Debug FPS display with rendering backend info

src/main.rs

@@ -394,6 +394,8 @@ struct App {
     ws_id: i32,
     match_mode: bool,
     coop: bool,
+    fps: f32,
+    renderer: String,
 }
 
 impl App {
@@ -600,7 +602,7 @@ async fn main() {
     let seed = (miniquad::date::now() * 1000.0) as u32 | 1;
     // behind the title menu: the endless bridge battle
     let (game, cam) = Game::new_demo(seed);
-    let mut app = App { game, cam, settings, seed, status: None, recorded: false, client: MatchClient::new(), ws_id: 0, match_mode: false, coop: false };
+    let mut app = App { game, cam, settings, seed, status: None, recorded: false, client: MatchClient::new(), ws_id: 0, match_mode: false, coop: false, fps: 0.0, renderer: platform::renderer() };
     menu.progress = platform::storage_get(PROGRESS_KEY).and_then(|s| serde_json::from_str(&s).ok()).unwrap_or_default();
     app.game.hints = app.settings.hints;
     let mut inp = Input { ldown: None, rdown: None, rlast: (0.0, 0.0), rdrag: false, mlast: None, minimap_drag: false, tlast: None, touch_world: false, inspect: None };
@@ -614,8 +616,11 @@ async fn main() {
     let mut cache_t = 0.0f32;
 
     loop {
-        let dt = get_frame_time().min(0.1);
+        let raw_dt = get_frame_time();
+        let dt = raw_dt.min(0.1);
         let now = get_time();
+        let fps_now = 1.0 / raw_dt.max(0.001);
+        app.fps = if app.fps <= 0.0 { fps_now } else { app.fps + (fps_now - app.fps) * 0.08 };
         let mut settings_changed = false;
 
         // ---------------- touch or mouse: which interface is active
@@ -1423,4 +1428,32 @@ fn draw_frame(app: &mut App, gfx: &Gfx, r3d: &mut R3d, ui: &mut Ui, menu: &mut M
     if !touch {
         ui.draw_cursor(gfx, &app.game, now, blocked);
     }
+    if app.settings.debug_fps {
+        draw_debug_fps(app, gfx);
+    }
+}
+
+fn draw_debug_fps(app: &App, gfx: &Gfx) {
+    ui::begin_ui();
+    let scale = ui::SMALL().max(1.0);
+    let fps = app.fps.max(0.0).round() as i32;
+    let renderer = {
+        let r = app.renderer.trim();
+        if r.is_empty() {
+            if cfg!(target_arch = "wasm32") {
+                "WebGL"
+            } else {
+                "OpenGL"
+            }
+        } else {
+            r
+        }
+    };
+    let max_cols = (((ui::sw() - 6.0) / ui::CW()).floor() as i32).max(12) as usize;
+    let line: String = format!("{} FPS  {}", fps, renderer).chars().take(max_cols).collect();
+    let w = gfx.measure(&line, scale);
+    let x = (ui::sw() - w - 2.0).max(2.0);
+    let y = 2.0;
+    draw_rectangle(x - 2.0, y - 2.0, w + 4.0, scale * 10.0 + 4.0, Color::from_rgba(0, 0, 0, 150));
+    gfx.text(&line, x, y, scale, GOLD);
 }