réorg doc

lib/examples/meshes/simple.rs

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+//! Minimal declarative workflow, no explicit WGPU handling in this file.
+//! `AppBuilder` creates the event loop, then `App::run` opens the window, builds the `Context`/`Renderer`
+//! and drives the update → render → present loop. In winit 0.30 the GPU only exists
+//! after `resumed`: that is why shader registration + mesh/material/entity creation live in
+//! the `AppHandler::setup` hook, called once the context is ready. The PipelineCache
+//! lives in the scene (`Scene::init_gpu`, called in `resumed`): go through `register_shader` +
+//! `add_material_shader` + `create_mesh` + `add_entity`, the material being bound to the mesh. The mesh
+//! is declared from a **`Geometry`**: per-vertex positions + colors
+//! for the unlit quad. The scene renders automatically: the default `render()` method calls
+//! `app.render_scene(frame.view())`.
+use wsg_lib::AppHandler;
+use wsg_lib::app::AppBuilder;
+use wsg_lib::resources::Geometry;
+use wsg_lib::utils::WsgError;
+
+struct MonQuad;
+
+impl AppHandler for MonQuad {
+    fn setup(&mut self, app: &mut wsg_lib::App) {
+        // Flat 2D example: the `standard` shader in **unlit** mode (options.x = 1) returns the vertex
+        // color as-is. Flat 2D is thus a special case of 3D — a single pipeline for all.
+        app.renderer_mut().set_unlit(true);
+        app.scene
+            .register_shader("standard", wsg_lib::utils::STANDARD_SHADER_PATH)
+            .unwrap();
+
+        let geometry = Geometry::new(vec![
+            [-0.5, 0.5, 0.0],  // top-left
+            [0.5, 0.5, 0.0],   // top-right
+            [0.5, -0.5, 0.0],  // bottom-right
+            [-0.5, -0.5, 0.0], // bottom-left
+        ])
+        .with_normals(vec![[0.0, 0.0, 1.0]; 4])
+        .with_colors(vec![
+            [1.0, 0.0, 0.0, 1.0], // top-left (red)
+            [0.0, 1.0, 0.0, 1.0], // top-right (green)
+            [0.0, 0.0, 1.0, 1.0], // bottom-right (blue)
+            [1.0, 1.0, 0.0, 1.0], // bottom-left (yellow)
+        ])
+        .with_indices(vec![0, 1, 2, 0, 2, 3]);
+
+        // Default material: `None` lets the Scene inject its `standard` at render time
+        // (`Scene::default_material`) — this exercises the default path.
+        app.scene.create_mesh("quad_mesh", geometry, None).unwrap();
+        app.scene.add_entity("quad", "quad_mesh").unwrap();
+    }
+}
+
+#[pollster::main]
+async fn main() -> Result<(), WsgError> {
+    let app = AppBuilder::new().title("WSG Simple").build().await?;
+    app.run(MonQuad)
+}