectslot {
         EffectProps Props{};
 
         al::intrusive_ptr<EffectState> State;
+        al::intrusive_ptr<EffectBufferBase> Buffer;
     } Effect;
 
     std::atomic_flag PropsClean;

alc/alc.cpp

@@ -2098,6 +2098,12 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const int *attrList)
             EffectState *state{slot->Effect.State.get()};
             state->mOutTarget = device->Dry.Buffer;
             state->deviceUpdate(device);
+            if(ALbuffer *buffer{slot->Buffer})
+            {
+                slot->Effect.Buffer = nullptr;
+                slot->Effect.Buffer.reset(state->createBuffer(device, buffer->mData.data(),
+                    buffer->Frequency, buffer->mFmtType, buffer->mFmtChannels, buffer->SampleLen));
+            }
             slot->updateProps(context);
         }
 
@@ -2119,6 +2125,13 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const int *attrList)
                 EffectState *state{slot->Effect.State.get()};
                 state->mOutTarget = device->Dry.Buffer;
                 state->deviceUpdate(device);
+                if(ALbuffer *buffer{slot->Buffer})
+                {
+                    slot->Effect.Buffer = nullptr;
+                    slot->Effect.Buffer.reset(state->createBuffer(device, buffer->mData.data(),
+                        buffer->Frequency, buffer->mFmtType, buffer->mFmtChannels,
+                        buffer->SampleLen));
+                }
                 slot->updateProps(context);
             }
         }

alc/effects/base.h

@@ -8,6 +8,7 @@
 #include "almalloc.h"
 #include "alspan.h"
 #include "atomic.h"
+#include "buffer_formats.h"
 #include "intrusive_ptr.h"
 
 struct ALeffectslot;
@@ -154,6 +155,10 @@ const EffectVtable T##_vtable = {           \
 }
 
 
+struct EffectBufferBase : public al::intrusive_ref<EffectBufferBase> {
+    virtual ~EffectBufferBase() = default;
+};
+
 struct EffectTarget {
     MixParams *Main;
     RealMixParams *RealOut;
@@ -166,6 +171,14 @@ struct EffectState : public al::intrusive_ref<EffectState> {
     virtual ~EffectState() = default;
 
     virtual void deviceUpdate(const ALCdevice *device) = 0;
+    /* Implementations are currently required to copy the buffer data if they
+     * wish to hold on to it, as there's no guarantee the buffer won't be
+     * detached and deleted or altered during a mix.
+     */
+    virtual EffectBufferBase *createBuffer(const ALCdevice */*device*/,
+        const al::byte */*samplesData*/, ALuint /*sampleRate*/, FmtType /*sampleType*/,
+        FmtChannels /*channelType*/, ALuint /*numSamples*/)
+    { return nullptr; }
     virtual void update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target) = 0;
     virtual void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut) = 0;
 };