Update the context state properties separately

The context state properties are less likely to change compared to the listener
state, and future changes may prefer more infrequent updates to the context
state.

Note that this puts the MetersPerUnit in as a context state, even though it's
handled through the listener functions. Considering the infrequency that it's
updated at (generally set just once for the context's lifetime), it makes more
sense to put it there than with the more frequently updated listener
properties. The aforementioned future changes would also prefer MetersPerUnit
to not be updated unnecessarily.

5 files changed, 69 insertions, 26 deletions

diff --git a/OpenAL32/Include/alListener.h b/OpenAL32/Include/alListener.h
index eb386f7f..ae66b0e3 100644
--- a/OpenAL32/Include/alListener.h
+++ b/OpenAL32/Include/alListener.h
@@ -8,19 +8,23 @@
 extern "C" {
 #endif
 
+struct ALcontextProps {
+    ALfloat DopplerFactor;
+    ALfloat DopplerVelocity;
+    ALfloat SpeedOfSound;
+    ALboolean SourceDistanceModel;
+    enum DistanceModel DistanceModel;
+    ALfloat MetersPerUnit;
+
+    ATOMIC(struct ALcontextProps*) next;
+};
+
 struct ALlistenerProps {
     ALfloat Position[3];
     ALfloat Velocity[3];
     ALfloat Forward[3];
     ALfloat Up[3];
     ALfloat Gain;
-    ALfloat MetersPerUnit;
-
-    ALfloat DopplerFactor;
-    ALfloat DopplerVelocity;
-    ALfloat SpeedOfSound;
-    ALboolean SourceDistanceModel;
-    enum DistanceModel DistanceModel;
 
     ATOMIC(struct ALlistenerProps*) next;
 };
@@ -31,7 +35,6 @@ typedef struct ALlistener {
     ALfloat Forward[3];
     ALfloat Up[3];
     ALfloat Gain;
-    ALfloat MetersPerUnit;
 
     /* Pointer to the most recent property values that are awaiting an update.
      */
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index 614c3b43..95137972 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -382,6 +382,7 @@ struct Hrtf;
 struct HrtfEntry;
 struct FrontStablizer;
 struct Compressor;
+struct ALcontextProps;
 
 
 #define DEFAULT_OUTPUT_RATE  (44100)
@@ -851,6 +852,7 @@ struct ALCcontext_struct {
     ALfloat DopplerFactor;
     ALfloat DopplerVelocity;
     ALfloat SpeedOfSound;
+    ALfloat MetersPerUnit;
     ATOMIC(ALenum) DeferUpdates;
 
     RWLock PropLock;
@@ -863,6 +865,9 @@ struct ALCcontext_struct {
 
     ALfloat GainBoost;
 
+    ATOMIC(struct ALcontextProps*) Update;
+    ATOMIC(struct ALcontextProps*) FreeList;
+
     struct ALvoice **Voices;
     ALsizei VoiceCount;
     ALsizei MaxVoices;
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h
index 1295fee3..2344cc6d 100644
--- a/OpenAL32/Include/alu.h
+++ b/OpenAL32/Include/alu.h
@@ -514,6 +514,8 @@ void aluMixData(ALCdevice *device, ALvoid *OutBuffer, ALsizei NumSamples);
 /* Caller must lock the device. */
 void aluHandleDisconnect(ALCdevice *device);
 
+void UpdateContextProps(ALCcontext *context);
+
 extern ALfloat ConeScale;
 extern ALfloat ZScale;
 extern ALboolean OverrideReverbSpeedOfSound;
diff --git a/OpenAL32/alListener.c b/OpenAL32/alListener.c
index 5a12673d..a4471539 100644
--- a/OpenAL32/alListener.c
+++ b/OpenAL32/alListener.c
@@ -21,7 +21,7 @@
 #include "config.h"
 
 #include "alMain.h"
-#include "AL/alc.h"
+#include "alu.h"
 #include "alError.h"
 #include "alListener.h"
 #include "alSource.h"
@@ -45,8 +45,10 @@ AL_API ALvoid AL_APIENTRY alListenerf(ALenum param, ALfloat value)
     case AL_METERS_PER_UNIT:
         if(!(value >= AL_MIN_METERS_PER_UNIT && value <= AL_MAX_METERS_PER_UNIT))
             SET_ERROR_AND_GOTO(context, AL_INVALID_VALUE, done);
-        context->Listener->MetersPerUnit = value;
-        break;
+        context->MetersPerUnit = value;
+        if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
+            UpdateContextProps(context);
+        goto done;
 
     default:
         SET_ERROR_AND_GOTO(context, AL_INVALID_ENUM, done);
@@ -266,7 +268,7 @@ AL_API ALvoid AL_APIENTRY alGetListenerf(ALenum param, ALfloat *value)
         break;
 
     case AL_METERS_PER_UNIT:
-        *value = context->Listener->MetersPerUnit;
+        *value = context->MetersPerUnit;
         break;
 
     default:
@@ -489,14 +491,6 @@ void UpdateListenerProps(ALCcontext *context)
     props->Up[2] = listener->Up[2];
 
     props->Gain = listener->Gain;
-    props->MetersPerUnit = listener->MetersPerUnit;
-
-    props->DopplerFactor = context->DopplerFactor;
-    props->DopplerVelocity = context->DopplerVelocity;
-    props->SpeedOfSound = context->SpeedOfSound;
-
-    props->SourceDistanceModel = context->SourceDistanceModel;
-    props->DistanceModel = context->DistanceModel;;
 
     /* Set the new container for updating internal parameters. */
     props = ATOMIC_EXCHANGE_PTR(&listener->Update, props, almemory_order_acq_rel);
diff --git a/OpenAL32/alState.c b/OpenAL32/alState.c
index 48c3498a..86534efb 100644
--- a/OpenAL32/alState.c
+++ b/OpenAL32/alState.c
@@ -72,7 +72,7 @@ AL_API ALvoid AL_APIENTRY alEnable(ALenum capability)
         SET_ERROR_AND_GOTO(context, AL_INVALID_ENUM, done);
     }
     if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-        UpdateListenerProps(context);
+        UpdateContextProps(context);
 
 done:
     WriteUnlock(&context->PropLock);
@@ -97,7 +97,7 @@ AL_API ALvoid AL_APIENTRY alDisable(ALenum capability)
         SET_ERROR_AND_GOTO(context, AL_INVALID_ENUM, done);
     }
     if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-        UpdateListenerProps(context);
+        UpdateContextProps(context);
 
 done:
     WriteUnlock(&context->PropLock);
@@ -648,7 +648,7 @@ AL_API ALvoid AL_APIENTRY alDopplerFactor(ALfloat value)
     WriteLock(&context->PropLock);
     context->DopplerFactor = value;
     if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-        UpdateListenerProps(context);
+        UpdateContextProps(context);
     WriteUnlock(&context->PropLock);
 
 done:
@@ -668,7 +668,7 @@ AL_API ALvoid AL_APIENTRY alDopplerVelocity(ALfloat value)
     WriteLock(&context->PropLock);
     context->DopplerVelocity = value;
     if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-        UpdateListenerProps(context);
+        UpdateContextProps(context);
     WriteUnlock(&context->PropLock);
 
 done:
@@ -688,7 +688,7 @@ AL_API ALvoid AL_APIENTRY alSpeedOfSound(ALfloat value)
     WriteLock(&context->PropLock);
     context->SpeedOfSound = value;
     if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-        UpdateListenerProps(context);
+        UpdateContextProps(context);
     WriteUnlock(&context->PropLock);
 
 done:
@@ -713,7 +713,7 @@ AL_API ALvoid AL_APIENTRY alDistanceModel(ALenum value)
     if(!context->SourceDistanceModel)
     {
         if(!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire))
-            UpdateListenerProps(context);
+            UpdateContextProps(context);
     }
     WriteUnlock(&context->PropLock);
 
@@ -779,3 +779,42 @@ done:
 
     return value;
 }
+
+
+void UpdateContextProps(ALCcontext *context)
+{
+    struct ALcontextProps *props;
+
+    /* Get an unused proprty container, or allocate a new one as needed. */
+    props = ATOMIC_LOAD(&context->FreeList, almemory_order_acquire);
+    if(!props)
+        props = al_calloc(16, sizeof(*props));
+    else
+    {
+        struct ALcontextProps *next;
+        do {
+            next = ATOMIC_LOAD(&props->next, almemory_order_relaxed);
+        } while(ATOMIC_COMPARE_EXCHANGE_PTR_WEAK(&context->FreeList, &props, next,
+                almemory_order_seq_cst, almemory_order_acquire) == 0);
+    }
+
+    /* Copy in current property values. */
+    props->MetersPerUnit = context->MetersPerUnit;
+
+    props->DopplerFactor = context->DopplerFactor;
+    props->DopplerVelocity = context->DopplerVelocity;
+    props->SpeedOfSound = context->SpeedOfSound;
+
+    props->SourceDistanceModel = context->SourceDistanceModel;
+    props->DistanceModel = context->DistanceModel;
+
+    /* Set the new container for updating internal parameters. */
+    props = ATOMIC_EXCHANGE_PTR(&context->Update, props, almemory_order_acq_rel);
+    if(props)
+    {
+        /* If there was an unused update container, put it back in the
+         * freelist.
+         */
+        ATOMIC_REPLACE_HEAD(struct ALcontextProps*, &context->FreeList, props);
+    }
+}