创建双折线屋顶(Gambrel)。常用于谷仓风格建筑。
roofGambrel(height, topLengthRatio, overhangX, overhangY)
attr x = roofGambrel(height, topLengthRatio, overhangX, overhangY)
@StartRule
Lot --> primitiveCube(6, 4, 6)
extrude(5)
comp(f) { top: Roof | side: Wall }
Roof --> roofGambrel(30)
color(0.5, 0.25, 0.15)
Wall --> color(0.75, 0.72, 0.68)