ripping up the example

src/light.rs

@@ -0,0 +1,49 @@
+use bytemuck::__core::ops::Range;
+use bytemuck::{Zeroable, Pod};
+
+struct Light {
+    pos: cgmath::Point3<f32>,
+    color: wgpu::Color,
+    fov: f32,
+    depth: Range<f32>,
+    target_view: wgpu::TextureView,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+struct LightRaw {
+    proj: [[f32; 4]; 4],
+    pos: [f32; 4],
+    color: [f32; 4],
+}
+
+unsafe impl Pod for LightRaw {}
+
+unsafe impl Zeroable for LightRaw {}
+
+impl Light {
+    fn to_raw(&self) -> LightRaw {
+        use cgmath::{Deg, EuclideanSpace, Matrix4, PerspectiveFov, Point3, Vector3};
+
+        let mx_view = Matrix4::look_at(self.pos, Point3::origin(), Vector3::unit_z());
+        let projection = PerspectiveFov {
+            fovy: Deg(self.fov).into(),
+            aspect: 1.0,
+            near: self.depth.start,
+            far: self.depth.end,
+        };
+        let mx_correction = framework::OPENGL_TO_WGPU_MATRIX;
+        let mx_view_proj =
+            mx_correction * cgmath::Matrix4::from(projection.to_perspective()) * mx_view;
+        LightRaw {
+            proj: *mx_view_proj.as_ref(),
+            pos: [self.pos.x, self.pos.y, self.pos.z, 1.0],
+            color: [
+                self.color.r as f32,
+                self.color.g as f32,
+                self.color.b as f32,
+                1.0,
+            ],
+        }
+    }
+}