glam 0.34.1

A simple and fast 3D math library for games and graphics
Documentation 
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#[macro_use]
mod support;

macro_rules! impl_float_tests {
    ($t:ident) => {
        glam_test!(test_lerp, {
            let a = 0.;
            let b = 10.;
            assert_eq!($t::lerp(a, b, 0.), a);
            assert_eq!($t::lerp(a, b, 0.5), 5.);
            assert_eq!($t::lerp(a, b, 1.), b);
            assert_eq!($t::lerp(a, a, 0.), a);
            assert_eq!($t::lerp(a, a, 1.), a);
        });

        glam_test!(test_lerp_big_difference, {
            // `lerp` uses the form `self * (1 - s) + rhs * s`, which guarantees `rhs` at `s == 1`
            // even when the inputs differ greatly in magnitude.
            let a = -16.0e30;
            let b = 16.0;
            assert_eq!($t::lerp(a, b, 0.), a);
            assert_eq!($t::lerp(a, b, 1.), b);
        });

        glam_test!(test_lerp_monotonic, {
            let a = -1.;
            let b = 1.;
            assert_eq!($t::lerp_monotonic(a, b, 0.), a);
            assert_eq!($t::lerp_monotonic(a, b, 0.5), 0.);
            assert_eq!($t::lerp_monotonic(a, b, 1.), b);
            // Extrapolates linearly outside `[0, 1]`.
            assert_eq!($t::lerp_monotonic(a, b, -1.), -3.);
            assert_eq!($t::lerp_monotonic(a, b, 2.), 3.);

            // Equal values are preserved exactly, which `lerp` does not guarantee.
            let c = 0.1;
            assert_eq!($t::lerp_monotonic(c, c, 0.25), c);

            // Documented tradeoff: `rhs - self` overflows for opposite-sign extremes, so even the
            // endpoints are not exact in that case. `lerp` is unaffected.
            let max = $t::MAX;
            assert!($t::lerp_monotonic(max, -max, 0.5).is_infinite());
            assert!($t::lerp_monotonic(max, -max, 0.).is_nan());
        });

        glam_test!(test_inverse_lerp, {
            let a = 0.;
            let b = 10.;
            assert_eq!($t::inverse_lerp(a, b, 0.), 0.);
            assert_eq!($t::inverse_lerp(a, b, 5.), 0.5);
            assert_eq!($t::inverse_lerp(a, b, 10.), 1.);
            assert_eq!($t::inverse_lerp(a, b, 15.), 1.5);
            assert!($t::inverse_lerp(a, a, 0.).is_nan());
            assert!($t::inverse_lerp(a, a, 1.).is_infinite());
        });

        glam_test!(test_smoothstep, {
            assert_eq!((-1. as $t).smoothstep(0., 1.), 0.);
            assert_eq!((0. as $t).smoothstep(0., 1.), 0.);
            assert_eq!((0.5 as $t).smoothstep(0., 1.), 0.5);
            assert_eq!((1. as $t).smoothstep(0., 1.), 1.);
            assert_eq!((2. as $t).smoothstep(0., 1.), 1.);
        });

        glam_test!(test_remap, {
            assert_eq!($t::remap(0., 0., 2., 0., 20.), 0.);
            assert_eq!($t::remap(1., 0., 2., 0., 20.), 10.);
            assert_eq!($t::remap(2., 0., 2., 0., 20.), 20.);
            assert_eq!($t::remap(-5., -10., 30., 60., 20.), 55.);
            // Pins the precise `lerp`: `lerp_monotonic` returns 0 here.
            assert_eq!(20., $t::remap(2., 0., 2., -1e30, 20.));
            // When one of the input ranges is degenerate `inverse_lerp` is infinite or NaN, which
            // `lerp` (using the precise form) propagates as NaN.
            assert!($t::remap(0., 0., 0., 0., 1.).is_nan());
            assert!($t::remap(1., 0., 0., 0., 1.).is_nan());
        });

        glam_test!(test_fract_gl, {
            assert_approx_eq!(1.35.fract_gl(), 0.35);
            assert_approx_eq!((-1.5).fract_gl(), 0.5);
            assert_approx_eq!((-2000000.123).fract_gl(), 0.877, 0.002);
            assert_approx_eq!(1000000.123.fract_gl(), 0.123, 0.002);
        });

        glam_test!(test_move_towards, {
            assert_eq!($t::move_towards(-1., 1., 0.), -1.);
            assert_eq!($t::move_towards(-1., 1., 1.), 0.);
            assert_eq!($t::move_towards(-1., 1., 2.), 1.);
            assert_eq!($t::move_towards(-1., 1., 3.), 1.);
            assert_eq!($t::move_towards(1., -1., 1.), 0.);
            assert_eq!($t::move_towards(1., -1., 3.), -1.);
            assert_eq!($t::move_towards(1., 1., 1.), 1.);
        });
    };
}

mod float32 {
    use glam::FloatExt;

    impl_float_tests!(f32);
}

#[cfg(feature = "f64")]
mod float64 {
    use glam::FloatExt;

    impl_float_tests!(f64);
}