zig-learn/movement.zig

const term = @import("term.zig");
const Winsize = term.Winsize;
const primitive = @import("primitives.zig");
const Point = primitive.Point;

pub fn mv_axis_border_bounce(w: Winsize, point: *Point, axis: u8) void {
    var cor = &point.x;
    var dir = &point.direction.x;
    var upper = w.ws_col;

    switch (axis) {
        'x' => {
            cor = &point.x;
            upper = w.ws_col;
            dir = &point.direction.x;
        },
        'y' => {
            cor = &point.y;
            upper = w.ws_row;
            dir = &point.direction.y;
        },
        'X' => {
            cor = &point.x;
            upper = w.ws_col;
            dir = &point.direction.x;
            dir.* *= -1;
        },
        'Y' => {
            cor = &point.y;
            upper = w.ws_row;
            dir = &point.direction.y;
            dir.* *= -1;
        },
        else => {},
    }

    //if (cor.* < upper and cor.* > 0) {
    cor.* += dir.*;
    //  }
    if (cor.* >= upper or cor.* <= 0) {
        dir.* *= -1;
        cor.* += dir.*;
    }
}