From f55409080ba7eca9335f918e4c28f9badfd416ac Mon Sep 17 00:00:00 2001
From: tomaabe <19969980+tomaabe@users.noreply.github.com>
Date: Mon, 8 Jun 2026 14:35:36 +0900
Subject: [PATCH] Fix WASAPI haptic playback truncating clips when endpoint
 rate differs from source

The WASAPI playback path in the Advanced Haptics sample resamples the source
WAV to the haptic audio endpoint's sample rate in
WaveSampleGenerator::GenerateSampleBuffer. The previous code wrote a
whole-integer number of destination blocks per source block via
for (unsigned int j = 0; j < sampleRatio; j++), where sampleRatio is a
float. For any non-integer ratio (endpoint rate != source rate) the block
counts are wrong and the writer reaches the end of the pre-sized render
buffers before all source frames are consumed, so the tail of longer clips
is silently dropped. Symptom: on Play WASAPI (L1) a multi-second clip only
plays/vibrates at the very beginning; Play XAudio2 (R1) is unaffected
because XAudio2 resamples natively.

Replace the integer loop with a phase-accumulator nearest-neighbor resampler
that advances the source by 1 / sampleRatio source frames per destination
frame, correctly handling fractional and downsampling ratios.

Also fix two memory leaks in the same file: FillSampleBuffer now frees each
consumed RenderBuffer, and Flush now frees the remaining RenderBuffers and
restores the queue tail pointer.
---
 .../Audio/WaveSampleGenerator.cpp             | 47 +++++++++++++++----
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/Samples/System/Haptics/HapticsManager/Audio/WaveSampleGenerator.cpp b/Samples/System/Haptics/HapticsManager/Audio/WaveSampleGenerator.cpp
index f298e62c..fffce7a8 100644
--- a/Samples/System/Haptics/HapticsManager/Audio/WaveSampleGenerator.cpp
+++ b/Samples/System/Haptics/HapticsManager/Audio/WaveSampleGenerator.cpp
@@ -292,6 +292,21 @@ namespace ATG
 
         WaveSampleReader reader(pWaveData, waveSize, pSourceWfx);
 
+        // Resample the source to the destination sample rate using nearest-neighbor
+        // selection. A phase accumulator tracks how many source frames have been consumed
+        // versus destination frames written: each destination frame maps back to source
+        // frame (dstFrame / sampleRatio), and the source is advanced until it reaches that
+        // position. This works for any ratio, including fractional ratios and downsampling.
+        constexpr uint32_t nMaxChannels = 8;
+        float currentBlock[nMaxChannels] = {};
+        double srcFramesConsumed = 0.0;   // number of source frames read so far
+        double dstFramesWritten = 0.0;    // number of destination frames written so far
+        bool readerEOF = false;
+
+        // Prime the first source frame.
+        reader.ReadBlock(currentBlock, nMaxChannels);
+        srcFramesConsumed = 1.0;
+
         for (uint32_t i = 0; i < renderBufferCount; i++)
         {
             RenderBuffer* sampleBuffer = new RenderBuffer();
@@ -304,18 +319,23 @@ namespace ATG
 
             while (!writer.IsEOF())
             {
-                constexpr uint32_t nMaxChannels = 8;
-                float channelData[nMaxChannels];
-
-                //  Get a block of channel data (as much as we're interested in).
-                //  If the reader is at end of file then this returns a block
-                //  of zeroed samples.
-                reader.ReadBlock(channelData, nMaxChannels);
-
-                for (unsigned int j = 0; j < sampleRatio; j++)
+                //  Advance the source until it corresponds to the destination frame we are
+                //  about to write (source frame = dstFrame / sampleRatio).
+                double neededSrcFrames = (dstFramesWritten + 1.0) / (double)sampleRatio;
+                while (srcFramesConsumed < neededSrcFrames && !readerEOF)
                 {
-                    writer.WriteBlock(channelData, nMaxChannels);
+                    if (reader.IsEOF())
+                    {
+                        readerEOF = true;
+                        ZeroMemory(currentBlock, sizeof(currentBlock));
+                        break;
+                    }
+                    reader.ReadBlock(currentBlock, nMaxChannels);
+                    srcFramesConsumed += 1.0;
                 }
+
+                writer.WriteBlock(currentBlock, nMaxChannels);
+                dstFramesWritten += 1.0;
             }
 
             *m_SampleQueueTail = sampleBuffer;
@@ -348,6 +368,11 @@ namespace ATG
         CopyMemory(pData, sampleBuffer->Buffer, bytesToRead);
 
         m_SampleQueue = m_SampleQueue->Next;
+        if (m_SampleQueue == nullptr)
+        {
+            m_SampleQueueTail = &m_SampleQueue;
+        }
+        delete sampleBuffer;   // free the consumed buffer (~RenderBuffer frees Buffer)
 
         return S_OK;
     }
@@ -364,6 +389,8 @@ namespace ATG
         {
             RenderBuffer* sampleBuffer = m_SampleQueue;
             m_SampleQueue = sampleBuffer->Next;
+            delete sampleBuffer;   // ~RenderBuffer frees Buffer
         }
+        m_SampleQueueTail = &m_SampleQueue;
     }
 }