adventureland/js/codes/contributions/draivins_calculate_move2.js

function calculate_move(map, cur_x, cur_y, target_x, target_y) {
    var going_down = cur_y < target_y;
    var going_right = cur_x < target_x;

    var x_lines = map.x_lines || [];
    var y_lines = map.y_lines || [];

    var min_x = min(cur_x, target_x);
    var max_x = max(cur_x, target_x);
    var min_y = min(cur_y, target_y);
    var max_y = max(cur_y, target_y);

    var dx = target_x - cur_x;
    var dy = target_y - cur_y;

    var dydx = dy / (dx + EPS);
    var dxdy = 1 / dydx;

    for (var i = 0; i < x_lines.length; i++) {
        var line = x_lines[i];
        var line_x = line[0];
        if (max_x < line_x || min_x > line_x || max_y < line[1] || min_y > line[2]) {
            continue;
        }

        var y_intersect = cur_y + (line_x - cur_x) * dydx;

        if (y_intersect < line[1] || y_intersect > line[2]) {
            continue;
        }

        if (going_down) {
            target_y = min(target_y, y_intersect);
            max_y = target_y;
        } else {
            target_y = max(target_y, y_intersect);
            min_y = target_y;
        }

        if (going_right) {
            target_x = min(target_x, line_x - 3);
            max_x = target_x;
        } else {
            target_x = max(target_x, line_x + 3);
            min_x = target_x;
        }
    }

    for (var i = 0; i < y_lines.length; i++) {
        var line = y_lines[i];
        var line_y = line[0];
        if (max_y < line_y || min_y > line_y || max_x < line[1] || min_x > line[2]) {
            continue;
        }

        var x_intersect = cur_x + (line_y - cur_y) * dxdy;

        if (x_intersect < line[1] || x_intersect > line[2]) {
            continue;
        }

        if (going_right) {
            target_x = min(target_x, x_intersect);
            max_x = target_x;
        } else {
            target_x = max(target_x, x_intersect);
            min_x = target_x;
        }

        if (going_down) {
            target_y = min(target_y, line_y - 3);
            max_y = target_y;
        } else {
            target_y = max(target_y, line_y + 7);
            min_y = target_y;
        }
    }

    return {
        x: target_x,
        y: target_y
    };
}