Display player speed in km/h

src/app.rs

@@ -13,7 +13,7 @@ use crate::{
     game::{for_each_tile_on_screen, Biome, GameState},
     graphics::{self, NATIVE_RESOLUTION},
     input::Input,
-    math::{wp_to_tp, WorldPos, TILE_SIZE},
+    math::{px_per_frame_to_km_h, wp_to_tp, WorldPos, TILE_SIZE},
     res::Res,
     world::Tile,
 };
@@ -264,8 +264,16 @@ fn debug_panel_ui(
                 "Player offset from center: {}",
                 LengthDisp(tp.x as i64 - wp_to_tp(WorldPos::CENTER) as i64)
             ));
-            ui.label(format!("Hspeed: {}", game.player.hspeed));
-            ui.label(format!("Vspeed: {}", game.player.vspeed));
+            ui.label(format!(
+                "Hspeed: {} ({} km/h)",
+                game.player.hspeed,
+                px_per_frame_to_km_h(game.player.hspeed)
+            ));
+            ui.label(format!(
+                "Vspeed: {} ({} km/h)",
+                game.player.vspeed,
+                px_per_frame_to_km_h(game.player.vspeed)
+            ));
             ui.label("Gravity");
             ui.add(egui::DragValue::new(&mut game.gravity));
         }

src/graphics.rs

@@ -5,6 +5,8 @@ use sfml::{
 };
 use sfml_xt::graphics::RenderWindowExt;
 
+use crate::math::FPS_TARGET;
+
 pub struct ScreenRes {
     pub w: i16,
     pub h: i16,
@@ -44,7 +46,7 @@ pub fn make_window() -> RenderWindow {
         Style::CLOSE,
         &ContextSettings::default(),
     );
-    rw.set_framerate_limit(60);
+    rw.set_framerate_limit(FPS_TARGET.into());
     rw.center();
     rw
 }

src/math.rs

@@ -9,6 +9,18 @@ pub struct WorldPos {
 }
 
 pub const TILE_SIZE: u8 = 32;
+/// Pixels per meter. One meter = one tile, so this is the same as `TILE_SIZE`.
+pub const PX_PER_M: u8 = TILE_SIZE;
+pub const FPS_TARGET: u8 = 60;
+
+pub fn px_per_frame_to_m_per_s(px_per_frame: f32) -> f32 {
+    let m_per_frame = px_per_frame / PX_PER_M as f32;
+    m_per_frame * FPS_TARGET as f32
+}
+
+pub fn px_per_frame_to_km_h(px_per_frame: f32) -> f32 {
+    px_per_frame_to_m_per_s(px_per_frame) * 3.6
+}
 
 impl WorldPos {
     pub fn tile_pos(&self) -> TilePos {