Update camera with delta time

src/camera.rs

@@ -1,3 +1,5 @@
+use std::time::Duration;
+
 use winit::event::{ElementState, KeyboardInput, VirtualKeyCode, WindowEvent};
 
 pub struct Camera {
@@ -108,19 +110,23 @@ impl CameraController {
         }
     }
 
-    pub fn update_camera(&self, camera: &mut Camera) {
+    pub fn update_camera(&self, camera: &mut Camera, delta_time: Duration) {
         use cgmath::InnerSpace;
         let forward = camera.target - camera.eye;
         let forward_norm = forward.normalize();
         let forward_mag = forward.magnitude();
 
+        // Calculate the speed taking into account the delta time
+        let speed = self.speed * delta_time.as_secs_f32();
+        println!("speed: {}, delta_time: {:?}", speed, delta_time);
+
         // Prevents glitching when the camera gets too close to the
         // center of the scene.
-        if self.is_forward_pressed && forward_mag > self.speed {
+        if self.is_forward_pressed && forward_mag > speed {
-            camera.eye += forward_norm * self.speed;
+            camera.eye += forward_norm * speed;
         }
         if self.is_backward_pressed {
-            camera.eye -= forward_norm * self.speed;
+            camera.eye -= forward_norm * speed;
         }
 
         let right = forward_norm.cross(camera.up);
@@ -133,10 +139,10 @@ impl CameraController {
             // Rescale the distance between the target and the eye so
             // that it doesn't change. The eye, therefore, still
             // lies on the circle made by the target and eye.
-            camera.eye = camera.target - (forward + right * self.speed).normalize() * forward_mag;
+            camera.eye = camera.target - (forward + right * speed).normalize() * forward_mag;
         }
         if self.is_left_pressed {
-            camera.eye = camera.target - (forward - right * self.speed).normalize() * forward_mag;
+            camera.eye = camera.target - (forward - right * speed).normalize() * forward_mag;
         }
     }
 }

src/lib.rs

@@ -1,4 +1,5 @@
 use cgmath::prelude::*;
+use std::time::{Duration, Instant};
 use wgpu::util::DeviceExt;
 use winit::{
     dpi::LogicalSize,
@@ -53,6 +54,7 @@ pub async fn run() {
     }
 
     let mut state = State::new(window).await;
+    let mut last_update = Instant::now();
 
     event_loop.run(move |event, _, control_flow| {
         match event {
@@ -98,6 +100,11 @@ pub async fn run() {
             Event::MainEventsCleared => {
                 // RedrawRequested will only trigger once unless we manually
                 // request it.
+
+                let now = Instant::now();
+                state.delta_time = now - last_update;
+                last_update = now;
+
                 state.window().request_redraw();
             }
             _ => {}
@@ -127,6 +134,7 @@ pub struct State {
     instance_buffer: wgpu::Buffer,
     depth_texture: Texture,
     obj_model: Model,
+    delta_time: Duration,
 }
 
 impl State {
@@ -295,7 +303,7 @@ impl State {
             label: Some("diffuse_bind_group"),
         });
 
-        let camera_controller = CameraController::new(0.2);
+        let camera_controller = CameraController::new(10.0);
 
         let camera = Camera {
             // position the camera 1 unit up and 2 units back
@@ -423,6 +431,7 @@ impl State {
             instance_buffer,
             depth_texture,
             obj_model,
+            delta_time: Duration::default(),
         }
     }
 
@@ -446,7 +455,7 @@ impl State {
     }
 
     fn update(&mut self) {
-        self.camera_controller.update_camera(&mut self.camera);
+        self.camera_controller.update_camera(&mut self.camera, self.delta_time);
         self.camera_uniform.update_view_proj(&self.camera);
         self.queue.write_buffer(
             &self.camera_buffer,