fix overlay flickering on nvidia

modules/v4d/include/opencv2/v4d/v4d.hpp

@@ -400,6 +400,7 @@ private:
     bool hasNvgCtx();
     bool hasNguiCtx();
     bool hasGlCtx(uint32_t idx = 0);
+    size_t numGlCtx();
 
     GLFWwindow* getGLFWWindow();
     void swapContextBuffers();

modules/v4d/src/detail/framebuffercontext.cpp

@@ -33,7 +33,7 @@ static bool contains_absolute(nanogui::Widget* w, const nanogui::Vector2i& p) {
 
 int frameBufferContextCnt = 0;
 
-FrameBufferContext::FrameBufferContext(V4D& v4d, const string& title, const FrameBufferContext& other) : FrameBufferContext(v4d, other.framebufferSize_, true, title, other.major_,  other.minor_, other.compat_, other.samples_, other.debug_, other.glfwWindow_, &other) {
+FrameBufferContext::FrameBufferContext(V4D& v4d, const string& title, const FrameBufferContext& other) : FrameBufferContext(v4d, other.framebufferSize_, !other.debug_, title, other.major_,  other.minor_, other.compat_, other.samples_, other.debug_, other.glfwWindow_, &other) {
 }
 
 FrameBufferContext::FrameBufferContext(V4D& v4d, const cv::Size& framebufferSize, bool offscreen,
@@ -136,12 +136,12 @@ void FrameBufferContext::initWebGLCopy(FrameBufferContext& dst) {
 
 void FrameBufferContext::doWebGLCopy(FrameBufferContext& dst) {
 #ifdef __EMSCRIPTEN__
-    int width = dst.getWindowSize().width;
-    int height = dst.getWindowSize().height;
+    int width = getWindowSize().width;
+    int height = getWindowSize().height;
     {
         FrameBufferContext::GLScope glScope(dst, GL_READ_FRAMEBUFFER);
         dst.blitFrameBufferToScreen(
-                cv::Rect(0,0, width, height),
+                cv::Rect(0,0, dst.size().width, dst.size().height),
                 dst.getWindowSize(),
                 false);
         emscripten_webgl_commit_frame();
@@ -253,7 +253,7 @@ void FrameBufferContext::init() {
 #else
     glfwWindowHint(GLFW_VISIBLE, GLFW_TRUE);
 #endif
-    glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_FALSE);
+    glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_TRUE);
     glfwWindow_ = glfwCreateWindow(framebufferSize_.width, framebufferSize_.height, title_.c_str(), nullptr,
             sharedWindow_);
 

modules/v4d/src/detail/nanoguicontext.cpp

@@ -15,11 +15,11 @@ NanoguiContext::NanoguiContext(FrameBufferContext& fbContext) :
         mainFbContext_(fbContext), nguiFbContext_(fbContext.getV4D(), "NanoGUI", fbContext), context_(
                 nullptr), copyBuffer_(mainFbContext_.size(), CV_8UC4) {
     run_sync_on_main<25>([&, this]() {
-        {
-            //Workaround for first frame glitch
-            FrameBufferContext::GLScope glScope(fbCtx(), GL_FRAMEBUFFER);
-            FrameBufferContext::FrameBufferScope fbScope(fbCtx(), copyBuffer_);
-        }
+//        {
+//            //Workaround for first frame glitch
+//            FrameBufferContext::GLScope glScope(fbCtx(), GL_FRAMEBUFFER);
+//            FrameBufferContext::FrameBufferScope fbScope(fbCtx(), copyBuffer_);
+//        }
         {
 #ifndef __EMSCRIPTEN__
             mainFbContext_.makeCurrent();
@@ -66,21 +66,25 @@ void NanoguiContext::render(bool printFPS, bool showFPS, bool showTracking) {
         }
 #endif
         {
+
 #ifndef __EMSCRIPTEN__
+            float w = mainFbContext_.getWindowSize().width;
+            float h = mainFbContext_.getWindowSize().height;
             mainFbContext_.makeCurrent();
             GL_CHECK(glFinish());
             GL_CHECK(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0));
-            GL_CHECK(glViewport(0, 0, mainFbContext_.getWindowSize().width, mainFbContext_.getWindowSize().height));
-            glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+            GL_CHECK(glViewport(0, 0, w, h));
+            GL_CHECK(glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT));
 #else
+            float w = fbCtx().size().width;
+            float h = fbCtx().size().height;
             FrameBufferContext::GLScope glScope(fbCtx(), GL_FRAMEBUFFER);
+            GL_CHECK(glViewport(0, 0, w, h));
             GL_CHECK(glClearColor(0,0,0,0));
             GL_CHECK(glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT));
-            GL_CHECK(glViewport(0, 0, mainFbContext_.getWindowSize().width, mainFbContext_.getWindowSize().height));
 #endif
 
-            float w = mainFbContext_.size().width;
-            float h = mainFbContext_.size().height;
+
             float r = mainFbContext_.pixelRatioX();
             if(showFPS || showTracking) {
                 nvgSave(context_);
@@ -103,8 +107,6 @@ void NanoguiContext::render(bool printFPS, bool showFPS, bool showTracking) {
                 textAlign(NVG_ALIGN_LEFT | NVG_ALIGN_MIDDLE);
                 text(7.5, 15, txt.c_str(), nullptr);
 
-                nvgEndFrame(context_);
-                nvgRestore(context_);
             }
 
             if(showTracking) {
@@ -112,7 +114,9 @@ void NanoguiContext::render(bool printFPS, bool showFPS, bool showTracking) {
                 std::stringstream ss;
                 auto& tiMap = TimeTracker::getInstance()->getMap();
                 size_t cnt = 0;
-                beginPath();
+#ifdef __EMSCRIPTEN__
+                fbCtx().makeCurrent();
+#endif
                 fontSize(20.0f);
                 fontFace("mono");
                 fillColor(cv::Scalar(200, 200, 200, 200));
@@ -124,14 +128,13 @@ void NanoguiContext::render(bool printFPS, bool showFPS, bool showTracking) {
                     text(7.5, 15 * (cnt + 3), ss.str().c_str(), nullptr);
                     ++cnt;
                 }
+
+            }
+
+            if(showFPS || showTracking) {
                 nvgEndFrame(context_);
                 nvgRestore(context_);
             }
-        }
-        {
-#ifdef __EMSCRIPTEN__
-            FrameBufferContext::GLScope glScope(fbCtx(), GL_FRAMEBUFFER);
-#endif
             screen().draw_widgets();
 #ifndef __EMSCRIPTEN__
             GL_CHECK(glFinish());

modules/v4d/src/v4d.cpp

@@ -141,6 +141,11 @@ bool V4D::hasGlCtx(uint32_t idx) {
     return glContexts_.find(idx) != glContexts_.end();
 }
 
+size_t V4D::numGlCtx() {
+    return glContexts_.size();
+}
+
+
 void V4D::gl(std::function<void()> fn, uint32_t idx) {
     TimeTracker::getInstance()->execute("gl(" + detail::func_id(fn) + ")/" + std::to_string(idx), [&](){
         glCtx(idx).render([=](const cv::Size& sz) {
@@ -219,7 +224,10 @@ void V4D::run(std::function<bool(cv::Ptr<V4D>)> fn) {
     }
     pool_.finish();
 #else
-    emscripten_set_main_loop_arg(do_frame, &fn, -1, true);
+    std::function<bool()> fnFrame([=,this](){
+        return fn(self());
+    });
+    emscripten_set_main_loop_arg(do_frame, &fnFrame, -1, true);
 #endif
 }
 
@@ -454,13 +462,15 @@ void V4D::setDefaultKeyboardEventCallback() {
 
 void V4D::swapContextBuffers() {
     run_sync_on_main<10>([this]() {
-        FrameBufferContext::GLScope glScope(glCtx().fbCtx(), GL_READ_FRAMEBUFFER);
-        glCtx().fbCtx().blitFrameBufferToScreen(viewport(), glCtx().fbCtx().getWindowSize(), isScaling());
+        for(size_t i = 0; i < numGlCtx(); ++i) {
+            FrameBufferContext::GLScope glScope(glCtx(i).fbCtx(), GL_READ_FRAMEBUFFER);
+            glCtx(i).fbCtx().blitFrameBufferToScreen(viewport(), glCtx(i).fbCtx().getWindowSize(), isScaling());
 #ifndef __EMSCRIPTEN__
-        glfwSwapBuffers(glCtx().fbCtx().getGLFWWindow());
+            glfwSwapBuffers(glCtx(i).fbCtx().getGLFWWindow());
 #else
-        emscripten_webgl_commit_frame();
+            emscripten_webgl_commit_frame();
 #endif
+        }
     });
 
     run_sync_on_main<11>([this]() {
@@ -492,7 +502,8 @@ bool V4D::display() {
     if (true) {
 #endif
 
-//        swapContextBuffers();
+        if(debug_)
+            swapContextBuffers();
 
 #ifdef __EMSCRIPTEN__
         nguiCtx().render(printFPS_, showFPS_, showTracking_);