R/utils.r

In r-gris/gris: A Flexible Geometry and Topology Model for Spatial Data in R

v3ToLong <- function(x) data_frame(.vx0 = as.vector(t(as.matrix(x[,1:3]))), .tr0 = rep(x$.tr0, each = 3))
tricentroids <- function(x) {
  x$tXv %>% dplyr::select_('.vx1', '.vx2', '.vx3', '.tr0') %>% v3ToLong %>% inner_join(x$v) %>% 
    group_by_('.tr0') %>% summarize(x = mean(x), y = mean(y)) %>% dplyr::select_('x', 'y', '.tr0')
}

tribbox <- function(x) {
  x$tXv %>% dplyr::select('.vx1', '.vx2', '.vx3', '.tr0') %>% v3ToLong %>% inner_join(x$v) %>% 
    group_by('.tr0') %>% summarize(xmin = min(x), xmax = max(x), ymin = min(y), ymax = max(y))
}

vcrossp <- function( a, b ) {
  result <- matrix( NA, nrow( a ), 3 )
  result[,1] <- a[,2] * b[,3] - a[,3] * b[,2]
  result[,2] <- a[,3] * b[,1] - a[,1] * b[,3]
  result[,3] <- a[,1] * b[,2] - a[,2] * b[,1]
  result
}


# 
# 
# SameSide <- function(p1,p2, a,b) {
#   cp2 = vcrossp(b-a, p2-a)
#   a <- mkm(a, nrow(p1))
#   b <- mkm(b, nrow(p1))
#   p2 <- mkm(p2, nrow(p1))
#   cp1 = vcrossp(b-a, p1- a)
#   c(cp1 %*% t(cp2)) >=0 
# }
# 
# PointInTriangle <- function(p, triangle) {
#   a <- triangle[1L,,drop=FALSE]
#   b <- triangle[2L,,drop=FALSE]
#   c <- triangle[3L,,drop=FALSE]
#   SameSide(p,a, b,c) & SameSide(p,b, a,c) & SameSide(p,c, a,b)
# }
# 
# #PointInTriangle(pts[,,drop=FALSE], triangle)
# 
# 
# pit <- function(x, xy) {
#   tbbox <- tribbox(x)
#   df <- NULL
#   ##ibox <- vector("list", nrow(tbbox))
#   for (i in seq(nrow(tbbox))) {
#     testme <- which(xy[,1] >= tbbox$xmin[i] & xy[,1] <= tbbox$xmax[i] &
#                       xy[,2] >= tbbox$ymin[i] & xy[,2] <= tbbox$ymax[i])
#     if (length(testme) > 0) {
#       triangle <- x$tXv[i, ] %>% v3ToLong %>% inner_join(x$v, ".vx0") %>% distinct(.vx0) %>% 
#         dplyr::transmute(x, y, z = 0) %>% as.matrix
#       test <-  PointInTriangle(xy[testme,,drop = FALSE ], triangle)
#       #  print(i)
#       if (any(test)) df <- bind_rows(df, data_frame(.xy0 = testme[test], .tr0 = rep(x$oXt$.tr0[i], sum(test))))
#     }
#   }
#   df
# }