splinosaurus 0.2.2

flexible spline and surface library
Documentation 
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use crate::grid::Grid;
use crate::surfaces::UV;
use alloc::vec::Vec;
use core::ops::Index;

/// 2D grid of control points.
#[derive(Debug, Clone)]
pub struct ControlGrid<T> {
    degree: usize,
    points: Grid<T>,
    u_wrapping: bool,
    v_wrapping: bool,
}

impl<T> ControlGrid<T> {
    /// Construct a new control grid of `degree`.
    pub fn new(degree: usize, u_len: usize, points: Vec<T>) -> Self {
        Self {
            degree,
            points: Grid::new(u_len, points),
            u_wrapping: false,
            v_wrapping: false,
        }
    }

    /// Length in the u direction with wrapping included.
    pub fn u_len(&self) -> usize {
        if !self.u_wrapping {
            self.points.len()
        } else {
            self.points.len() + self.degree
        }
    }

    /// Length in the v direction with wrapping included.
    pub fn v_len(&self) -> usize {
        if !self.v_wrapping {
            self.points.height()
        } else {
            self.points.height() + self.degree
        }
    }

    /// The degree of the curve.
    pub fn degree(&self) -> usize {
        self.degree
    }

    /// Set the degree of the curve.
    pub fn set_degree(&mut self, degree: usize) {
        self.degree = degree
    }

    /// Access all points.
    pub fn points(&self) -> &[T] {
        self.points.as_ref()
    }

    /// Mutate all points.
    pub fn points_mut(&mut self) -> &mut [T] {
        self.points.as_mut()
    }

    /// Grid wraps in the u direction.
    pub fn u_wrapping(&self) -> bool {
        self.u_wrapping
    }

    /// Set if the grid wraps in the u direction.
    pub fn set_u_wrapping(&mut self, u_wrapping: bool) {
        self.u_wrapping = u_wrapping
    }

    /// Grid wraps in the v direction.
    pub fn v_wrapping(&self) -> bool {
        self.v_wrapping
    }

    /// Set if the grid wraps in the v direction.
    pub fn set_v_wrapping(&mut self, v_wrapping: bool) {
        self.v_wrapping = v_wrapping
    }
}

impl<T> Index<UV<usize>> for ControlGrid<T> {
    type Output = T;

    fn index(&self, (u, v): UV<usize>) -> &Self::Output {
        let u = if self.u_wrapping {
            u % self.points.len()
        } else {
            u
        };
        let v = if self.v_wrapping {
            v % self.points.height()
        } else {
            v
        };

        &self.points[(u, v)]
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloc::vec;
    use nalgebra::Vector1;

    #[test]
    pub fn it_has_lengths() {
        let cg = ControlGrid::new(0, 2, vec![Vector1::new(0), Vector1::new(0)]);

        assert_eq!(2, cg.u_len());
        assert_eq!(1, cg.v_len());
    }

    #[test]
    pub fn it_indexes() {
        let cg = ControlGrid::new(
            0,
            2,
            vec![
                Vector1::new(0),
                Vector1::new(1),
                Vector1::new(2),
                Vector1::new(3),
            ],
        );

        assert_eq!(Vector1::new(0), cg[(0, 0)]);
        assert_eq!(Vector1::new(1), cg[(1, 0)]);
        assert_eq!(Vector1::new(2), cg[(0, 1)]);
        assert_eq!(Vector1::new(3), cg[(1, 1)]);
    }

    #[test]
    pub fn it_wraps() {
        let mut cg = ControlGrid::new(
            0,
            2,
            vec![
                //
                Vector1::new(0),
                Vector1::new(1),
                //
                Vector1::new(2),
                Vector1::new(3),
            ],
        );
        cg.set_u_wrapping(true);
        cg.set_v_wrapping(true);

        assert_eq!(Vector1::new(0), cg[(2, 0)]);
        assert_eq!(Vector1::new(0), cg[(0, 2)]);
        assert_eq!(Vector1::new(0), cg[(2, 2)]);

        assert_eq!(Vector1::new(1), cg[(3, 0)]);
        assert_eq!(Vector1::new(2), cg[(0, 3)]);
        assert_eq!(Vector1::new(3), cg[(3, 3)]);
    }
}