[PATCH 1/4] xaudio2: Implement IXAudio2SourceVoice frequency functions

[Chris Robinson]

On 09/15/2015 10:25 AM, Andrew Eikum wrote:
> @@ -801,14 +802,26 @@ static HRESULT WINAPI XA2SRC_SetFrequencyRatio(IXAudio2SourceVoice *iface,
>           float Ratio, UINT32 OperationSet)
>   {
>       XA2SourceImpl *This = impl_from_IXAudio2SourceVoice(iface);
> +
>       TRACE("%p, %f, 0x%x\n", This, Ratio, OperationSet);
> +
> +    EnterCriticalSection(&This->lock);
> +
> +    This->freq_ratio = Ratio;
> +    This->freq = This->fmt->nSamplesPerSec * Ratio;
> +
> +    LeaveCriticalSection(&This->lock);
> +
>       return S_OK;
...
> @@ -816,7 +829,16 @@ static HRESULT WINAPI XA2SRC_SetSourceSampleRate(
>       UINT32 NewSourceSampleRate)
>   {
>       XA2SourceImpl *This = impl_from_IXAudio2SourceVoice(iface);
> +
>       TRACE("%p, %u\n", This, NewSourceSampleRate);
> +
> +    EnterCriticalSection(&This->lock);
> +
> +    This->fmt->nSamplesPerSec = NewSourceSampleRate;
> +    This->freq = NewSourceSampleRate * This->freq_ratio;
> +
> +    LeaveCriticalSection(&This->lock);
> +
>       return S_OK;
>   }
...
> @@ -2989,7 +3012,7 @@ static BOOL xa2buffer_queue_period(XA2SourceImpl *src, XA2Buffer *buf, ALuint al
>       buf->offs_bytes += submit_bytes;
>
>       alBufferData(al_buf, src->al_fmt, submit_buf, submit_bytes,
> -            src->fmt->nSamplesPerSec);
> +            src->freq);
>
>       alSourceQueueBuffers(src->al_src, 1, &al_buf);
>

This doesn't strike me as correct. Assuming the SampleRate or 
FrequencyRatio can be altered in real-time, this will break the OpenAL 
buffer queue which needs to have the same sample rate on each buffer. 
SetFrequencyRatio looks like it'd map directly to the AL source's pitch 
property, while SetSourceSampleRate may be a bit trickier depending on 
when it's allowed to be called (it'd require stopping the source and 
clearing the queue, then rebuffering and requeueing the buffers to start 
where it left off).

Also, I notice the OperationSet parameter isn't used. What is that for?