From facb922f3e1d39af8514916c990acd9ff9d8baae Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Fri, 26 Nov 2010 17:47:43 -0800
Subject: Properly clamp high pitch values

---
 Alc/ALu.c              | 59 ++++++++++++++++++++++++++++++--------------------
 Alc/mixer.c            | 17 ---------------
 OpenAL32/Include/alu.h | 15 ++++++++++++-
 3 files changed, 49 insertions(+), 42 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 9619f595..a6151a10 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -104,34 +104,40 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
     SourceVolume = ALSource->flGain;
     MinVolume    = ALSource->flMinGain;
     MaxVolume    = ALSource->flMaxGain;
+    Pitch        = ALSource->flPitch;
 
     //1. Multi-channel buffers always play "normal"
     Channels = 0;
-    Pitch = ALSource->flPitch;
     BufferListItem = ALSource->queue;
     while(BufferListItem != NULL)
     {
         ALbuffer *ALBuffer;
         if((ALBuffer=BufferListItem->buffer) != NULL)
         {
-            Channels = aluChannelsFromFormat(ALBuffer->format);
+            ALint maxstep = STACK_DATA_SIZE /
+                            aluFrameSizeFromFormat(ALBuffer->format);
+            maxstep -= ResamplerPadding[ALSource->Resampler] +
+                       ResamplerPrePadding[ALSource->Resampler] + 1;
+            maxstep = min(maxstep, INT_MAX>>FRACTIONBITS);
+
             Pitch = Pitch * ALBuffer->frequency / Frequency;
+            if(Pitch > (ALfloat)maxstep)
+                ALSource->Params.Step = maxstep<<FRACTIONBITS;
+            else
+            {
+                ALSource->Params.Step = Pitch*FRACTIONONE;
+                if(ALSource->Params.Step == 0)
+                    ALSource->Params.Step = 1;
+                else if(ALSource->Params.Step > maxstep)
+                    ALSource->Params.Step = maxstep;
+            }
+
+            Channels = aluChannelsFromFormat(ALBuffer->format);
             break;
         }
         BufferListItem = BufferListItem->next;
     }
 
-    if(Pitch > (float)MAX_PITCH)
-        ALSource->Params.Step = MAX_PITCH<<FRACTIONBITS;
-    else if(!(Pitch > 0.0f))
-        ALSource->Params.Step = FRACTIONONE;
-    else
-    {
-        ALSource->Params.Step = Pitch*FRACTIONONE;
-        if(ALSource->Params.Step == 0)
-            ALSource->Params.Step = 1;
-    }
-
     DryGain = SourceVolume;
     DryGain = __min(DryGain,MaxVolume);
     DryGain = __max(DryGain,MinVolume);
@@ -587,23 +593,28 @@ ALvoid CalcSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         ALbuffer *ALBuffer;
         if((ALBuffer=BufferListItem->buffer) != NULL)
         {
+            ALint maxstep = STACK_DATA_SIZE /
+                            aluFrameSizeFromFormat(ALBuffer->format);
+            maxstep -= ResamplerPadding[ALSource->Resampler] +
+                       ResamplerPrePadding[ALSource->Resampler] + 1;
+            maxstep = min(maxstep, INT_MAX>>FRACTIONBITS);
+
             Pitch = Pitch * ALBuffer->frequency / Frequency;
+            if(Pitch > (ALfloat)maxstep)
+                ALSource->Params.Step = maxstep<<FRACTIONBITS;
+            else
+            {
+                ALSource->Params.Step = Pitch*FRACTIONONE;
+                if(ALSource->Params.Step == 0)
+                    ALSource->Params.Step = 1;
+                else if(ALSource->Params.Step > maxstep)
+                    ALSource->Params.Step = maxstep;
+            }
             break;
         }
         BufferListItem = BufferListItem->next;
     }
 
-    if(Pitch > (float)MAX_PITCH)
-        ALSource->Params.Step = MAX_PITCH<<FRACTIONBITS;
-    else if(!(Pitch > 0.0f))
-        ALSource->Params.Step = FRACTIONONE;
-    else
-    {
-        ALSource->Params.Step = Pitch*FRACTIONONE;
-        if(ALSource->Params.Step == 0)
-            ALSource->Params.Step = 1;
-    }
-
     // Use energy-preserving panning algorithm for multi-speaker playback
     length = __max(OrigDist, MinDist);
     if(length > 0.0f)
diff --git a/Alc/mixer.c b/Alc/mixer.c
index 53ba4aca..18c93b84 100644
--- a/Alc/mixer.c
+++ b/Alc/mixer.c
@@ -612,12 +612,6 @@ DECL_TEMPLATE(ALubyte, cubic8)
 #undef DECL_TEMPLATE
 
 
-/* Stack data size can be whatever. Larger values need more stack, while
- * smaller values may need more iterations */
-#ifndef STACK_DATA_SIZE
-#define STACK_DATA_SIZE  16384
-#endif
-
 ALvoid MixSource(ALsource *Source, ALCdevice *Device, ALuint SamplesToDo)
 {
     ALbufferlistitem *BufferListItem;
@@ -859,17 +853,6 @@ ALvoid MixSource(ALsource *Source, ALCdevice *Device, ALuint SamplesToDo)
 
         BufferSize = (ALuint)((DataSize64+(increment-1)) / increment);
         BufferSize = min(BufferSize, (SamplesToDo-OutPos));
-        if(BufferSize == 0)
-        {
-            AL_PRINT("No samples to mix! Pitch too high (%u, %g)?\n",
-                     increment, increment/(double)FRACTIONONE);
-            State = AL_STOPPED;
-            BufferListItem = Source->queue;
-            BuffersPlayed = Source->BuffersInQueue;
-            DataPosInt = 0;
-            DataPosFrac = 0;
-            break;
-        }
 
         SrcData += BufferPrePadding*FrameSize;
         switch(Resampler)
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h
index 31d42ea9..c157a529 100644
--- a/OpenAL32/Include/alu.h
+++ b/OpenAL32/Include/alu.h
@@ -80,7 +80,20 @@ typedef enum {
 #define FRACTIONBITS (14)
 #define FRACTIONONE  (1<<FRACTIONBITS)
 #define FRACTIONMASK (FRACTIONONE-1)
-#define MAX_PITCH    (INT_MAX & ~FRACTIONMASK)
+
+/* Size for temporary stack storage of buffer data. Larger values need more
+ * stack, while smaller values may need more iterations. The value needs to be
+ * a sensible size, however, as it constrains the max stepping value used for
+ * mixing.
+ * The mixer requires being able to do two samplings per mixing loop. A 16KB
+ * buffer can hold 512 sample frames for a 7.1 float buffer. With the cubic
+ * resampler (which requires 3 padding sample frames), this limits the maximum
+ * step to about 508. This means that buffer_freq*source_pitch cannot exceed
+ * device_freq*508 for an 8-channel 32-bit buffer. */
+#ifndef STACK_DATA_SIZE
+#define STACK_DATA_SIZE  16384
+#endif
+
 
 /* NOTE: The AL_FORMAT_REAR* enums aren't handled here because they're
  *       converted to AL_FORMAT_QUAD* when loaded */
-- 
cgit v1.2.3