/// @param _x1
/// @param _y1
/// @param _x2
/// @param _y2
/// @param grid
/// @param dist = 0;
/// return true/false

var _x1 = argument[0], _y1 = argument[1], _x2 = argument[2], _y2 = argument[3], grid = argument[4];
var dist = argument_count > 5 ? argument[5] : 0;;

if (dist and dist < point_distance(_x1, _y1, _x2, _y2)) {
    var dir = point_direction(_x1, _y1, _x2, _y2);
    _x2 = _x1 + lengthdir_x(dist, dir);
    _y2 = _y1 + lengthdir_y(dist, dir);
}

var x1 = _x1 div GRID_CELL_WIDTH; // iso_from_normal_x(_x1, _y1);
var y1 = _y1 div GRID_CELL_HEIGHT; // iso_from_normal_y(_x1, _y1);
var x2 = _x2 div GRID_CELL_WIDTH; // iso_from_normal_x(_x2, _y2);
var y2 = _y2 div GRID_CELL_HEIGHT; // iso_from_normal_y(_x2, _y2);

// if (floor(x1) == floor(x2) or floor(y1) == floor(y2) or abs(floor(x1) - floor(x2)) == abs(floor(y1) - floor(y2))) {
//     return collision_line_grid_2(floor(x1), floor(y1), floor(x2), floor(y2), grid);
// }

if (grid[# floor(x1), floor(y1)] < 0) {
    return true;
}


if (grid[# floor(x2), floor(y2)] < 0) {
    return true;
}

var k = (y2 - y1) / (x2 - x1);
var b = y1 - k * x1;

var xs = min(x1, x2);
var xe = max(x1, x2);
for (var xx = ceil(xs); xx <= floor(xe); xx++) {
    if (grid[# floor(xx) - (y2 < y1), floor(k * xx + b)] < 0) {
        return true;
    }
}

var ys = min(y1, y2);
var ye = max(y1, y2);
for (var yy = ceil(ys); yy <= floor(ye); yy++) {
    if (grid[# floor((yy - b) / k), floor(yy) - (x2 < x1)] < 0) {
        return true;
    }
}

return false;