fixed race condition

modules/v4d/src/detail/clvacontext.cpp

@@ -64,7 +64,7 @@ void CLVAContext::write(std::function<void(const cv::UMat&)> fn, const cv::UMat&
 #ifndef __EMSCRIPTEN__
         CLExecScope_t scope(context_);
 #endif
-        fn(videoFrame_);
+        fn(videoFrame_.clone());
     }
 }
 

modules/v4d/src/detail/framebuffercontext.cpp

@@ -60,11 +60,7 @@ FrameBufferContext::FrameBufferContext(const cv::Size& frameBufferSize, bool off
     glfwWindowHint(GLFW_ALPHA_BITS, 8);
     glfwWindowHint(GLFW_STENCIL_BITS, 8);
     glfwWindowHint(GLFW_DEPTH_BITS, 24);
-#ifndef __EMSCRIPTEN__
-    glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
-#else
     glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
-#endif
     glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
 
 //    glfwWindowHint(GLFW_DOUBLEBUFFER, GL_FALSE);

modules/v4d/src/v4d.cpp

@@ -358,7 +358,7 @@ bool V4D::capture(std::function<void(cv::UMat&)> fn) {
         }
     }
 
-    currentReaderFrame_ = nextReaderFrame_;
+    currentReaderFrame_ = nextReaderFrame_.clone();
     fb([=,this](cv::UMat frameBuffer) {
         currentReaderFrame_.copyTo(frameBuffer);
     });