re-org en App

lib/src/resources/vertex.rs

@@ -0,0 +1,45 @@
+//! # Vertex Module — CPU-Side Per-Attribute Tuple (GPU Contract)
+//!
+//! Defines `Vertex`, the CPU-side data layout that is sent to the GPU as vertex attribute buffers.
+//! The struct's field order and offsets must exactly match the shader input attributes defined in
+//! PipelineCache::build_pipeline() — any mismatch will corrupt GPU rendering output.
+//!
+//! ## Technical Points
+//! - `#[repr(C)]` ensures fields are laid out contiguously without Rust padding reordering, matching C ABI.
+//! - `bytemuck::Pod + bytemuck::Zeroable` enables safe `cast_slice()` conversion for GPU buffer uploads.
+//! - **Performance**: The 56-byte stride per vertex is the contract between CPU data and GPU shader inputs;
+//!   PipelineCache::build_pipeline() reads this layout to construct VertexBufferLayout attributes array.
+
+/// Per-vertex attribute tuple: position (3D), normal (3D), texture coordinate (2D), color (RGBA).
+/// Must match the vertex buffer layout in PipelineCache::build_pipeline() byte-for-byte.
+#[repr(C)]
+#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct Vertex {
+    /// XYZ coordinates of this vertex in world space. Offset: 0 bytes.
+    pub position: [f32; 3],
+    /// XYZ coordinates of the vertex normal. Offset: 12 bytes.
+    pub normal: [f32; 3],
+    /// UV texture coordinates. Offset: 24 bytes
+    pub uv: [f32; 2],
+    /// RGBA color values. Offset: 32 bytes.
+    pub color: [f32; 4],
+}
+
+impl Default for Vertex {
+    // Default values for stability
+    fn default() -> Self {
+        Self {
+            // Default position at center (0, 0)
+            position: [0.0, 0.0, 0.0],
+
+            // Normal pointing upward (standard for lighting calculations)
+            normal: [0.0, 1.0, 0.0],
+
+            // UV coordinates at the origin of the texture
+            uv: [0.0, 0.0],
+
+            // Opaque white color by default
+            color: [1.0, 1.0, 1.0, 1.0],
+        }
+    }
+}