        distY = (y - mapY) * deltaY

        for j in range(20):
            if distX < distY:
                mapX = mapX + stepX
                if arena[mapX][mapY]:
                    if thisRow != mapX or thisSide != 0:
                        if i > 0:
                            data.append(i)
                            data.append(lastHeight)
                        data.append(i)
                        data.append(distX)
                        thisSide = 0
                        thisRow = mapX