show fps in all demos

src/font/font-demo.cpp

@@ -133,9 +133,9 @@ int main(int argc, char **argv) {
             cv::add(stars, warped, frameBuffer);
         });
 
-        v2d->writeVA();
+        update_fps(v2d, true);
 
-        update_fps(v2d, false);
+        v2d->writeVA();
 
         //If onscreen rendering is enabled it displays the framebuffer in the native window. Returns false if the window was closed.
         if(!v2d->display())

src/nanovg/nanovg-demo.cpp

@@ -173,9 +173,9 @@ int main(int argc, char **argv) {
             drawColorwheel(sz.width - 300, sz.height - 300, 250.0f, 250.0f, hue);
         });
 
-        v2d->writeVA();
+        update_fps(v2d, true);
 
-        update_fps(v2d, false);
+        v2d->writeVA();
 
         //If onscreen rendering is enabled it displays the framebuffer in the native window. Returns false if the window was closed.
         if(!v2d->display())

src/optflow/optflow-demo.cpp

@@ -301,10 +301,10 @@ int main(int argc, char **argv) {
             composite_layers(background, foreground, frameBuffer, frameBuffer, glow_kernel_size, fg_loss);
         });
 
-        v2d->writeVA();
-
         update_fps(v2d, show_fps);
 
+        v2d->writeVA();
+
         //If onscreen rendering is enabled it displays the framebuffer in the native window. Returns false if the window was closed.
         if(!v2d->display())
             break;

src/tetra/tetra-demo.cpp

@@ -6,7 +6,7 @@
 constexpr long unsigned int WIDTH = 1920;
 constexpr long unsigned int HEIGHT = 1080;
 constexpr double FPS = 60;
-constexpr bool OFFSCREEN = false;
+constexpr bool OFFSCREEN = true;
 constexpr const char* OUTPUT_FILENAME = "tetra-demo.mkv";
 constexpr const int VA_HW_DEVICE_INDEX = 0;
 constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
@@ -102,9 +102,9 @@ int main(int argc, char **argv) {
             glow_effect(frameBuffer, frameBuffer, glow_kernel_size);
         });
 
-        v2d->writeVA();
+        update_fps(v2d, true);
 
-        update_fps(v2d, false);
+        v2d->writeVA();
 
         //If onscreen rendering is enabled it displays the framebuffer in the native window. Returns false if the window was closed.
         if (!v2d->display())

src/video/video-demo.cpp

@@ -118,6 +118,7 @@ int main(int argc, char **argv) {
             glow_effect(frameBuffer, frameBuffer, glow_kernel_size);
         });
 
+        update_fps(v2d, true);
 
         v2d->writeVA();