implemented stretching mode

src/common/detail/clglcontext.cpp

@@ -60,11 +60,12 @@ CLExecContext_t& CLGLContext::getCLExecContext() {
     return context_;
 }
 
-void CLGLContext::blitFrameBufferToScreen(const cv::Rect& viewport, const cv::Size& windowSize) {
+void CLGLContext::blitFrameBufferToScreen(const cv::Rect& viewport, const cv::Size& windowSize, bool stretch) {
     GL_CHECK(glBindFramebuffer(GL_READ_FRAMEBUFFER, frameBufferID));
     GL_CHECK(glReadBuffer(GL_COLOR_ATTACHMENT0));
     GL_CHECK(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0));
-    GL_CHECK(glBlitFramebuffer(viewport.x, viewport.y, viewport.x + viewport.width, viewport.y + viewport.height, 0, windowSize.height - frameBufferSize_.height, frameBufferSize_.width, windowSize.height, GL_COLOR_BUFFER_BIT, GL_NEAREST));
+    GL_CHECK(glBlitFramebuffer(viewport.x, viewport.y, viewport.x + viewport.width, viewport.y + viewport.height,
+            0, stretch ? 0 : windowSize.height - frameBufferSize_.height, stretch ? windowSize.width : frameBufferSize_.width, windowSize.height, GL_COLOR_BUFFER_BIT, GL_NEAREST));
 }
 
 void CLGLContext::begin() {

src/common/detail/clglcontext.hpp

@@ -35,7 +35,7 @@ class CLGLContext {
     cv::Size frameBufferSize_;
     cv::ogl::Texture2D& getTexture2D();
     CLExecContext_t& getCLExecContext();
-    void blitFrameBufferToScreen(const cv::Rect& viewport, const cv::Size& windowSize);
+    void blitFrameBufferToScreen(const cv::Rect& viewport, const cv::Size& windowSize, bool stretch = false);
 public:
     class FrameBufferScope {
         CLGLContext& ctx_;

src/common/viz2d.cpp

@@ -134,7 +134,7 @@ bool Viz2DWindow::mouse_drag_event(const nanogui::Vector2i &p, const nanogui::Ve
 }
 
 Viz2D::Viz2D(const cv::Size &size, const cv::Size& frameBufferSize, bool offscreen, const string &title, int major, int minor, int samples, bool debug) :
-        initialSize_(size), frameBufferSize_(frameBufferSize), viewport_(0, 0, frameBufferSize.width, frameBufferSize.height), scale_(1), cursor_(0,0), offscreen_(offscreen), title_(title), major_(major), minor_(minor), samples_(samples), debug_(debug) {
+        initialSize_(size), frameBufferSize_(frameBufferSize), viewport_(0, 0, frameBufferSize.width, frameBufferSize.height), scale_(1), cursor_(0,0), offscreen_(offscreen), stretch_(false), title_(title), major_(major), minor_(minor), samples_(samples), debug_(debug) {
     assert(frameBufferSize_.width >= initialSize_.width && frameBufferSize_.height >= initialSize_.height);
     initialize();
 }
@@ -572,6 +572,14 @@ void Viz2D::setOffscreen(bool o) {
     setVisible(!o);
 }
 
+void Viz2D::setStretching(bool s) {
+    stretch_ = s;
+}
+
+bool Viz2D::isStretching() {
+    return stretch_;
+}
+
 nanogui::Window* Viz2D::makeWindow(int x, int y, const string &title) {
     return form()->add_window(nanogui::Vector2i(x, y), title);
 }
@@ -632,7 +640,7 @@ bool Viz2D::display() {
     if (!offscreen_) {
         glfwPollEvents();
         screen().draw_contents();
-        clglContext_->blitFrameBufferToScreen(getViewport(), getWindowSize());
+        clglContext_->blitFrameBufferToScreen(getViewport(), getWindowSize(), isStretching());
         screen().draw_widgets();
         glfwSwapBuffers(glfwWindow_);
         result = !glfwWindowShouldClose(glfwWindow_);

src/common/viz2d.hpp

@@ -62,6 +62,7 @@ class Viz2D: public nanogui::Screen {
     float scale_;
     cv::Vec2f cursor_;
     bool offscreen_;
+    bool stretch_;
     string title_;
     int major_;
     int minor_;
@@ -123,6 +124,8 @@ public:
     void setVisible(bool v);
     bool isOffscreen();
     void setOffscreen(bool o);
+    void setStretching(bool s);
+    bool isStretching();
     bool isClosed();
     void close();
     bool display();

src/optflow/optflow-demo.cpp

@@ -65,6 +65,8 @@ float alpha = 0.05f;
 nanogui::Color effect_color(1.0f, 0.75f, 0.4f, 1.0f);
 //display on-screen FPS
 bool show_fps = true;
+//Stretch frame buffer to window size
+bool stretch = false;
 //Use OpenCL or not
 bool use_acceleration = true;
 //Use a global bloom effect
@@ -303,6 +305,10 @@ void setup_gui(cv::Ptr<kb::viz2d::Viz2D> v2d) {
 
     v2d->makeGroup("Display");
     v2d->makeFormVariable("Show FPS", show_fps, "Enable or disable the On-screen FPS display");
+    v2d->makeFormVariable("Stetch", stretch, "Stretch the frame buffer to the window size")->set_callback([=](const bool& s) {
+        v2d->setStretching(s);
+    });
+
     v2d->form()->add_button("Fullscreen", [=]() {
         v2d->setFullscreen(!v2d->isFullscreen());
     });