Abstract

Sketch-2-Tilemap generates a 3D video game level tilemap from an input sketch. This approach allows users to quickly design and prototype tiled levels by automating the manual work required to place tiles in a game engine. Sketch-2-Tilemap first generates an irregular quadrilateral grid from an input sketch where the bounds of the grid follow the contours of the sketch. Next, we implement an extended Wave Function Collapse (WFC) algorithm that
works on irregular grids to choose tile placements. Finally, tiles are transformed to the appropriate grid spaces using lattice deformation to generate an output game map. Faces on an irregular grid with mismatching orientations produce problems with WFC outputs. We show this through experimentation and propose a breadth-first orientation method to optimize face alignments for more varied output tilemaps.

Intro

Building large video games environments can be costly and time consuming. For many games, a large portion of this effort goes into creating art assets, which include 2D sprites or 3D models. In order to reduce costs, it is often important to create game art that is reusable and modular. Modular game assets can be fit together in new ways such that a much larger level can be synthesized from a limited number of different assets.

To maximize modularity, many games are built on a grid. Modular game assets are called tiles when they can be fit together on a grid. Grid-based games are most commonly built on a regular square grid, but there are many deviations from this such as triangular, hexagonal, and irregular grid-based games.

A level designer of a grid-based game may begin designing a map with a top-down sketch of the overall level layout. Once they are satisfied by their design, they build the level using a game engine which allows for the manual placement of modular tiles. This process can be time-consuming because it requires manual tile placement by the designer. This manual effort can slow down the production of a level and inhibit creativity during the prototyping process.

In this paper, we propose Sketch-2-Tilemap, a workflow that utilizes an extended version of the Wave Function Collapse algorithm which gives the user control over generated levels. The user specifies a drawing representing the shape of the level, and a pattern which drives the structure of the level. Sketch-2-Tilemap automatically generate levels following the constraints specified in the input pattern on an irregular grid generated from the input sketch. Sketch-2-Tilemap automates the process of manual tilemap creation and allows the user to rapidly prototype and modify new level designs.