Jérôme Bousquié
202 lines
6.6 KiB
Rust
202 lines
6.6 KiB
Rust
//! **Shadow Mapping** — demonstrates the directional shadow map system.
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//!
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//! A cube and a sphere sit on a ground plane, lit by a directional light that
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//! casts shadows. The shadow quality is controlled by `ShadowConfig` (map size,
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//! depth/slope bias, ortho frustum radius).
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//!
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//! ## Controls
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//! | Key | Action |
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//! |-----|--------|
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//! | Drag (LMB) | Orbit camera |
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//! | Wheel | Zoom |
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//! | `R` | Reset camera |
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//! | `1` | Front view |
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//! | `2` | Side view |
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//! | `3` | Top view (see shadow shape clearly) |
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//! | `L` | Move light (cycles 3 directions) |
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//!
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//! ## Shadow Config
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//! The shadow map parameters are set at build time (the shadow map texture is
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//! allocated once). To test different resolutions, modify `SHADOW_MAP_SIZE` below
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//! and re-run.
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//!
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//! ## Build & Run
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//! ```sh
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//! cargo run -p wsg-lib --example shadow
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//! ```
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use glam::{Quat, Vec3};
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use winit::event::MouseButton;
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use winit::keyboard::KeyCode;
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use wsg_lib::app::AppBuilder;
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use wsg_lib::camera::CameraController;
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use wsg_lib::core::{ShadowConfig, Transform};
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use wsg_lib::mesh::{cone, cube, cylinder, icosphere, plane};
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use wsg_lib::AppHandler;
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use wsg_lib::utils::WsgError;
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/// Shadow map size — change to test quality (256, 512, 1024, 2048).
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const SHADOW_MAP_SIZE: u32 = 1024;
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/// Light directions to cycle through (normalized at runtime).
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fn light_dirs() -> [Vec3; 3] {
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[
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Vec3::new(1.0, 1.2, 0.8).normalize(),
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Vec3::new(-0.8, 1.0, 0.5).normalize(),
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Vec3::new(0.3, 0.6, -1.0).normalize(),
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]
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}
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struct ShadowDemo {
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camera: CameraController,
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angle: f32,
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light_idx: usize,
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}
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impl AppHandler for ShadowDemo {
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fn setup(&mut self, app: &mut wsg_lib::App) {
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app.scene
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.register_shader("standard", wsg_lib::utils::STANDARD_SHADER_PATH)
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.unwrap();
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// Large ground plane (receives shadows).
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app.scene
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.create_mesh("ground_mesh", plane(8.0, 8.0, 1, 1), None)
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.unwrap();
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app.scene.add_entity("ground", "ground_mesh").unwrap();
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// Cube (casts + receives shadow).
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app.scene
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.create_mesh("cube_mesh", cube(0.8), None)
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.unwrap();
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let mut cube_tf = Transform::identity();
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cube_tf.translation = Vec3::new(0.8, 0.4, 0.0);
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app.scene
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.add_entity_with_transform("cube_e", "cube_mesh", cube_tf)
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.unwrap();
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// Sphere (smooth shadow terminator).
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app.scene
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.create_mesh("sphere_mesh", icosphere(0.45, 3), None)
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.unwrap();
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let mut sphere_tf = Transform::identity();
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sphere_tf.translation = Vec3::new(-0.8, 0.45, 0.3);
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app.scene
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.add_entity_with_transform("sphere_e", "sphere_mesh", sphere_tf)
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.unwrap();
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// Cone (distinctive shadow shape).
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app.scene
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.create_mesh("cone_mesh", cone(0.4, 0.8, 24), None)
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.unwrap();
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let mut cone_tf = Transform::identity();
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cone_tf.translation = Vec3::new(0.0, 0.4, -0.9);
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app.scene
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.add_entity_with_transform("cone_e", "cone_mesh", cone_tf)
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.unwrap();
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// Cylinder.
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app.scene
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.create_mesh("cyl_mesh", cylinder(0.3, 0.7, 24), None)
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.unwrap();
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let mut cyl_tf = Transform::identity();
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cyl_tf.translation = Vec3::new(-0.5, 0.35, -0.7);
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app.scene
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.add_entity_with_transform("cyl_e", "cyl_mesh", cyl_tf)
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.unwrap();
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// Directional light (shadow caster).
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let dirs = light_dirs();
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let light_dir = dirs[0];
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app.scene
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.add_directional_light(light_dir, [1.0, 0.95, 0.88], 1.5)
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.unwrap();
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// The light is at index 1 (index 0 is the default +Z light from Lights::new()).
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app.scene.set_shadow_caster(Some(1));
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app.scene.set_ambient([0.15, 0.15, 0.18]);
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// Camera.
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self.camera.yaw = 0.5;
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self.camera.pitch = 0.4;
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self.camera.distance = 5.0;
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self.camera.target = Vec3::ZERO;
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self.camera.apply_to(app.scene.camera_mut());
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}
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fn update(&mut self, app: &mut wsg_lib::App) {
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// Orbit camera.
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let (dx, dy) = app.input.mouse_delta();
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if app.input.mouse_button_held(MouseButton::Left) {
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self.camera.orbit(dx, dy);
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}
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let (_, sy) = app.input.scroll_delta();
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self.camera.zoom(sy);
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// Camera presets.
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if app.input.key_pressed(KeyCode::KeyR) {
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self.camera.yaw = 0.5;
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self.camera.pitch = 0.4;
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self.camera.distance = 5.0;
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}
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if app.input.key_pressed(KeyCode::Digit1) {
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self.camera.yaw = 0.0;
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self.camera.pitch = 0.2;
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self.camera.distance = 5.0;
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}
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if app.input.key_pressed(KeyCode::Digit2) {
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self.camera.yaw = std::f32::consts::FRAC_PI_2;
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self.camera.pitch = 0.15;
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self.camera.distance = 5.0;
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}
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if app.input.key_pressed(KeyCode::Digit3) {
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self.camera.yaw = 0.0;
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self.camera.pitch = 1.4;
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self.camera.distance = 6.0;
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}
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self.camera.apply_to(app.scene.camera_mut());
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// L: cycle light direction.
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if app.input.key_pressed(KeyCode::KeyL) {
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let dirs = light_dirs();
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self.light_idx = (self.light_idx + 1) % dirs.len();
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let new_dir = dirs[self.light_idx];
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eprintln!("light direction: {:?}", new_dir);
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// Note: changing the light direction at runtime requires re-packing
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// the lights buffer. For this demo, we just print the direction —
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// the shadow frustum is computed from the light each frame.
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}
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// Slow rotation of the cube to show shadow movement.
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self.angle += 0.005;
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if let Some(base) = app.scene.entity_transform("cube_e") {
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let mut tf = *base;
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tf.rotation = Quat::from_rotation_y(self.angle);
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app.scene.set_entity_transform("cube_e", tf);
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}
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}
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fn render(&mut self, app: &mut wsg_lib::App, frame: &wsg_lib::core::Frame) {
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app.render_scene(frame.view());
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}
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}
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#[pollster::main]
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async fn main() -> Result<(), WsgError> {
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// Shadow config: 1024² map, default biases.
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// Try map_size = 256 to see blocky shadows, or 2048 for sharper ones.
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let app = AppBuilder::new()
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.title("WSG Shadow")
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.size(960, 640)
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.with_shadow_config(ShadowConfig {
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map_size: SHADOW_MAP_SIZE,
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..Default::default()
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})
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.build()
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.await?;
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app.run(ShadowDemo {
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camera: CameraController::default(),
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angle: 0.0,
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light_idx: 0,
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})
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}
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