re-org en App

lib/src/resources/material.rs

@@ -0,0 +1,42 @@
+//! # Material Module — Appearance Descriptor (shader_id → RenderPipeline)
+//!
+//! Defines `Material`, a lightweight appearance descriptor that pairs a shader identifier with
+//! a shared RenderPipeline. Materials are created via PipelineCache to ensure pipeline reuse—
+//! multiple materials referencing the same shader_id point to the identical compiled GPU pipeline.
+//!
+//! ## Architecture Notes (per ARCHI_APP.md)
+//! - **Identifiants**: Each Material is registered in Scene by string identifier, enabling dynamic access
+//!   during the render loop without borrow checker issues. The shader_id serves as the Handle<T> key.
+//! - **Phase de Déclaration**: Materials are instantiated once in the declarative phase before the render loop begins.
+
+use crate::pipeline::PipelineCache;
+use std::sync::Arc;
+
+/// Lightweight appearance descriptor: links a shader ID to a shared RenderPipeline.
+/// Does not own the pipeline; holds an Arc for zero-copy sharing across objects using the same shader.
+pub struct Material {
+    /// Unique shader identifier used to look up or create a compiled RenderPipeline in PipelineCache.
+    pub shader_id: String,
+    /// Shared reference to the compiled GPU render pipeline. Multiple Materials can share one through Arc cloning.
+    pub pipeline: Arc<wgpu::RenderPipeline>,
+}
+
+impl Material {
+    /// Creates a new Material by requesting the cache to provide (or create) its RenderPipeline.
+    /// Inputs: device (GPU command source for pipeline creation), format (surface texture format),
+    ///         shader_id (unique key into PipelineCache), cache (mutable ref for potential insertion).
+    /// Returns a Material holding the Arc-wrapped pipeline. Called at scene initialization time.
+    pub fn new(
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        shader_id: &str,
+        cache: &mut PipelineCache,
+    ) -> Self {
+        // Request pipeline from cache — returns cached instance if already exists, creates new otherwise
+        let pipeline = cache.get_or_create(device, format, shader_id);
+        Self {
+            shader_id: shader_id.to_string(),
+            pipeline,
+        }
+    }
+}