Hands-on Rust: fence post render bug in the dungeon crawler

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1

The player appears to go off-screen anywhere on the left edge (column 0) or top edge (row 0) of the dungeon. I’ve tried debugging, but haven’t been able to figure out a fix. I even happens when running the game from the sample code.

2

Does it do that when you run the downloadable source code version? I’ve not been able to exit the map to the north/top or west/left on the build I have here.

I’d double check that your Map’s in_bounds implementations are correct (they changed a little after the first beta). Map should implement:

impl Map {
    pub fn in_bounds(&self, point : Point) -> bool {
        point.x >= 0 && point.x < SCREEN_WIDTH && point.y >= 0 && point.y < SCREEN_HEIGHT
    }

    fn valid_exit(&self, loc: Point, delta: Point) -> Option<usize> {
        let destination = loc + delta;
        if self.in_bounds(destination) {
            if self.can_enter_tile(destination) {
                let idx = self.point2d_to_index(destination);
                Some(idx)
            } else {
                None
            }
        } else {
            None
        }
    }

It should also implement the Algorithm2D trait:

impl Algorithm2D for Map {

    fn dimensions(&self) -> Point {

        Point::new(SCREEN_WIDTH, SCREEN_HEIGHT)

    }

    fn in_bounds(&self, point: Point) -> bool {

        self.in_bounds(point)

    }

}

The movement system checks can_enter_tile, which should check both in_bounds and tile contents from the Map.

Let me know if you have any luck - I hope that helps!

3

It looks like I had missed the Algorithm2D implementation of in_bounds. It works after adding that. The downloadable source I had from 12/31 didn’t have that function, but the latest does. I guess that’s part of the risk of following along with beta books. :smiley:

Thank you for responding. I’m enjoying the book.

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