[v0.21.3] InfiniteScrollMap offset issue

[Kiel97]

Hey, I need a little help figuring out this strange issue related to InfiniteScrollMap. I've been using The Purple Night as an reference but not I'm stuck here and I don't know what is causing it. What I expected was flawless scroll of map at the same y coordinate while incrementing x position and setting it to this map. I'm using v0.21.3 version of agb.

An issue visible on screen

How it is stored in VRAM

gfx/tile.png

main.rs

extern crate alloc;

mod level;

use agb::{
    display::{
        tiled::{
            InfiniteScrolledMap, RegularBackgroundSize
        }, Priority
    },
    include_background_gfx,
    input::{Button, ButtonController},
    fixnum::Vector2D,
    sound::mixer::Frequency
};
use alloc::boxed::Box;

include_background_gfx!(basic_tiles,
    basic => deduplicate "gfx/tiles.png",
);

#[agb::entry]
fn main(mut gba: agb::Gba) -> ! {
    use agb::display::tiled::PartialUpdateStatus;

    let vblank = agb::interrupt::VBlank::get();

    let (gfx, mut vram) = gba.display.video.tiled0();
    let mut mixer = gba.mixer.mixer(Frequency::Hz18157);
    mixer.enable();

    let mut button_controller = ButtonController::new();

    let tileset = &basic_tiles::basic.tiles;
    vram.set_background_palettes(basic_tiles::PALETTES);

    let mut bg = InfiniteScrolledMap::new(
        gfx.background(
            Priority::P3,
            RegularBackgroundSize::Background32x32,
            tileset.format(),
        ),
        Box::new(|pos| {(
                &basic_tiles::basic.tiles,
                basic_tiles::basic.tile_settings[
                    *level::ARRAY.get(
                        (pos.x + level::WIDTH * pos.y) as usize
                    ).unwrap_or(&0)
                ],
            )
        }),
    );

    let mut between_updates = || {
        mixer.frame();
        vblank.wait_for_vblank();
    };

    let mut camera_position = Vector2D::new(0, 0);

    bg.init(&mut vram, camera_position, &mut between_updates);
    bg.commit(&mut vram);
    bg.set_visible(true);
    
    loop {
        button_controller.update();

        if button_controller.is_just_pressed(Button::RIGHT) {
            camera_position.x += 8
        }
        if button_controller.is_just_pressed(Button::LEFT) {
            camera_position.x -= 8
        }
        if button_controller.is_just_pressed(Button::UP) {
            camera_position.y -= 8
        }
        if button_controller.is_just_pressed(Button::DOWN) {
            camera_position.y += 8
        }

        while let PartialUpdateStatus::Continue = bg.set_pos(&mut vram, camera_position) {
            mixer.frame();
            vblank.wait_for_vblank();
        }
        bg.commit(&mut vram);
    }
}

level.rs

pub const WIDTH: i32 = 32;
pub const ARRAY: &[usize] = &[
     4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 0, 0,
    10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 4, 5, 4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11,10,11,10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 0, 0,
    10,11, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9,10,11, 0, 0,
     4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 0, 0,
    10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11,10,11, 0, 0,
];

[corwinkuiper]

• You need to modulo the x with the width for it to wrap. I like rem_euclid for this purpose. Modulo is quite expensive on thumb even if the value is known at compile time, that is unless the value is a power of 2.

  basic_tiles::basic.tile_settings[
      *level::ARRAY.get(
          (pos.x.rem_euclid(level::WIDTH)+ level::WIDTH * pos.y) as usize
      ).unwrap_or(&0)
  ],

• If you're not expecting the pink between the maps, that's because you are referring to tile 0 in the level array.

Hope that helps!

[Kiel97]

Thanks! That's what I wanted. rem_euclid works like a charm.

About pink between the maps - Tile 0 is a fully transparent tile so I expected all tiles 0 to be pink since it's default transparency color in include_background_gfx! macro