Raymarching: set camera center to vec4 to avoid padding

Azkellas · Sep 29, 2023 · 101ba42 · 101ba42
1 parent 208b744
commit 101ba42
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Showing 4 changed files with 9 additions and 14 deletions.
diff --git a/lib/src/camera_control.rs b/lib/src/camera_control.rs
@@ -9,8 +9,8 @@ use crate::mouse_input::MouseState;
 #[repr(C)]
 #[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
 pub struct CameraLookAt {
-    // Object the camera is looking at.
-    pub center: [f32; 3],
+    // Object the camera is looking at. Use a vec4 to avoid padding.
+    pub center: [f32; 4],
     // Angle around the object on the horizontal plane, in radians.
     pub angle: f32,
     // Height between -1 and 1, 0 is flat, 1 is zenith, -1 is nadir
@@ -23,7 +23,7 @@ impl Default for CameraLookAt {
     fn default() -> Self {
         // See object in 0,0,0 from the front top left
         CameraLookAt {
-            center: [0.0, 0.0, 0.0],
+            center: [0.0, 0.0, 0.0, 0.0],
             angle: 2.0 * std::f32::consts::FRAC_PI_3,
             height: 0.3,
             distance: f32::sqrt(72.0),

diff --git a/lib/src/demo_raymarching.rs b/lib/src/demo_raymarching.rs
@@ -49,7 +49,7 @@ pub struct DemoRaymarchingSettings {
     pub camera: CameraLookAt,
     pub size: [f32; 2],
     pub elapsed: f32,   // elapsed take the speed into consideration
-    _padding: [f32; 3], // padding for alignment
+    _padding: [f32; 2], // padding for alignment
 }
 
 /// Demo raymarching program.
@@ -68,18 +68,13 @@ impl DemoRaymarchingSettings {
     pub fn new() -> Self {
         Self {
             camera: CameraLookAt::default(),
-            size: [0.0, 0.0],
             elapsed: 0.0,
-            _padding: [0.0; 3],
+            size: [0.0, 0.0],
+            _padding: [0.0; 2],
         }
     }
 
     pub fn get_size() -> u64 {
-        dbg!(
-            "DemoRaymarchingSettings::get_size",
-            std::mem::size_of::<Self>(),
-            (bytemuck::cast_slice(&[Self::new()]) as &[u8]).len()
-        );
         std::mem::size_of::<Self>() as _
     }
 }
@@ -215,7 +210,7 @@ impl DemoRaymarchingProgram {
         });
 
         let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
-            label: None,
+            label: Some("Raymarching Render Pipeline"),
             layout: Some(&layout),
             vertex: wgpu::VertexState {
                 module: &shader,

diff --git a/shaders/demo_raymarching/common.wgsl b/shaders/demo_raymarching/common.wgsl
@@ -1,6 +1,6 @@
 // Vertex shader
 struct Uniforms {
-  camera_center: vec3<f32>,
+  camera_center: vec4<f32>,
   camera_angle: f32,
   camera_height: f32,
   camera_distance: f32,

diff --git a/shaders/demo_raymarching/draw_3d.wgsl b/shaders/demo_raymarching/draw_3d.wgsl
@@ -105,7 +105,7 @@ fn sdf_3d(p: vec2<f32>) -> vec4<f32> {
     var time: f32 = uniforms.elapsed;
 
     // camera look at.
-    let look_at: vec3<f32> = uniforms.camera_center;
+    let look_at: vec3<f32> = uniforms.camera_center.xyz;
 
     // compute direction.
     var angle: vec3<f32> = vec3(cos(uniforms.camera_angle), 0.0, sin(uniforms.camera_angle));