Simplify zoom and adapt for larger models

crates/fj-viewer/src/input/event.rs

@@ -9,7 +9,17 @@ pub enum Event {
     Key(Key, KeyState),
 
     /// The user scrolled
-    Scroll(f64),
+    Scroll(MouseScrollDelta),
+}
+
+/// Describes a difference in the mouse scroll wheel state.
+pub enum MouseScrollDelta {
+    /// Amount in lines to scroll in the horizontal direction.
+    ///
+    /// Positive values indicate movement forward (away from the user).
+    Line(f64),
+    /// Amount in pixels to scroll in the vertical direction.
+    Pixel(f64),
 }
 
 /// A keyboard or mouse key

crates/fj-viewer/src/input/mod.rs

@@ -7,6 +7,6 @@ mod rotation;
 mod zoom;
 
 pub use self::{
-    event::{Event, Key, KeyState},
+    event::{Event, Key, KeyState, MouseScrollDelta},
     handler::{Actions, Handler},
 };

crates/fj-viewer/src/input/zoom.rs

@@ -2,6 +2,8 @@ use fj_math::{Transform, Vector};
 
 use crate::camera::{Camera, FocusPoint};
 
+use super::event::MouseScrollDelta;
+
 pub struct Zoom {
     accumulated_delta: f64,
 }
@@ -13,9 +15,12 @@ impl Zoom {
         }
     }
 
-    pub fn push(&mut self, delta: f64) {
+    pub fn push(&mut self, delta: MouseScrollDelta) {
         // Accumulate all zoom inputs
-        self.accumulated_delta += delta;
+        self.accumulated_delta += match delta {
+            MouseScrollDelta::Line(delta) => ZOOM_FACTOR_LINE * delta,
+            MouseScrollDelta::Pixel(delta) => ZOOM_FACTOR_PIXEL * delta,
+        };
     }
 
     pub fn apply_to_camera(
@@ -28,19 +33,23 @@ impl Zoom {
             Some(fp) => (fp - camera.position()).magnitude(),
             None => camera.position().coords.magnitude(),
         };
-        let displacement = self.accumulated_delta
-            * delta_t
-            * ZOOM_FACTOR
-            * distance.into_f64();
+        let displacement =
+            self.accumulated_delta * delta_t * distance.into_f64();
         camera.translation = camera.translation
             * Transform::translation(Vector::from([0.0, 0.0, -displacement]));
 
         self.accumulated_delta = 0.;
     }
 }
 
-/// Affects the speed of zoom movement.
+/// Affects the speed of zoom movement given a scroll wheel input in lines.
+///
+/// Smaller values will move the camera less with the same input.
+/// Larger values will move the camera more with the same input.
+const ZOOM_FACTOR_LINE: f64 = 15.0;
+
+/// Affects the speed of zoom movement given a scroll wheel input in pixels.
 ///
 /// Smaller values will move the camera less with the same input.
 /// Larger values will move the camera more with the same input.
-const ZOOM_FACTOR: f64 = 0.1;
+const ZOOM_FACTOR_PIXEL: f64 = 1.0;

crates/fj-window/src/run.rs

@@ -165,16 +165,14 @@ pub fn run(
             Event::WindowEvent {
                 event: WindowEvent::MouseWheel { delta, .. },
                 ..
-            } => {
-                let delta = match delta {
-                    MouseScrollDelta::LineDelta(_, y) => y as f64 * 10.0,
-                    MouseScrollDelta::PixelDelta(PhysicalPosition {
-                        y,
-                        ..
-                    }) => y,
-                };
-                Some(input::Event::Scroll(delta))
-            }
+            } => Some(input::Event::Scroll(match delta {
+                MouseScrollDelta::LineDelta(_, y) => {
+                    input::MouseScrollDelta::Line(y as f64)
+                }
+                MouseScrollDelta::PixelDelta(PhysicalPosition {
+                    y, ..
+                }) => input::MouseScrollDelta::Pixel(y),
+            })),
             Event::MainEventsCleared => {
                 let delta_t = now.duration_since(previous_time);
                 previous_time = now;