R/crownhull.R

In YplantQMC: Plant architectural analysis with Yplant and QuasiMC.

crownhull <- function(xyz, plotit=TRUE, alpha=0.8){

	if(inherits(xyz, "plant3d"))
		xyz <- do.call("rbind", lapply(xyz$leaves, function(x)x$XYZ))

	# construct the hull (gives area and volume)
	if(is.list(xyz) && !is.data.frame(xyz))
		p <- as.matrix(do.call("rbind", xyz))
	else
		p <- as.matrix(xyz)
	
	ch <- convhulln(p, "FA")

	# construct the hull for plotting
	if(plotit){
		ch2 <- t(convhulln(p, "Qt"))
		triangles3d(p[ch2,1],p[ch2,2],p[ch2,3],col="forestgreen",alpha=alpha)
	}

return(list(crownvolume=ch$vol, crownsurface=ch$area))
}