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.

1 files changed, 45 insertions, 6 deletions

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);
+    }
+}