Defer occlusion query destruction to avoid usage overlap.

src/bgfx.cpp

@@ -1511,6 +1511,12 @@ namespace bgfx
 			destroyDynamicVertexBufferInternal(m_freeDynamicVertexBufferHandle[ii]);
 		}
 		m_numFreeDynamicVertexBufferHandles = 0;
+
+		for (uint16_t ii = 0, num = m_numFreeOcclusionQueryHandles; ii < num; ++ii)
+		{
+			m_occlusionQueryHandle.free(m_freeOcclusionQueryHandle[ii].idx);
+		}
+		m_numFreeOcclusionQueryHandles = 0;
 	}
 
 	void Context::freeAllHandles(Frame* _frame)

src/bgfx_p.h

@@ -2194,6 +2194,7 @@ namespace bgfx
 			, m_submit(&m_frame[BGFX_CONFIG_MULTITHREADED ? 1 : 0])
 			, m_numFreeDynamicIndexBufferHandles(0)
 			, m_numFreeDynamicVertexBufferHandles(0)
+			, m_numFreeOcclusionQueryHandles(0)
 			, m_colorPaletteDirty(0)
 			, m_instBufferCount(0)
 			, m_frames(0)
@@ -3620,7 +3621,8 @@ namespace bgfx
 		BGFX_API_FUNC(void destroyOcclusionQuery(OcclusionQueryHandle _handle) )
 		{
 			BGFX_CHECK_HANDLE("destroyOcclusionQuery", m_occlusionQueryHandle, _handle);
-			m_occlusionQueryHandle.free(_handle.idx);
+
+			m_freeOcclusionQueryHandle[m_numFreeOcclusionQueryHandles++] = _handle;
 		}
 
 		BGFX_API_FUNC(void saveScreenShot(const char* _filePath) )
@@ -4120,8 +4122,10 @@ namespace bgfx
 
 		uint16_t m_numFreeDynamicIndexBufferHandles;
 		uint16_t m_numFreeDynamicVertexBufferHandles;
-		DynamicIndexBufferHandle m_freeDynamicIndexBufferHandle[BGFX_CONFIG_MAX_DYNAMIC_INDEX_BUFFERS];
+		uint16_t m_numFreeOcclusionQueryHandles;
+		DynamicIndexBufferHandle  m_freeDynamicIndexBufferHandle[BGFX_CONFIG_MAX_DYNAMIC_INDEX_BUFFERS];
 		DynamicVertexBufferHandle m_freeDynamicVertexBufferHandle[BGFX_CONFIG_MAX_DYNAMIC_VERTEX_BUFFERS];
+		OcclusionQueryHandle      m_freeOcclusionQueryHandle[BGFX_CONFIG_MAX_OCCLUSION_QUERIES];
 
 		NonLocalAllocator m_dynIndexBufferAllocator;
 		bx::HandleAllocT<BGFX_CONFIG_MAX_DYNAMIC_INDEX_BUFFERS> m_dynamicIndexBufferHandle;