Jérôme Bousquié
85 lines
3.3 KiB
Rust
85 lines
3.3 KiB
Rust
//! Test dedicated to **spot lights** (Step 13, Phase 4.2).
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//!
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//! In this example, **only** a spot light is on (the default directional light is
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//! removed via `clear_lights()`) and the ambient is deliberately **very low**. The cube therefore
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//! appears nearly black except where the spot's cone reaches it: you clearly see
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//!
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//! 1. a **directed beam** (not an omni halo like the point light),
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//! 2. a **smoothed edge** (penumbra) at the cone's limit,
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//! 3. the lighting that **follows the cube** as it rotates (the cone is fixed in world space).
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//!
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//! Run with: `cargo run -p wsg-lib --example spot_test`
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use glam::{Quat, Vec3};
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use wsg_lib::AppHandler;
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use wsg_lib::app::AppBuilder;
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use wsg_lib::math::cube;
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use wsg_lib::utils::WsgError;
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/// Test handler: cube rotating slowly on two axes, lit **only** by a spot.
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struct SpotTest {
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angle_x: f32,
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angle_y: f32,
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}
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impl AppHandler for SpotTest {
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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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app.scene.add_material_shader("mat", "standard").unwrap();
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app.scene
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.create_mesh("cube_mesh", cube(1.0), Some("mat"))
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.unwrap();
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app.scene.add_entity("cube", "cube_mesh").unwrap();
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// Remove the default directional light to isolate the spot.
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app.scene.clear_lights();
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// Near-zero ambient: the cube is black outside the beam, the cone stands out.
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app.scene.set_ambient([0.03, 0.03, 0.03]);
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// The spot is above/behind the camera, aimed at the origin (the cube).
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// World position (0, 2, 3), cone axis toward (0,0,0).
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let spot_pos = Vec3::new(0.0, 2.0, 3.0);
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let spot_dir = (Vec3::ZERO - spot_pos).normalize(); // points at the cube
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app.scene
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.add_spot_light(
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spot_pos,
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spot_dir,
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[1.0, 0.9, 0.6], // warm tint
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2.0, // intensity
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10.0, // attenuation radius (wide, the cube is at ~3.6)
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0.45, // half-angle (~26°) — wide enough to cover the cube
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)
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.unwrap();
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}
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fn update(&mut self, app: &mut wsg_lib::App) {
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// Slow rotation on two axes (X and Y): the cone is fixed in world space,
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// so a fixed region of the cube stays lit while the cube rotates.
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// The two axes let you see the beam's effect on the 6 faces without
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// a favored orientation (a Y rotation alone would leave the +Y/-Y faces fixed).
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self.angle_x += 0.007;
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self.angle_y += 0.011;
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let base = *app
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.scene
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.entity_transform("cube")
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.expect("cube entity present");
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let mut transform = base;
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// Y * X composition: the X axis rotates in the frame already oriented by Y,
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// which gives a precession motion (all vertices pass in front of
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// the cone in turn).
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transform.rotation =
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Quat::from_rotation_y(self.angle_y) * Quat::from_rotation_x(self.angle_x);
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app.scene.set_entity_transform("cube", transform);
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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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let app = AppBuilder::new().title("WSG Spot Test").build().await?;
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app.run(SpotTest {
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angle_x: 0.0,
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angle_y: 0.0,
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})
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}
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