sync triple buffering

cocos2d/cocos2d-x#20585
zhongfq · Nov 24, 2020 · 65a887b · 65a887b
1 parent 3c423ec
commit 65a887b
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/frameworks/cocos2d-x/cocos/renderer/backend/metal/BufferMTL.h b/frameworks/cocos2d-x/cocos/renderer/backend/metal/BufferMTL.h
@@ -86,7 +86,7 @@ class BufferMTL : public Buffer
     void beginFrame();
 
 private:
-    void updateIndex();
+    void inflightBuffer(std::size_t offset, std::size_t size);
 
     id<MTLBuffer> _mtlBuffer = nil;
     NSMutableArray* _dynamicDataBuffers = nil;

diff --git a/frameworks/cocos2d-x/cocos/renderer/backend/metal/BufferMTL.mm b/frameworks/cocos2d-x/cocos/renderer/backend/metal/BufferMTL.mm
@@ -71,14 +71,14 @@ of this software and associated documentation files (the "Software"), to deal
 void BufferMTL::updateData(void* data, std::size_t size)
 {
     assert(size <= _size);
-    updateIndex();
+    inflightBuffer(0, size);
     memcpy((uint8_t*)_mtlBuffer.contents, data, size);
 }
 
 void BufferMTL::updateSubData(void* data, std::size_t offset, std::size_t size)
 {
     assert(offset + size <= _size);
-    updateIndex();
+    inflightBuffer(offset, size);
     memcpy((uint8_t*)_mtlBuffer.contents + offset, data, size);
 }
 
@@ -92,12 +92,22 @@ of this software and associated documentation files (the "Software"), to deal
     _indexUpdated = false;
 }
 
-void BufferMTL::updateIndex()
+void BufferMTL::inflightBuffer(std::size_t offset, std::size_t size)
 {
     if (BufferUsage::DYNAMIC == _usage && !_indexUpdated)
     {
         _currentFrameIndex = (_currentFrameIndex + 1) % MAX_INFLIGHT_BUFFER;
+        id<MTLBuffer> prevFrameBuffer = _mtlBuffer;
         _mtlBuffer = _dynamicDataBuffers[_currentFrameIndex];
+        if(offset)
+        {
+            memcpy((uint8_t*)_mtlBuffer.contents, prevFrameBuffer.contents, offset);
+        }
+        offset += size;
+        if(offset < _size)
+        {
+            memcpy((uint8_t*)_mtlBuffer.contents + offset, (uint8_t*)prevFrameBuffer.contents + offset, _size - offset);
+        }
         _indexUpdated = true;
     }
 }