Allow paning / zooming viewport

connorslade · Jan 27, 2025 · 90aa038 · 90aa038
1 parent 6c6ed4d
commit 90aa038
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Showing 4 changed files with 45 additions and 17 deletions.
diff --git a/src/main.rs b/src/main.rs
@@ -188,7 +188,13 @@ impl App<'_> {
 
         self.renderer.render(self, &mut encoder, &view);
         self.egui.render(gc, &mut encoder, &view, |ctx| {
-            self.gui.ui(ctx, gc, &mut self.simulation, &mut self.fps);
+            self.gui.ui(
+                ctx,
+                gc,
+                &mut self.simulation,
+                &mut self.renderer,
+                &mut self.fps,
+            );
         });
 
         let snapshot = self

diff --git a/src/renderer.rs b/src/renderer.rs
@@ -1,5 +1,3 @@
-use std::mem;
-
 use anyhow::Result;
 use encase::{ShaderType, UniformBuffer};
 use image::{GenericImageView, ImageBuffer, Rgba};
@@ -26,6 +24,7 @@ pub struct Renderer {
     context: Buffer,
 
     pub pan: Vector2<f32>,
+    pub zoom: f32,
 }
 
 #[derive(ShaderType, Default)]
@@ -37,6 +36,9 @@ pub struct RenderContext {
     flags: u32,
     gain: f32,
     energy_gain: f32,
+
+    pan: Vector2<f32>,
+    zoom: f32,
 }
 
 impl Renderer {
@@ -78,9 +80,7 @@ impl Renderer {
                     ty: BindingType::Buffer {
                         ty: BufferBindingType::Uniform,
                         has_dynamic_offset: false,
-                        min_binding_size: BufferSize::new(
-                            dbg!(mem::size_of::<RenderContext>()) as _
-                        ),
+                        min_binding_size: BufferSize::new(48),
                     },
                     count: None,
                 },
@@ -138,6 +138,7 @@ impl Renderer {
             context,
 
             pan: Vector2::zeros(),
+            zoom: 1.0,
         }
     }
 
@@ -177,6 +178,8 @@ impl Renderer {
                 // TODO: move out of simulation
                 gain: app.simulation.gain,
                 energy_gain: app.simulation.energy_gain,
+                pan: self.pan,
+                zoom: self.zoom,
             })
             .unwrap();
         gc.queue

diff --git a/src/shaders/render.wgsl b/src/shaders/render.wgsl
@@ -11,15 +11,18 @@ struct Context {
     // 1 << 1: energy_view
     flags: u32,
     gain: f32,
-    energy_gain: f32
+    energy_gain: f32,
+
+    pan: vec2<f32>,
+    zoom: f32,
 }
 
 // VERTEX SHADER //
 
 struct VertexOutput {
     @builtin(position)
     position: vec4<f32>,
-};
+}
 
 @vertex
 fn vert(
@@ -52,20 +55,16 @@ fn index(x: u32, y: u32, n: u32) -> u32 {
 
 @fragment
 fn frag(in: VertexOutput) -> @location(0) vec4<f32> {
-    // ↓ Use vector operations
-    let x_offset = ctx.window.x / 2 - ctx.size.x / 2;
-    let y_offset = ctx.window.y / 2 - ctx.size.y / 2;
-    let x = i32(in.position.x) - i32(x_offset);
-    let y = i32(in.position.y) - i32(y_offset);
+    let pos = vec2<i32>((in.position.xy - ctx.pan)  * ctx.zoom );
 
-    if x == -1 || y == -1 || x == i32(ctx.size.x) || y == i32(ctx.size.y) {
+    if pos.x == -1 || pos.y == -1 || pos.x == i32(ctx.size.x) || pos.y == i32(ctx.size.y) {
         return vec4<f32>(0.0, 0.0, 0.0, 1.0);
-    } else if x < 0 || x > i32(ctx.size.x) || y < 0 || y > i32(ctx.size.y) {
+    } else if pos.x < 0 || pos.x > i32(ctx.size.x) || pos.y < 0 || pos.y > i32(ctx.size.y) {
         return vec4<f32>(1.0, 1.0, 1.0, 1.0);
     }
 
     if (ctx.flags & 0x02) != 0 {
-        var val = clamp(average_energy[u32(y) * ctx.size.x + u32(x)] * ctx.energy_gain, 0.0, 1.0);
+        var val = clamp(average_energy[u32(pos.y) * ctx.size.x + u32(pos.x)] * ctx.energy_gain, 0.0, 1.0);
         let scheme_index = u32(val * 3.0);
         val = val * 3.0 - f32(scheme_index);
 
@@ -86,7 +85,7 @@ fn frag(in: VertexOutput) -> @location(0) vec4<f32> {
         return vec4<f32>(color, 1.0);
     }
 
-    let val = states[index(u32(x), u32(y), ctx.tick % 3)] * ctx.gain;
+    let val = states[index(u32(pos.x), u32(pos.y), ctx.tick % 3)] * ctx.gain;
     let color = (
           vec3<f32>(0.0, 0.0, 1.0) * f32(val > 0.0)
         + vec3<f32>(1.0, 0.0, 0.0) * f32(val < 0.0)

diff --git a/src/ui.rs b/src/ui.rs
@@ -2,9 +2,11 @@ use std::time::{Duration, Instant};
 
 use bitflags::Flags;
 use egui::{emath::Numeric, Color32, Context, DragValue, RichText, Slider, Ui, Window};
+use nalgebra::Vector2;
 use wgpu::{Buffer, CommandEncoder};
 
 use crate::{
+    renderer::Renderer,
     simulation::{Simulation, SimulationFlags},
     FpsTracker, GraphicsContext,
 };
@@ -31,12 +33,30 @@ impl Gui {
         ctx: &Context,
         gc: &GraphicsContext,
         simulation: &mut Simulation,
+        render: &mut Renderer,
         fps: &mut FpsTracker,
     ) {
         let now = Instant::now();
         let frame_time = now - fps.last_frame;
         fps.last_frame = now;
 
+        let dragging_viewport = ctx.dragged_id().is_none();
+        let scale_factor = gc.window.scale_factor() as f32;
+
+        ctx.input(|input| {
+            let pointer = input.pointer.latest_pos().unwrap_or_default();
+            let pointer = Vector2::new(pointer.x, pointer.y) * scale_factor;
+
+            let old_zoom = render.zoom;
+            render.zoom = (old_zoom + input.smooth_scroll_delta.y / 1000.0).max(0.05);
+            render.pan += (pointer - render.pan) * (1.0 - (old_zoom / render.zoom));
+
+            if input.pointer.any_down() && dragging_viewport {
+                let delta = input.pointer.delta() * scale_factor;
+                render.pan += Vector2::new(delta.x, delta.y);
+            }
+        });
+
         Window::new("Wave Simulator")
             .default_width(0.0)
             .show(ctx, |ui| {