Tile Raycast

Raycasting in tiled worlds using the DDA algorithm. It is a very effective solution for tile-based worlds such as platformers or top-down games.

This implementation is inspired by:
https://lodev.org/cgtutor/raycasting.html
https://www.youtube.com/watch?v=NbSee-XM7WA

Installation

You can use Tiled Raycast in your own project by adding this project as a Defold library dependency. Open your game.project file and in the dependencies field under project, add:

https://github.com/selimanac/defold-tile-raycast/archive/refs/heads/master.zip

Examples

You can find vision cone and line of sight examples in this project.
Test it here: https://selimanac.github.io/defold-tile-raycast/

For v1: https://github.com/selimanac/defold-tile-raycast-platformer

Release Notes

v2

• BREAKING: Module name has been changed to tile_raycast
• Complete code refactoring
• Performance improvements
• New vision cone and line of sight examples

Use Cases(AI Generated)

Ray Casting in Games

2D Top-Down Roguelikes: Games like "The Binding of Isaac" and "Enter the Gungeon" use ray casting for line-of-sight calculations, bullet trajectory.

Wolfenstein 3D and similar pseudo-3D engines: The original Wolfenstein 3D used DDA-based ray casting to create a 3D-like environment from a 2D map.

Minecraft uses a variation for block targeting and lighting calculations.

Line-of-Sight Systems

Tactical games like "XCOM" and "Into the Breach" use DDA for determining visibility between units.

Stealth games for guard vision cones and detection systems.

Procedural Generation

Dungeon crawlers like "Rogue Legacy" use it for connecting rooms and ensuring paths are traversable.

Spelunky and similar games for procedural level interconnections.

Other Applications

Tower defense games for targeting and projectile calculations.

Strategy games for unit visibility and pathing calculations.

Battle royale games for circle/zone damage calculations across grid terrain.

API

tile_raycast.setup(tile_width, tile_heigh,tilemap_width,tilemap_height,tiles,target_tiles)

Initial setup for raycasting.

PARAMETERS

• tile_width (uint16_t) – Width of a single tile.
• tile_height (uint16_t) – Height of a single tile.
• tilemap_width (uint16_t) – Number of tiles horizontally in the tilemap.
• tilemap_height (uint16_t) – Number of tiles vertically in the tilemap.
• tiles (table - uint16_t ) – One-dimensional tile table generated from your tilemap or source data.
• target_tiles (table - uint16_t) – IDs of impassable tiles from your tilesource (e.g., walls, ground, etc.).

EXAMPLE

	
    local tiles = {
		4,2,2,2,0,2,2,2,2,2,
		2,2,2,2,0,2,2,2,2,2,
		2,2,2,2,0,2,2,2,2,2,
		2,2,1,2,2,2,2,2,2,2,
		2,2,2,2,2,2,2,2,2,2,
		1,2,1,2,2,2,1,1,1,1,
		1,1,1,2,2,2,1,1,1,1,
		1,1,1,2,1,2,1,3,1,1,
		1,1,1,1,2,1,1,1,4,1,
		1,1,1,2,2,2,2,1,1,3,
        1,1,1,1,1,1,1,1,1,1  
	}

    local tile_width = 32
    local tile_height = 32
    local target_tiles = {2, 3, 4}
    local tilemap_width = 10
    local tilemap_height = 11

    tile_raycast.setup(tile_width, tile_height, tilemap_width, tilemap_height, tiles, target_tiles)

---

tile_raycast.cast(ray_from_x,ray_from_y,ray_to_x, ray_to_y)

Performs a raycast on the tilemap. Returns only the first successful hit.

PARAMETERS

• ray_from_x (float) – Start position of the ray (X).
• ray_from_y (float) – Start position of the ray (Y).
• ray_to_x (float) – End position of the ray (X).
• ray_to_y (float) – End position of the ray (Y).

RETURN

• hit (boolean) – Whether a tile was hit.

• tile_x (uint16_t) – X position of the tile.

• tile_y (uint16_t) – Y position of the tile.

• array_id (uint16_t) – Index in the tilemap array.

• tile_id (uint16_t) – ID of the tile from the tilesource.

• intersection_x (float) – X coordinate of the ray intersection point.

• intersection_y (float) – Y coordinate of the ray intersection point.

• side (enum) – The side of the tile that was hit.

  tile_raycast.LEFT
  tile_raycast.RIGHT
  tile_raycast.TOP
  tile_raycast.BOTTOM

EXAMPLE

	
    local ray_from = go.get_position(ray_start_url)
    local ray_to = go.get_position(ray_end_url)

    local hit, tile_x, tile_y, array_id, tile_id, intersection_x, intersection_y, side = tile_raycast.cast(ray_from.x,ray_from.y, ray_to.x,ray_to.y)

     if hit then
        print("tile_x: " .. tile_x)
        print("tile_y: " .. tile_y)
        print("array_id " .. array_id)
        print("tile_id " .. tile_id)
        print("intersection_x " .. intersection_x)
        print("intersection_y " .. intersection_y)
        print("Side " .. side) 
    else
        print("No result found")
    end

---

tile_raycast.set_at(tile_x, tile_y, tile_id)

Sets a tile value in the map array at the specified coordinates.

PARAMETERS

• tile_x (uint16_t) – Tile X coordinate.
• tile_y (uint16_t) – Tile Y coordinate.
• tile_id (uint16_t) – Tile ID to set.

---

tile_raycast.get_at(tile_x, tile_y)

Returns the tile ID from the map array at the specified coordinates.

PARAMETERS

• tile_x (uint16_t) – Tile X coordinate.
• tile_y (uint16_t) – Tile Y coordinate.

RETURN

• tile_id (uint16_t) – Tile ID at the given coordinates.

---

tile_raycast.reset()

Clears all tile and tilemap data.