[Change] Tried to fix stupid fucking animation jitter

client/src/game_state.cpp

@@ -154,7 +154,11 @@ void GameState::update(void) {
         }
       }
       if(_desktop) {
-        _desktop->update();
+        /*
+         * TODO: These fuck'in window dimensions just need to be global at this point!!
+         * Pass GameState by reference ?
+         */
+        _desktop->update(_screen_width, _screen_height);
       }
       break;
     }

client/src/ui/desktop.cpp

@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <chrono>
 #include <ctime>
 #include <fstream>
 #include <cmath>
@@ -40,12 +41,14 @@ Desktop::Desktop(int screen_width, int screen_height, ClientNetwork* network) {
   }
 
   /* Init animated background. */
-  srand(time(NULL));
   for(int i = 0; i < 100; ++i) {
+    float y_pos = (float)(rand() % screen_height);
     _background_text.push_back(
       {get_random_snippet(_snippets), (float)(rand() % screen_width),
-      (float)(rand() % screen_height),
+        y_pos,
-      (float)(rand() % 30 + 10) / 100.0f});
+        (float)(rand() % 30 + 10) / 100.0f,
+        (int)y_pos
+      });
   }
 }
 
@@ -141,8 +144,9 @@ void Desktop::handle_event(SDL_Event* event, int screen_width, int screen_height
   }
 }
 
-void Desktop::update(void) {
+void Desktop::update(int screen_width, int screen_height) {
   /* Remove closed windows. */
+  _update_wallpaper(screen_width, screen_height);
   _windows.erase(std::remove_if(_windows.begin(), _windows.end(),
                                 [this](const std::unique_ptr<UIWindow>& w) {
                                   if (w->should_close()) {
@@ -182,14 +186,19 @@ void Desktop::render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer,
 void Desktop::_render_wallpaper(TextRenderer* txt_renderer) {
   const Color wallpaper_color = { 0.0f, 0.15f, 0.08f };
   for(auto& line : _background_text) {
-    line.y -= line.speed;
+    txt_renderer->render_text(line.text.c_str(), std::round(line.x),
-    if(line.y < 0) {
+                              line.render_y, 1.0f, wallpaper_color);
-      line.y = 720;                     /* TODO: Use screen_height. */
+  }
-      line.x = (float)(rand() % 1280);  /* TODO: Use screen_width. */
+}
+
+void Desktop::_update_wallpaper(int screen_width, int screen_height) {
+  for(auto& line : _background_text) {
+    line.y_precise -= line.speed;
+    line.render_y = static_cast<int>(std::round(line.y_precise));
+    if(line.render_y < 0) {
+      line.y_precise = screen_height;
+      line.x = (float)(rand() % screen_width);
       line.text = get_random_snippet(_snippets);
     }
-    /* Round positions to nearest int to prevent jitter. */
-    txt_renderer->render_text(line.text.c_str(), std::round(line.x),
-                              std::round(line.y), 1.0f, wallpaper_color);
   }
 }

client/src/ui/desktop.h

@@ -15,8 +15,9 @@
 struct ScrollingText {
   std::string text;
   float x;
-  float y;
+  float y_precise; /* sub-pixel animation. */
   float speed;
+  int render_y;    /* For pixel-perfect rendering. */
 };
 
 class Desktop {
@@ -26,7 +27,7 @@ public:
 
   void add_window(std::unique_ptr<UIWindow> window);
   void handle_event(SDL_Event* event, int screen_width, int screen_height);
-  void update(void);
+  void update(int screen_width, int screen_height);
   void render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer, int screen_height,
               bool show_cursor);
 
@@ -35,6 +36,7 @@ public:
 private:
   void _set_focused_window(UIWindow* window);
   void _render_wallpaper(TextRenderer* txt_renderer);
+  void _update_wallpaper(int screen_width, int screen_height);
 
   std::vector<std::unique_ptr<UIWindow>> _windows;
   std::unique_ptr<Taskbar>   _taskbar;