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// Projected-decal schema.
use crate::{AssetId, TextureHandle, de_opt_texture_handle};
/// A projected texture stamped onto whatever scene geometry sits inside the
/// decal's oriented box.
///
/// The decal is a box volume positioned by `position`/`rotation_deg`/`size` in
/// world space. The texture is projected down the box's local +Y axis onto the
/// local X-Z plane and stamped onto the surfaces inside the box; anything
/// outside the box is unaffected. Surfaces near the box's top and bottom faces
/// fade out so the stamp doesn't show a hard edge on a curved surface.
///
/// The defaults orient the decal as a ground stamp: a flat 1×1 m square laid on
/// the world X-Z plane, projecting down from +Y. To stamp a wall, rotate so
/// local +Y points into the surface (e.g. `rotation_deg:[0,0,90]` for a +X
/// wall).
///
/// Decals blend over the lit image without affecting depth, so they layer on
/// top of the surfaces they stamp.
///
/// ```rust
/// # use concinnity_asset::Decal;
/// Decal {
/// position: [2.0, 0.01, -1.5],
/// size: [1.5, 0.5, 1.5],
/// ..Default::default()
/// };
/// ```
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
#[serde(default)]
pub struct Decal {
/// Asset identity; injected via `inject_name`. Not part of `args`.
#[serde(skip)]
pub asset_id: AssetId,
/// The [Texture](#texture) asset projected onto the scene.
#[serde(deserialize_with = "de_opt_texture_handle")]
pub texture: Option<TextureHandle>,
/// World-space position of the decal box's centre.
pub position: [f32; 3],
/// Euler rotation in degrees [pitch, yaw, roll], YXZ order, same as
/// [Prop](#prop).
pub rotation_deg: [f32; 3],
/// Local-space box extents. Local +Y is the projection axis; the texture
/// is sampled on the local X-Z plane. A non-positive component disables
/// the decal.
pub size: [f32; 3],
/// Linear-space RGBA tint multiplied with the sampled texture. The alpha
/// channel scales the final blend, so `[1,1,1,0]` hides the decal.
pub tint: [f32; 4],
/// When false the decal is skipped each frame.
pub visible: bool,
}
impl Default for Decal {
fn default() -> Self {
Self {
asset_id: AssetId::default(),
texture: None,
position: [0.0, 0.0, 0.0],
rotation_deg: [0.0, 0.0, 0.0],
size: [1.0, 1.0, 1.0],
tint: [1.0, 1.0, 1.0, 1.0],
visible: true,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn a_blank_decal_is_a_visible_untinted_ground_stamp() {
let d = Decal::default();
assert_eq!(d.rotation_deg, [0.0, 0.0, 0.0]);
assert_eq!(d.size, [1.0, 1.0, 1.0]);
// An identity tint leaves the sampled texture alone; alpha 1 keeps it
// fully blended.
assert_eq!(d.tint, [1.0, 1.0, 1.0, 1.0]);
assert!(d.visible);
assert!(d.texture.is_none());
}
#[test]
fn a_wall_stamp_parses_and_round_trips_through_postcard() {
crate::test_support::install_resolvers();
let d: Decal = serde_json::from_str(
r#"{"texture":"tex_bullet","position":[3,1.6,-2],"rotation_deg":[0,0,90],
"size":[0.4,0.2,0.4],"tint":[1,1,1,0.5],"visible":false}"#,
)
.unwrap();
assert_eq!(d.texture, Some(TextureHandle(10)));
assert_eq!(d.rotation_deg, [0.0, 0.0, 90.0]);
assert!(!d.visible);
let bytes = postcard::to_allocvec(&d).unwrap();
let back: Decal = postcard::from_bytes(&bytes).unwrap();
assert_eq!(back.texture, Some(TextureHandle(10)));
assert_eq!(back.position, [3.0, 1.6, -2.0]);
assert_eq!(back.size, [0.4, 0.2, 0.4]);
assert_eq!(back.tint, [1.0, 1.0, 1.0, 0.5]);
assert_eq!(back.asset_id, AssetId::default());
}
}