sphericalTriangle: Spherical triangle

In cgalMeshes: R6 Based Utilities for 3D Meshes using 'CGAL'

Spherical triangle

Description

Mesh of a spherical triangle.

Usage

sphericalTriangle(A, B, C, center = c(0, 0, 0), radius = 1, iterations = 4)

Arguments

A, B, C	the three vertices of the triangle, each given either as a pair of numbers: the polar angle (between 0 and pi) and the azimuthal angle (between 0 and 2pi), or as Cartesian coordinates
center	center of the sphere
radius	radius of the sphere, ignored if the three vertices are given as Cartesian coordinates
iterations	number of iterations used to construct the mesh of the sphere

Value

A cgalMesh object. The mesh has normals.

Examples

library(cgalMeshes)
library(rgl)
# orthant
A <- c(0, pi/2)
B <- c(pi/2, pi/2)
C <- c(0, 0)
mesh <- sphericalTriangle(A, B, C)
rmesh <- mesh$getMesh()
open3d(windowRect = 50 + c(0, 0, 512, 512))
view3d(30, 30)
shade3d(rmesh, color = "red")
wire3d(rmesh)

# spherical icosahedron ####
library(cgalMeshes)
library(rgl)
icosahedron <- icosahedron3d()
vertices    <- icosahedron[["vb"]][-4L, ]
faces       <- icosahedron[["it"]]
colors <- rainbow(ncol(faces))
open3d(windowRect = 50 + c(0, 0, 512, 512))
for(i in 1L:ncol(faces)) {
  triangle <- faces[, i]
  A <- vertices[, triangle[1L]]
  B <- vertices[, triangle[2L]]
  C <- vertices[, triangle[3L]]
  mesh <- sphericalTriangle(A, B, C)
  rmesh <- mesh$getMesh()
  shade3d(rmesh, color = colors[i])
  wire3d(rmesh)
}

cgalMeshes documentation built on July 9, 2023, 7:45 p.m.