screeps room distance transform

main.js

function distanceTransform(roomName) {
    let vis = new RoomVisual(roomName);

    let topDownPass = new PathFinder.CostMatrix();
    for (let y = 0; y < 50; ++y) {
        for (let x = 0; x < 50; ++x) {
            if (Game.map.getTerrainAt(x, y, roomName) == 'wall') {
                topDownPass.set(x, y, 0);
            }
            else {
                topDownPass.set(x, y,
                    Math.min(topDownPass.get(x-1, y-1), topDownPass.get(x, y-1),
                        topDownPass.get(x+1, y-1), topDownPass.get(x-1, y)) + 1);
            }
        }
    }

    for (let y = 49; y >= 0; --y) {
        for (let x = 49; x >= 0; --x) {
            let value = Math.min(topDownPass.get(x, y),
                    topDownPass.get(x+1, y+1) + 1, topDownPass.get(x, y+1) + 1,
                    topDownPass.get(x-1, y+1) + 1, topDownPass.get(x+1, y) + 1);
            topDownPass.set(x, y, value);
            vis.circle(x, y, {radius:value/25});
        }
    }
    
    return topDownPass;
}

module.exports.loop = function() {
    let start = Game.cpu.getUsed();
    distanceTransform('sim');
    let end = Game.cpu.getUsed()
    console.log("cpu:", end - start);
}

This is really clever. I was scratching my head on how to do this. Super cool! Thanks

@shixish here's an updated conditional that resolves the deprecation.

Game.map.getRoomTerrain(roomName).get(x, y) == TERRAIN_MASK_WALL