render the model

Cargo.lock

@@ -156,9 +156,9 @@ checksum = "5dd9dc738b7a8311c7ade152424974d8115f2cdad61e8dab8dac9f2362298510"
 
 [[package]]
 name = "bytemuck"
-version = "1.24.0"
+version = "1.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fbdf580320f38b612e485521afda1ee26d10cc9884efaaa750d383e13e3c5f4"
+checksum = "95832e849adfb21180ccb6826a99da14e5d266ae5c2e668e1602cf234f153797"
 dependencies = [
  "bytemuck_derive",
 ]
@@ -505,6 +505,9 @@ name = "glam"
 version = "0.30.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19fc433e8437a212d1b6f1e68c7824af3aed907da60afa994e7f542d18d12aa9"
+dependencies = [
+ "bytemuck",
+]
 
 [[package]]
 name = "glow"
@@ -624,6 +627,7 @@ checksum = "dfa686283ad6dd069f105e5ab091b04c62850d3e4cf5d67debad1933f55023df"
 name = "hyperboloid"
 version = "0.1.0"
 dependencies = [
+ "bytemuck",
  "glam",
  "pollster",
  "wgpu",

Cargo.toml

@@ -18,7 +18,8 @@ debug = false
 opt-level = 3
 
 [dependencies]
-glam = { version = "0.30.9" }
+bytemuck = { version = "1.25.2", features = ["derive"] }
+glam = { version = "0.30.9", features = ["bytemuck"] }
 pollster = "0.4.0"
 wgpu = "27.0.1"
 winit = "0.30.12"

src/camera.rs

@@ -0,0 +1,47 @@
+use glam::{Mat4, Vec3, vec3};
+
+/// A camera always directed at the origin.
+#[derive(Debug, Clone, Copy)]
+pub struct OrbitalCamera {
+	/// Horizontal position (angle), in radians from +X towards +Y.
+	pub position_yaw: f32,
+
+	/// Vertical position (angle), in radians from XY plane towards +Z.
+	pub position_pitch: f32,
+
+	/// Distance from the origin.
+	pub distance: f32,
+}
+
+impl OrbitalCamera {
+	pub fn position(&self) -> Vec3 {
+		let (y, x) = self.position_yaw.sin_cos();
+		let (z, xy) = self.position_pitch.sin_cos();
+		self.distance * vec3(xy * x, xy * y, z)
+	}
+
+	pub fn direction(&self) -> Vec3 {
+		let (y, x) = self.position_yaw.sin_cos();
+		let (z, xy) = self.position_pitch.sin_cos();
+		-vec3(xy * x, xy * y, z)
+	}
+
+	pub fn transform(&self) -> Mat4 {
+		// for yaw=0, pitch=0:
+		// X -> -Z
+		// Y -> -X
+		// Z -> Y
+		Mat4::from_translation(vec3(0., 0., self.distance))
+			* Mat4::from_cols_array_2d(&[
+				[0., 0., -1., 0.],
+				[-1., 0., 0., 0.],
+				[0., 1., 0., 0.],
+				[0., 0., 0., 1.],
+			]) * Mat4::from_euler(
+			glam::EulerRot::ZYZ,
+			0.,
+			self.position_pitch,
+			-self.position_yaw,
+		)
+	}
+}

src/lib.rs

@@ -1,22 +1,56 @@
 use std::error::Error;
 
-use glam::{UVec2, Vec4, vec4};
+use glam::{Mat4, UVec2, Vec4, vec4};
 
+mod camera;
 mod mesh;
+mod render;
 
 const DEPTH_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Depth16Unorm;
 const OUTPUT_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Bgra8UnormSrgb;
 
+#[derive(Debug, Clone, Copy)]
+#[repr(C)]
+pub struct ShapeArgs {
+	pub sides: u32,
+	pub layers_up: u32,
+	pub layers_down: u32,
+	pub base_diameter: f32,
+	pub height: f32,
+}
+
+impl Default for ShapeArgs {
+	fn default() -> Self {
+		Self {
+			sides: 24,
+			layers_up: 6,
+			layers_down: 6,
+			base_diameter: 36.0,
+			height: 120.0,
+		}
+	}
+}
+
 #[derive(Debug, Clone, Copy)]
 #[repr(C)]
 pub struct RedrawArgs {
+	pub shape: ShapeArgs,
 	pub background: Vec4,
+	pub camera_yaw: f32,
+	pub camera_pitch: f32,
+	pub light_yaw: f32,
+	pub light_pitch: f32,
 }
 
 impl Default for RedrawArgs {
 	fn default() -> Self {
 		Self {
+			shape: ShapeArgs::default(),
 			background: vec4(0.05, 0.20, 0.85, 1.00),
+			camera_yaw: std::f32::consts::FRAC_PI_2,
+			camera_pitch: std::f32::consts::FRAC_PI_3,
+			light_yaw: 0.,
+			light_pitch: 2. * std::f32::consts::FRAC_PI_3,
 		}
 	}
 }
@@ -33,6 +67,8 @@ pub struct Core {
 	surface: wgpu::Surface<'static>,
 
 	depth: wgpu::Texture,
+
+	pipeline: render::Pipeline,
 }
 
 impl Core {
@@ -48,21 +84,40 @@ impl Core {
 
 		Self::configure_surface(&surface, &device, pixel_size);
 
+		let pipeline = render::Pipeline::new(&device);
+
 		Self {
 			device,
 			queue,
 			surface,
 			depth,
+			pipeline,
 		}
 	}
 
 	fn render(&self, output: &wgpu::Texture, args: &RedrawArgs) {
+		let mesh = mesh::generate();
+		let mesh = faceted_mesh(&mesh);
+		let mesh = render::Mesh::new(&self.device, &mesh);
+
 		let aspect = {
 			let size = output.size();
 			let w = size.width as f32;
 			let h = size.height as f32;
 			w / h
 		};
+		let camera = camera::OrbitalCamera {
+			position_yaw: args.camera_yaw,
+			position_pitch: args.camera_pitch,
+			distance: 5. * args.shape.base_diameter,
+		};
+		let perspective = Mat4::perspective_lh(std::f32::consts::FRAC_PI_3, aspect, 1e1, 1e3);
+		self.pipeline.set_look(
+			&self.queue,
+			render::LookParams {
+				m: perspective * camera.transform(),
+			},
+		);
 		self.queue.submit([]); // flush buffer updates
 
 		let view = output.create_view(&wgpu::TextureViewDescriptor::default());
@@ -98,6 +153,8 @@ impl Core {
 			..Default::default()
 		});
 
+		self.pipeline.render(&mut pass, [&mesh]);
+
 		drop(pass);
 		self.queue.submit(std::iter::once(encoder.finish()));
 	}
@@ -177,3 +234,16 @@ pub async fn init_gpu_inner<E: Error + 'static>(
 		surface,
 	})
 }
+
+fn faceted_mesh(mesh: &mesh::Mesh) -> Vec<render::Vertex> {
+	let mut ret = Vec::new();
+	for face in &mesh.faces {
+		let face = face.map(|index| mesh.vertices[index]);
+		let u = face[1] - face[0];
+		let v = face[2] - face[0];
+		let normal = u.cross(v).normalize();
+		let face = face.map(|position| render::Vertex { position, normal });
+		ret.extend(face);
+	}
+	ret
+}

src/mesh.wgsl

@@ -0,0 +1,27 @@
+struct LookParams {
+	m: mat4x4f,
+}
+
+struct Vertex {
+	@location(0) position: vec3f,
+	@location(1) normal: vec3f,
+}
+
+struct Varying {
+	@builtin(position) screen: vec4f,
+	@location(0) normal: vec3f,
+}
+
+@group(0) @binding(0) var<uniform> look: LookParams;
+
+@vertex
+fn on_vertex(in: Vertex) -> Varying {
+	let pos = look.m * vec4f(in.position, 1.0);
+	let normal = in.normal;
+	return Varying(pos, normal);
+}
+
+@fragment
+fn on_fragment(in: Varying) -> @location(0) vec4f {
+	return vec4f(0.5 + 0.5 * in.normal, 1.0);
+}

src/render.rs

@@ -0,0 +1,148 @@
+use std::mem::offset_of;
+
+use bytemuck::{Pod, Zeroable, bytes_of, cast_slice};
+use glam::{Mat4, Vec3};
+use wgpu::util::DeviceExt as _;
+
+use crate::{DEPTH_FORMAT, OUTPUT_FORMAT};
+
+static MESH_SHADER: &str = include_str!("mesh.wgsl");
+
+#[derive(Debug, Clone, Copy, Pod, Zeroable)]
+#[repr(C)]
+pub struct LookParams {
+	pub m: Mat4,
+}
+
+#[derive(Debug, Clone, Copy, Zeroable, Pod)]
+#[repr(C)]
+pub struct Vertex {
+	pub position: Vec3,
+	pub normal: Vec3,
+}
+
+pub struct Mesh {
+	vertex_buffer: wgpu::Buffer,
+	vertex_count: u32,
+}
+
+impl Mesh {
+	pub fn new(device: &wgpu::Device, vertices: &[Vertex]) -> Self {
+		let vertex_count = vertices.len().try_into().expect("too many vertices");
+		let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+			label: None,
+			usage: wgpu::BufferUsages::VERTEX,
+			contents: cast_slice(vertices),
+		});
+		Self {
+			vertex_buffer,
+			vertex_count,
+		}
+	}
+}
+
+pub struct Pipeline {
+	look_buf: wgpu::Buffer,
+	bindings: wgpu::BindGroup,
+	pipeline: wgpu::RenderPipeline,
+}
+
+impl Pipeline {
+	pub fn new(device: &wgpu::Device) -> Self {
+		let look_buf = device.create_buffer(&wgpu::BufferDescriptor {
+			label: None,
+			size: size_of::<LookParams>() as u64,
+			usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+			mapped_at_creation: false,
+		});
+
+		let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+			label: None,
+			source: wgpu::ShaderSource::Wgsl(MESH_SHADER.into()),
+		});
+		let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+			label: None,
+			layout: None,
+			vertex: wgpu::VertexState {
+				module: &shader,
+				entry_point: None,
+				compilation_options: wgpu::PipelineCompilationOptions::default(),
+				buffers: &[wgpu::VertexBufferLayout {
+					array_stride: size_of::<Vertex>() as u64,
+					step_mode: wgpu::VertexStepMode::Vertex,
+					attributes: &[
+						wgpu::VertexAttribute {
+							shader_location: 0,
+							offset: offset_of!(Vertex, position) as u64,
+							format: wgpu::VertexFormat::Float32x3,
+						},
+						wgpu::VertexAttribute {
+							shader_location: 1,
+							offset: offset_of!(Vertex, normal) as u64,
+							format: wgpu::VertexFormat::Float32x3,
+						},
+					],
+				}],
+			},
+			primitive: wgpu::PrimitiveState {
+				topology: wgpu::PrimitiveTopology::TriangleList,
+				// cull_mode: Some(wgpu::Face::Front),
+				..Default::default()
+			},
+			depth_stencil: Some(wgpu::DepthStencilState {
+				format: DEPTH_FORMAT,
+				depth_write_enabled: true,
+				depth_compare: wgpu::CompareFunction::LessEqual,
+				stencil: wgpu::StencilState::default(),
+				bias: wgpu::DepthBiasState::default(),
+			}),
+			multisample: wgpu::MultisampleState {
+				count: 1,
+				mask: !0,
+				alpha_to_coverage_enabled: false,
+			},
+			fragment: Some(wgpu::FragmentState {
+				module: &shader,
+				entry_point: None,
+				compilation_options: wgpu::PipelineCompilationOptions::default(),
+				targets: &[Some(wgpu::ColorTargetState {
+					format: OUTPUT_FORMAT,
+					blend: Some(wgpu::BlendState::REPLACE),
+					write_mask: wgpu::ColorWrites::ALL,
+				})],
+			}),
+			multiview: None,
+			cache: None,
+		});
+		let bindings = device.create_bind_group(&wgpu::BindGroupDescriptor {
+			label: None,
+			layout: &pipeline.get_bind_group_layout(0),
+			entries: &[wgpu::BindGroupEntry {
+				binding: 0,
+				resource: look_buf.as_entire_binding(),
+			}],
+		});
+		Self {
+			look_buf,
+			bindings,
+			pipeline,
+		}
+	}
+
+	pub fn set_look(&self, queue: &wgpu::Queue, look: LookParams) {
+		queue.write_buffer(&self.look_buf, 0, bytes_of(&look));
+	}
+
+	pub fn render<'a>(
+		&self,
+		pass: &mut wgpu::RenderPass,
+		meshes: impl IntoIterator<Item = &'a Mesh>,
+	) {
+		pass.set_pipeline(&self.pipeline);
+		pass.set_bind_group(0, &self.bindings, &[]);
+		for mesh in meshes {
+			pass.set_vertex_buffer(0, mesh.vertex_buffer.slice(..));
+			pass.draw(0..mesh.vertex_count, 0..1);
+		}
+	}
+}

ui/src/api.hxx

@@ -11,11 +11,25 @@ struct alignas(16) Vec4 {
 namespace ffi {
 struct Core;
 
+struct ShapeArgs {
+	std::uint32_t sides;
+	std::uint32_t layers_up;
+	std::uint32_t layers_down;
+	float base_diameter;
+	float height;
+};
+
 struct RedrawArgs {
+	ShapeArgs shape;
 	Vec4 background;
+	float camera_yaw;
+	float camera_pitch;
+	float light_yaw;
+	float light_pitch;
 };
 } // namespace ffi
 
+using ffi::ShapeArgs;
 using ffi::RedrawArgs;
 
 class MutCore {

ui/src/main_window.cxx

@@ -13,8 +13,20 @@ Hyperboloid::~Hyperboloid() = default;
 
 void Hyperboloid::updateView() {
 	const auto color = m_ui->inBackground->color();
-	RedrawArgs args{
+	const ShapeArgs shape {
+		.sides = (std::uint32_t)m_ui->sides->value(),
+		.layers_up = (std::uint32_t)m_ui->layersUp->value(),
+		.layers_down = (std::uint32_t)m_ui->layersDown->value(),
+		.base_diameter = (float)m_ui->dia->value(),
+		.height = (float)m_ui->height->value(),
+	};
+	const RedrawArgs args{
+		.shape = shape,
 		.background = { color.redF(), color.greenF(), color.blueF(), 1.00 },
+		.camera_yaw = qDegreesToRadians((float)m_ui->camYaw->value()),
+		.camera_pitch = qDegreesToRadians((float)m_ui->camPitch->value()),
+		.light_yaw = 0.0,
+		.light_pitch = qDegreesToRadians((float)m_ui->lightPitch->value()),
 	};
 	m_ui->viewport->setView(args);
 }

ui/src/main_window.ui

@@ -40,6 +40,223 @@
    </attribute>
    <widget class="QWidget" name="dockWidgetContents">
     <layout class="QVBoxLayout" name="verticalLayout_2">
+     <item>
+      <widget class="QGroupBox" name="groupBox">
+       <property name="title">
+        <string>Camera</string>
+       </property>
+       <layout class="QVBoxLayout" name="verticalLayout">
+        <item>
+         <widget class="QLabel" name="label_5">
+          <property name="text">
+           <string>Yaw</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSlider" name="camYaw">
+          <property name="minimum">
+           <number>-180</number>
+          </property>
+          <property name="maximum">
+           <number>180</number>
+          </property>
+          <property name="pageStep">
+           <number>15</number>
+          </property>
+          <property name="value">
+           <number>45</number>
+          </property>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="label_2">
+          <property name="text">
+           <string>Pitch</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSlider" name="camPitch">
+          <property name="minimum">
+           <number>-90</number>
+          </property>
+          <property name="maximum">
+           <number>90</number>
+          </property>
+          <property name="pageStep">
+           <number>15</number>
+          </property>
+          <property name="value">
+           <number>30</number>
+          </property>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </item>
+     <item>
+      <widget class="QGroupBox" name="groupBox_2">
+       <property name="title">
+        <string>Light</string>
+       </property>
+       <layout class="QVBoxLayout" name="verticalLayout_3">
+        <item>
+         <widget class="QLabel" name="label_3">
+          <property name="text">
+           <string>Pitch</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSlider" name="lightPitch">
+          <property name="minimum">
+           <number>-90</number>
+          </property>
+          <property name="maximum">
+           <number>90</number>
+          </property>
+          <property name="pageStep">
+           <number>15</number>
+          </property>
+          <property name="value">
+           <number>60</number>
+          </property>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </item>
+     <item>
+      <widget class="QGroupBox" name="groupBox_3">
+       <property name="title">
+        <string>Shape</string>
+       </property>
+       <layout class="QVBoxLayout" name="verticalLayout_4">
+        <item>
+         <widget class="QLabel" name="label_4">
+          <property name="text">
+           <string>Sides</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSpinBox" name="sides">
+          <property name="minimum">
+           <number>3</number>
+          </property>
+          <property name="maximum">
+           <number>120</number>
+          </property>
+          <property name="value">
+           <number>24</number>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="label_6">
+          <property name="text">
+           <string>Layers up</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSpinBox" name="layersUp">
+          <property name="maximum">
+           <number>11</number>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="label_7">
+          <property name="text">
+           <string>Layers down</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSpinBox" name="layersDown">
+          <property name="maximum">
+           <number>11</number>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </item>
+     <item>
+      <widget class="QGroupBox" name="groupBox_4">
+       <property name="title">
+        <string>Size</string>
+       </property>
+       <layout class="QVBoxLayout" name="verticalLayout_5">
+        <item>
+         <widget class="QLabel" name="label_8">
+          <property name="text">
+           <string>Base diameter</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QDoubleSpinBox" name="dia">
+          <property name="suffix">
+           <string> mm</string>
+          </property>
+          <property name="minimum">
+           <double>4.000000000000000</double>
+          </property>
+          <property name="maximum">
+           <double>100.000000000000000</double>
+          </property>
+          <property name="stepType">
+           <enum>QAbstractSpinBox::AdaptiveDecimalStepType</enum>
+          </property>
+          <property name="value">
+           <double>36.000000000000000</double>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="label_9">
+          <property name="text">
+           <string>Height</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QDoubleSpinBox" name="height">
+          <property name="suffix">
+           <string> mm</string>
+          </property>
+          <property name="minimum">
+           <double>4.000000000000000</double>
+          </property>
+          <property name="maximum">
+           <double>500.000000000000000</double>
+          </property>
+          <property name="value">
+           <double>120.000000000000000</double>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </item>
+     <item>
+      <widget class="QGroupBox" name="groupBox_5">
+       <property name="title">
+        <string>Appearance</string>
+       </property>
+       <layout class="QVBoxLayout" name="verticalLayout_6">
         <item>
          <widget class="QLabel" name="label">
           <property name="text">
@@ -51,13 +268,16 @@
          <widget class="KColorCombo" name="inBackground">
           <property name="color">
            <color>
-         <red>25</red>
+            <red>85</red>
-         <green>220</green>
+            <green>170</green>
-         <blue>0</blue>
+            <blue>255</blue>
            </color>
           </property>
          </widget>
         </item>
+       </layout>
+      </widget>
+     </item>
      <item>
       <spacer name="verticalSpacer">
        <property name="orientation">
@@ -97,8 +317,8 @@
    <slot>updateView()</slot>
    <hints>
     <hint type="sourcelabel">
-     <x>1531</x>
+     <x>1585</x>
-     <y>115</y>
+     <y>803</y>
     </hint>
     <hint type="destinationlabel">
      <x>799</x>
@@ -106,6 +326,134 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>camYaw</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1520</x>
+     <y>142</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1449</x>
+     <y>133</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>camPitch</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1550</x>
+     <y>192</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1447</x>
+     <y>198</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>lightPitch</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1565</x>
+     <y>286</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1445</x>
+     <y>265</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>sides</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1521</x>
+     <y>370</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1448</x>
+     <y>378</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>layersUp</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1490</x>
+     <y>436</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1446</x>
+     <y>441</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>layersDown</sender>
+   <signal>valueChanged(int)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1478</x>
+     <y>513</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1446</x>
+     <y>515</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>dia</sender>
+   <signal>valueChanged(double)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1472</x>
+     <y>611</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1446</x>
+     <y>629</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>height</sender>
+   <signal>valueChanged(double)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>updateView()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>1476</x>
+     <y>686</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>1446</x>
+     <y>686</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
  <slots>
   <slot>updateView()</slot>