Implementation of https://github.com/nesbox/TIC-80/wiki/Code-examples-and-snippets#draw-hanging-cable in Zig ⚡

draw_cable.zig

const math = @import("std").math;
const tic = @import("tic80.zig");

fn drawCable(p1: [2]f32, p2: [2]f32, max_sag: f32, color: i32) [2]f32 {
    const dx = p2[0] - p1[0];
    const dy = p2[1] - p1[1];
    const length = math.sqrt(dx * dx + dy * dy);
    const sag = @max(length / max_sag, max_sag);
    const midpoint: [2]f32 = .{
        (p1[0] + p2[0]) / 2,
        (p1[1] + p2[1]) / 2 + sag,
    };

    for (0..@as(usize, @intFromFloat(length))) |ux| {
        const x: f32 = @floatFromInt(ux);
        const y = math.sin(x / length * math.pi) * sag;

        const px = p1[0] + dx * x / length + 0.5;
        const py = p1[1] + dy * x / length + y + 0.5;

        const px_prev = p1[0] + dx * (x - 1) / length + 0.5;
        const py_prev = p1[1] + dy * (x - 1) / length + math.sin((x - 1) / length * math.pi) * sag + 0.5;

        tic.line(px_prev, py_prev, px, py, color);
    }

    return midpoint;
}