gemath 0.1.0

Type-safe game math with type-level units/spaces, typed angles, and explicit fallible ops (plus optional geometry/collision).
Documentation 
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#![cfg(all(feature = "rect2", feature = "mat4"))]

use gemath::*;
use crate::vec2::*;
use crate::rect2::*;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_rect2_new() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(1.0, 2.0), Vec2::new(3.0, 4.0));
        assert_eq!(r.pos, Vec2::new(1.0, 2.0));
        assert_eq!(r.dim, Vec2::new(3.0, 4.0));
    }

    #[test]
    fn test_rect2_default() {
        let r: Rect2 = Default::default();
        assert_eq!(r.pos, Vec2::ZERO);
        assert_eq!(r.dim, Vec2::ZERO);
    }

    #[test]
    fn test_rect2_from_slice() {
        let r: Rect2<(),()> = Rect2::from_slice(&[1.0, 2.0, 3.0, 4.0]);
        assert_eq!(r.pos, Vec2::new(1.0, 2.0));
        assert_eq!(r.dim, Vec2::new(3.0, 4.0));
    }

    #[test]
    fn test_rect2_contains_point_coords() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(3.0, 3.0));
        // Point inside
        assert!(r.contains_point_coords(2.0, 2.0));
        // Point on min_edge (inclusive)
        assert!(r.contains_point_coords(1.0, 1.0));
        assert!(r.contains_point_coords(1.0, 2.5));
        assert!(r.contains_point_coords(2.5, 1.0));
        // Point on max_edge (exclusive)
        assert!(!r.contains_point_coords(4.0, 4.0));
        assert!(!r.contains_point_coords(1.0, 4.0));
        assert!(!r.contains_point_coords(4.0, 1.0));
        // Point outside
        assert!(!r.contains_point_coords(0.0, 0.0));
        assert!(!r.contains_point_coords(5.0, 5.0));

        // Test with negative dimensions (should normalize)
        let r_neg_dim: Rect2<(),()> = Rect2::new(Vec2::new(4.0, 4.0), Vec2::new(-3.0, -3.0));
        assert!(r_neg_dim.contains_point_coords(2.0, 2.0));
        assert!(r_neg_dim.contains_point_coords(1.0, 1.0)); // min edge
        assert!(!r_neg_dim.contains_point_coords(4.0, 4.0)); // max edge
    }

    #[test]
    fn test_rect2_contains_point() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(3.0, 3.0));
        assert!(r.contains_point(Vec2::new(2.0, 2.0)));
        assert!(!r.contains_point(Vec2::new(5.0, 5.0)));
    }

    #[test]
    fn test_rect2_intersects_and_intersection() {
        let r1: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(2.0, 2.0));
        let r2: Rect2<(),()> = Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(2.0, 2.0));
        let r3: Rect2<(),()> = Rect2::new(Vec2::new(3.0, 3.0), Vec2::new(1.0, 1.0));
        let r4: Rect2<(),()> = Rect2::new(Vec2::new(0.5, 0.5), Vec2::new(1.0, 1.0)); // r4 is inside r1

        // Intersection r1 and r2
        assert!(r1.intersects(&r2));
        assert_eq!(
            r1.intersection(&r2),
            Some(Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(1.0, 1.0)))
        );

        // No intersection r1 and r3
        assert!(!r1.intersects(&r3));
        assert_eq!(r1.intersection(&r3), None);

        // r4 is contained in r1
        assert!(r1.intersects(&r4));
        assert_eq!(r1.intersection(&r4), Some(r4));
        assert!(r4.intersects(&r1));
        assert_eq!(r4.intersection(&r1), Some(r4));

        // Touching edges (intersects returns Some, but with zero dimension for the touch axis)
        let r_touch_x = Rect2::new(Vec2::new(2.0, 0.0), Vec2::new(1.0, 2.0)); // r_touch_x touches r1 on x-axis
        assert!(!r1.intersects(&r_touch_x));
        // Intersection logic: x0 = max(0,2)=2, y0=max(0,0)=0, x1=min(2,3)=2, y1=min(2,2)=2. x0 < x1 (2<2) is false.
        assert_eq!(r1.intersection(&r_touch_x), None);

        let r_touch_y = Rect2::new(Vec2::new(0.0, 2.0), Vec2::new(2.0, 1.0)); // r_touch_y touches r1 on y-axis
        assert!(!r1.intersects(&r_touch_y));
        // Intersection logic: x0 = max(0,0)=0, y0=max(0,2)=2, x1=min(2,2)=2, y1=min(2,3)=2. y0 < y1 (2<2) is false.
        assert_eq!(r1.intersection(&r_touch_y), None);

        // Rectangles with negative dimensions
        let r_neg_dim1: Rect2<(),()> = Rect2::new(Vec2::new(2.0, 2.0), Vec2::new(-2.0, -2.0)); // Equivalent to r1 (0,0) (2,2)
        let r_neg_dim2: Rect2<(),()> = Rect2::new(Vec2::new(3.0, 3.0), Vec2::new(-2.0, -2.0)); // Equivalent to r2 (1,1) (2,2)
        assert!(r_neg_dim1.intersects(&r_neg_dim2));
        assert_eq!(
            r_neg_dim1.intersection(&r_neg_dim2),
            Some(Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(1.0, 1.0)))
        );

        // No overlap
        let r5: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(1.0, 1.0));
        let r6: Rect2<(),()> = Rect2::new(Vec2::new(1.0, 1.0), Vec2::new(1.0, 1.0)); // Touches at one point (1,1)
        assert!(!r5.intersects(&r6));
        assert_eq!(r5.intersection(&r6), None);
    }

    #[test]
    fn test_rect2_min_max_size() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(3.0, 2.0), Vec2::new(-2.0, 5.0));
        assert_eq!(r.min(), Vec2::new(1.0, 2.0));
        assert_eq!(r.max(), Vec2::new(3.0, 7.0));
        assert_eq!(r.size(), Vec2::new(2.0, 5.0));
    }

    #[test]
    fn test_rect2_area() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(3.0, 4.0));
        assert_eq!(r.area(), 12.0);
        let r_neg: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(-3.0, 4.0));
        assert_eq!(r_neg.area(), 12.0);
    }

    #[test]
    fn test_rect2_is_empty() {
        let r: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(0.0, 4.0));
        assert!(r.is_empty());
        let r2: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(3.0, 0.0));
        assert!(r2.is_empty());
        let r3: Rect2<(),()> = Rect2::new(Vec2::new(0.0, 0.0), Vec2::new(3.0, 4.0));
        assert!(!r3.is_empty());
    }

    #[test]
    fn test_rect2_from_min_max() {
        let min: Vec2<(),()> = Vec2::new(1.0, 2.0);
        let max: Vec2<(),()> = Vec2::new(4.0, 6.0);
        let r: Rect2<(),()> = Rect2::from_min_max(min, max);
        assert_eq!(r.min(), min);
        assert_eq!(r.max(), max);
    }

    #[test]
    fn test_rect2_expand_to_include() {
        let r: Rect2<(),()> = Rect2::from_min_max(Vec2::new(1.0, 2.0), Vec2::new(3.0, 4.0));
        let expanded: Rect2<(),()> = r.expand_to_include(Vec2::new(5.0, 0.0));
        assert_eq!(expanded.min(), Vec2::new(1.0, 0.0));
        assert_eq!(expanded.max(), Vec2::new(5.0, 4.0));
    }

    #[test]
    fn test_rect2_union() {
        let a: Rect2<(),()> = Rect2::from_min_max(Vec2::new(0.0, 0.0), Vec2::new(2.0, 2.0));
        let b: Rect2<(),()> = Rect2::from_min_max(Vec2::new(1.0, -1.0), Vec2::new(3.0, 1.0));
        let u: Rect2<(),()> = a.union(&b);
        assert_eq!(u.min(), Vec2::new(0.0, -1.0));
        assert_eq!(u.max(), Vec2::new(3.0, 2.0));
    }

    #[test]
    fn test_rect2_closest_point_and_distance() {
        let rect: Rect2<(),()> = Rect2::from_min_max(Vec2::new(1.0, 1.0), Vec2::new(3.0, 4.0));
        // Inside
        assert_eq!(rect.closest_point(Vec2::new(2.0, 2.0)), Vec2::new(2.0, 2.0));
        assert_eq!(rect.distance(Vec2::new(2.0, 2.0)), 0.0);
        // Outside
        assert_eq!(rect.closest_point(Vec2::new(0.0, 0.0)), Vec2::new(1.0, 1.0));
        assert!((rect.distance(Vec2::new(0.0, 0.0)) - (2.0_f32).sqrt()).abs() < 1e-6);
        assert_eq!(rect.closest_point(Vec2::new(4.0, 5.0)), Vec2::new(3.0, 4.0));
    }

    #[test]
    fn test_rect2_intersect_ray() {
        let rect: Rect2<(),()> = Rect2::from_min_max(Vec2::new(1.0, 1.0), Vec2::new(3.0, 4.0));
        // Ray from outside, hits
        let t = rect.intersect_ray(Vec2::new(0.0, 2.0), Vec2::new(1.0, 0.0));
        assert!(t.is_some() && (t.unwrap() - 1.0).abs() < 1e-6);
        // Ray from inside
        let t2 = rect.intersect_ray(Vec2::new(2.0, 2.0), Vec2::new(1.0, 0.0));
        assert!(t2.is_some() && (t2.unwrap() - 1.0).abs() < 1e-6);
        // Ray misses
        let t3 = rect.intersect_ray(Vec2::new(0.0, 0.0), Vec2::new(-1.0, 0.0));
        assert!(t3.is_none());
    }

    #[test]
    fn test_rect2_transform() {
        use crate::mat4::Mat4;
        let rect: Rect2<(),()> = Rect2::from_min_max(Vec2::new(1.0, 2.0), Vec2::new(3.0, 4.0));
        let m: Mat4 = Mat4::from_translation(crate::vec3::Vec3::new(10.0, 20.0, 0.0));
        let t: Rect2<(),()> = rect.transform(&m);
        assert_eq!(t.min(), Vec2::new(11.0, 22.0));
        assert_eq!(t.max(), Vec2::new(13.0, 24.0));
    }
}

// --- Compile-time (const) tests/examples for Rect2 ---
const _CONST_RECT0: Rect2f32 = Rect2f32::new(Vec2f32::new(1.0, 2.0), Vec2f32::new(3.0, 4.0));
const _CONST_RECT1: Rect2f32 = Rect2f32::new(Vec2f32::new(5.0, 6.0), Vec2f32::new(7.0, 8.0));
const _CONST_RECT_FROM_ARRAY: Rect2f32 = Rect2f32::from_array([1.0, 2.0, 3.0, 4.0]);
const _CONST_RECT_MIN: Vec2f32 = _CONST_RECT0.min();
const _CONST_RECT_MAX: Vec2f32 = _CONST_RECT0.max();
const _CONST_RECT_METERS: Rect2Meters = Rect2Meters::new(Vec2Meters::new(1.0, 2.0), Vec2Meters::new(3.0, 4.0));
const _CONST_RECT_WORLD: Rect2World = Rect2World::new(Vec2World::new(1.0, 2.0), Vec2World::new(3.0, 4.0));

const _: () = {
    // Compile-time assertions for const-everything
    assert!(_CONST_RECT0.pos.x == 1.0 && _CONST_RECT0.pos.y == 2.0);
    assert!(_CONST_RECT0.dim.x == 3.0 && _CONST_RECT0.dim.y == 4.0);
    assert!(_CONST_RECT_FROM_ARRAY.pos.x == 1.0 && _CONST_RECT_FROM_ARRAY.pos.y == 2.0);
    assert!(_CONST_RECT_FROM_ARRAY.dim.x == 3.0 && _CONST_RECT_FROM_ARRAY.dim.y == 4.0);
    assert!(_CONST_RECT_MIN.x == 1.0 && _CONST_RECT_MIN.y == 2.0);
    assert!(_CONST_RECT_MAX.x == 4.0 && _CONST_RECT_MAX.y == 6.0);
};

// Compile-time type safety: the following lines would fail to compile if uncommented
// const _FAIL: Rect2Meters = Rect2Pixels::new(Vec2Pixels::new(1.0, 2.0), Vec2Pixels::new(3.0, 4.0)); // error: mismatched types
// const _FAIL2: Rect2World = Rect2Local::new(Vec2Local::new(1.0, 2.0), Vec2Local::new(3.0, 4.0)); // error: mismatched types

#[test]
fn test_rect2_meters_to_pixels() {
    let meters: Rect2Meters = Rect2Meters::new(Vec2Meters::new(2.0, 3.0), Vec2Meters::new(4.0, 5.0));
    let pixels = meters.to_pixels(100.0);
    assert_eq!(pixels.pos, Vec2Pixels::new(200.0, 300.0));
    assert_eq!(pixels.dim, Vec2Pixels::new(400.0, 500.0));
}