capping timestep at 15 FPS

4 files changed, 5 insertions, 3 deletions

diff --git a/gate/src/app_info.rs b/gate/src/app_info.rs
index 90dc1e7..80364a0 100644
--- a/gate/src/app_info.rs
+++ b/gate/src/app_info.rs
@@ -103,7 +103,7 @@ impl AppInfo {
 
     /// Specifies the target frames-per-second (default is `60.`).
     pub fn target_fps(mut self, target_fps: f64) -> Self {
-        assert!(target_fps > 10. && target_fps < 200., "unrealistic target_fps: {}", target_fps);
+        assert!(target_fps >= 20. && target_fps < 200., "unrealistic target_fps: {}", target_fps);
         self.target_fps = target_fps;
         self
     }
diff --git a/gate/src/core/sdl/mod.rs b/gate/src/core/sdl/mod.rs
index e4006c1..4072096 100644
--- a/gate/src/core/sdl/mod.rs
+++ b/gate/src/core/sdl/mod.rs
@@ -100,7 +100,7 @@ pub fn run<AS: AppAssetId, AP: App<AS>>(info: AppInfo, mut app: AP) {
 
         event_handler.process_events(&mut app, &mut ctx, &renderer);
         if ctx.close_requested() { break; }
-        app.advance(elapsed, &mut ctx);
+        app.advance(elapsed.min(::MAX_TIMESTEP), &mut ctx);
         if ctx.close_requested() { break; }
     }
 }
diff --git a/gate/src/core/wasm/mod.rs b/gate/src/core/wasm/mod.rs
index ccdce54..541f920 100644
--- a/gate/src/core/wasm/mod.rs
+++ b/gate/src/core/wasm/mod.rs
@@ -121,7 +121,7 @@ impl<AS: AppAssetId, AP: App<AS>> TraitAppRunner for AppRunner<AS, AP> {
     fn update_and_draw(&mut self, time_sec: f64) {
         let elapsed = self.last_time_sec.map(|x| time_sec - x).unwrap_or(0.0).max(0.0).min(0.1);
         if elapsed > 0.0 {
-            self.app.advance(elapsed, &mut self.ctx);
+            self.app.advance(elapsed.min(::MAX_TIMESTEP), &mut self.ctx);
         }
         self.last_time_sec = Some(time_sec);
 
diff --git a/gate/src/lib.rs b/gate/src/lib.rs
index 72b4e40..bbbd375 100644
--- a/gate/src/lib.rs
+++ b/gate/src/lib.rs
@@ -73,6 +73,8 @@ pub use app_info::AppInfo;
 use asset_id::AppAssetId;
 use renderer::Renderer;
 
+const MAX_TIMESTEP: f64 = 1. / 15.;
+
 /// Invoke this in a `main` method to run the `App`.
 ///
 /// Will panic if this method is called more than once.