feat: attempt to implement math library

Adds many files, but the next thing is to implement the MeshRegistry properly.

src/gpu/instance.rs

@@ -0,0 +1,29 @@
+use vulkano::buffer::BufferContents;
+use vulkano::pipeline::graphics::vertex_input::Vertex;
+use crate::common::instance::MeshInstance;
+
+/// A transformation matrix for a mesh that can be passed into the shaders.
+#[derive(BufferContents, Vertex)]
+#[repr(C)]
+pub struct GpuInstance {
+    #[format(R32G32B32A32_SFLOAT)]
+    pub transform_col1: [f32; 4],
+    #[format(R32G32B32A32_SFLOAT)]
+    pub transform_col2: [f32; 4],
+    #[format(R32G32B32A32_SFLOAT)]
+    pub transform_col3: [f32; 4],
+    #[format(R32G32B32A32_SFLOAT)]
+    pub transform_col4: [f32; 4],
+}
+
+impl Into<GpuInstance> for MeshInstance {
+    fn into(self) -> GpuInstance {
+        let m = self.transform_matrix();
+        GpuInstance {
+            transform_col1: m.column(0).into(),
+            transform_col2: m.column(1).into(),
+            transform_col3: m.column(2).into(),
+            transform_col4: m.column(3).into(),
+        }
+    }
+}