we don't need to capture thread_local variables

modules/v4d/samples/beauty-demo.cpp

@@ -229,7 +229,7 @@ static bool iteration(cv::Ptr<V4D> window) {
             return false;
 
         //Save the video frame as BGR
-        window->fb([&](cv::UMat &frameBuffer) {
+        window->fb([](cv::UMat &frameBuffer) {
             cvtColor(frameBuffer, input, cv::COLOR_BGRA2BGR);
         });
 
@@ -249,22 +249,22 @@ static bool iteration(cv::Ptr<V4D> window) {
         if (!faceRect.empty() && facemark->fit(down, faceRects, shapes)) {
             FaceFeatures features(faceRect, shapes[0], float(down.size().width) / WIDTH);
 
-            window->nvg([&]() {
+            window->nvg([&features]() {
                 //Draw the face oval of the first face
                 draw_face_oval_mask(features);
             });
 
-            window->fb([&](cv::UMat &frameBuffer) {
+            window->fb([](cv::UMat &frameBuffer) {
                 //Convert/Copy the mask
                 cvtColor(frameBuffer, faceOval, cv::COLOR_BGRA2GRAY);
             });
 
-            window->nvg([&]() {
+            window->nvg([&features]() {
                 //Draw eyes eyes and lips areas of the first face
                 draw_face_eyes_and_lips_mask(features);
             });
 
-            window->fb([&](cv::UMat &frameBuffer) {
+            window->fb([](cv::UMat &frameBuffer) {
                 //Convert/Copy the mask
                 cvtColor(frameBuffer, eyesAndLipsMaskGrey, cv::COLOR_BGRA2GRAY);
             });
@@ -316,7 +316,7 @@ static bool iteration(cv::Ptr<V4D> window) {
         }
 
         //write the result to the framebuffer
-        window->fb([&](cv::UMat &frameBuffer) {
+        window->fb([](cv::UMat &frameBuffer) {
             cvtColor(frameOut, frameBuffer, cv::COLOR_BGR2BGRA);
         });
 

modules/v4d/samples/cube-demo.cpp

@@ -232,7 +232,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     //To slow for WASM
 #ifndef __EMSCRIPTEN__
     //Aquire the frame buffer for use by OpenCV
-    window->fb([&](cv::UMat& framebuffer) {
+    window->fb([](cv::UMat& framebuffer) {
         glow_effect(framebuffer, framebuffer, glow_kernel_size);
     });
 #endif

modules/v4d/samples/font-demo.cpp

@@ -96,7 +96,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     int32_t translateY = HEIGHT - cnt;
 
     if(update_stars) {
-        window->nvg([&](const cv::Size& sz) {
+        window->nvg([](const cv::Size& sz) {
             using namespace cv::v4d::nvg;
             clear();
 
@@ -112,7 +112,7 @@ static bool iteration(cv::Ptr<V4D> window) {
             }
         });
 
-        window->fb([&](cv::UMat& frameBuffer){
+        window->fb([](cv::UMat& frameBuffer){
             frameBuffer.copyTo(stars);
         });
         update_stars = false;
@@ -129,7 +129,7 @@ static bool iteration(cv::Ptr<V4D> window) {
         update_perspective = false;
     }
 
-    window->nvg([&](const cv::Size& sz) {
+    window->nvg([translateY](const cv::Size& sz) {
         using namespace cv::v4d::nvg;
         clear();
         fontSize(font_size);
@@ -148,7 +148,7 @@ static bool iteration(cv::Ptr<V4D> window) {
         }
     });
 
-    window->fb([&](cv::UMat& framebuffer) {
+    window->fb([](cv::UMat& framebuffer) {
         //Pseudo 3D text effect.
         cv::warpPerspective(framebuffer, warped, tm, framebuffer.size(), cv::INTER_LINEAR, cv::BORDER_CONSTANT, cv::Scalar());
         //Combine layers

modules/v4d/samples/many_cubes-demo.cpp

@@ -233,7 +233,7 @@ static bool iteration(cv::Ptr<V4D> window) {
             window->gl([=](const cv::Size sz){ init_scene(sz, i); }, i);
     });
 
-    window->gl([=](){
+    window->gl([](){
         //Clear the background
         glClearColor(0.2, 0.24, 0.4, 1);
         glClear(GL_COLOR_BUFFER_BIT);
@@ -241,7 +241,7 @@ static bool iteration(cv::Ptr<V4D> window) {
 
     //Render using multiple OpenGL contexts
     for(size_t i = 0; i < NUMBER_OF_CUBES; ++i) {
-        window->gl([=](){
+        window->gl([i](){
             double pos = (((double(i) / NUMBER_OF_CUBES) * 2.0) - 1) + (1.0 / NUMBER_OF_CUBES);
             double angle = sin((double(i) / NUMBER_OF_CUBES) * 2 * M_PI);
             render_scene(pos, pos, angle, i);
@@ -250,7 +250,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     //To slow for WASM
 #ifndef __EMSCRIPTEN__
     //Aquire the frame buffer for use by OpenCV
-    window->fb([&](cv::UMat& framebuffer) {
+    window->fb([](cv::UMat& framebuffer) {
         glow_effect(framebuffer, framebuffer, glow_kernel_size);
     });
 #endif

modules/v4d/samples/nanovg-demo.cpp

@@ -141,7 +141,7 @@ static bool iteration(cv::Ptr<V4D> window) {
         return false;
 
     //Acquire the framebuffer and convert it to RGB
-    window->fb([&](cv::UMat &framebuffer) {
+    window->fb([](cv::UMat &framebuffer) {
         cvtColor(framebuffer, rgb, cv::COLOR_BGRA2RGB);
     });
 
@@ -159,12 +159,12 @@ static bool iteration(cv::Ptr<V4D> window) {
     cv::cvtColor(hsv, rgb, cv::COLOR_HSV2RGB_FULL);
 
     //Acquire the framebuffer and convert the rgb into it
-    window->fb([&](cv::UMat &framebuffer) {
+    window->fb([](cv::UMat &framebuffer) {
         cv::cvtColor(rgb, framebuffer, cv::COLOR_BGR2BGRA);
     });
 
     //Render using nanovg
-    window->nvg([&](const cv::Size &sz) {
+    window->nvg([hue](const cv::Size &sz) {
         draw_color_wheel(sz.width - 300, sz.height - 300, 250.0f, 250.0f, hue);
     });
 

modules/v4d/samples/optflow-demo.cpp

@@ -406,18 +406,20 @@ static bool iteration(cv::Ptr<V4D> window) {
     if(!window->capture())
         return false;
 
+    static thread_local cv::Size fbSz = window->framebufferSize();
     //BGRA
     static thread_local cv::UMat background, down;
-    static thread_local cv::UMat foreground(window->framebufferSize(), CV_8UC4, cv::Scalar::all(0));
+    static thread_local cv::UMat foreground(fbSz, CV_8UC4, cv::Scalar::all(0));
     //BGR
     static thread_local cv::UMat miniFrame;
     //GREY
     static thread_local cv::UMat downPrevGrey, downNextGrey, downMotionMaskGrey;
     static thread_local vector<cv::Point2f> detectedPoints;
 
-    window->fb([&](cv::UMat& frameBuffer) {
+
+    window->fb([](cv::UMat& frameBuffer) {
         //resize to foreground scale
-        cv::resize(frameBuffer, down, cv::Size(window->framebufferSize().width * fg_scale, window->framebufferSize().height * fg_scale));
+        cv::resize(frameBuffer, down, cv::Size(fbSz.width * fg_scale, fbSz.height * fg_scale));
         //save video background
         frameBuffer.copyTo(background);
     });
@@ -428,7 +430,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     //Detect trackable points in the motion mask
     detect_points(downMotionMaskGrey, detectedPoints);
 
-    window->nvg([&]() {
+    window->nvg([]() {
         cv::v4d::nvg::clear();
         if (!downPrevGrey.empty()) {
             //We don't want the algorithm to get out of hand when there is a scene change, so we suppress it when we detect one.
@@ -442,7 +444,7 @@ static bool iteration(cv::Ptr<V4D> window) {
 
     downPrevGrey = downNextGrey.clone();
 
-    window->fb([&](cv::UMat& framebuffer){
+    window->fb([](cv::UMat& framebuffer){
         //Put it all together (OpenCL)
         composite_layers(background, foreground, framebuffer, framebuffer, glow_kernel_size, fg_loss, background_mode, post_proc_mode);
         cvtColor(framebuffer, miniFrame, cv::COLOR_BGRA2RGB);

modules/v4d/samples/pedestrian-demo.cpp

@@ -148,7 +148,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     if(!window->capture())
         return false;
 
-    window->fb([&](cv::UMat& frameBuffer){
+    window->fb([](cv::UMat& frameBuffer){
     	//copy video frame
         cvtColor(frameBuffer,videoFrame,cv::COLOR_BGRA2RGB);
         //downsample video frame for hog detection
@@ -200,7 +200,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     }
 
     //Draw an ellipse around the tracked pedestrian
-    window->nvg([&](const cv::Size& sz) {
+    window->nvg([](const cv::Size& sz) {
         using namespace cv::v4d::nvg;
         clear();
         beginPath();
@@ -215,7 +215,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     });
 
     //Put it all together
-    window->fb([&](cv::UMat& frameBuffer){
+    window->fb([](cv::UMat& frameBuffer){
         composite_layers(background, frameBuffer, frameBuffer, BLUR_KERNEL_SIZE);
     });
 

modules/v4d/samples/video-demo.cpp

@@ -200,7 +200,7 @@ static bool iteration(cv::Ptr<V4D> window) {
     window->gl(render_scene);
 
 #ifndef __EMSCRIPTEN__
-    window->fb([&](cv::UMat& frameBuffer) {
+    window->fb([](cv::UMat& frameBuffer) {
         glow_effect(frameBuffer, frameBuffer, glow_kernel_size);
     });
 #endif