stla

## TennisBallCheckerBoardFourCorners.R
library(cgalMeshes)
library(rgl)

# https://laustep.github.io/stlahblog/posts/TennisBall.html ####
f <- function(x, y, z) { # Enneper surface: f=0
  64*z^9 - 128*z^7 + 64*z^5 - 702*x^2*y^2*z^3 - 18*x^2*y^2*z +
    144*(y^2*z^6-x^2*z^6) + 162*(y^4*z^2-x^4*z^2) + 27*(y^6-x^6) +
    9*(x^4*z+y^4*z) + 48*(x^2*z^3+y^2*z^3) - 432*(x^2*z^5+y^2*z^5) +
    81*(x^4*y^2-x^2*y^4) + 240*(y^2*z^4-x^2*z^4) - 135*(x^4*z^3+y^4*z^3)
}

## SpaceBackground.png

      
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                stla
                / SpaceBackground.png
            
            
              Last active
              September 7, 2023 09:31
            
              
                Torus with metamorphosing Weierstrass texture
              
          
## runcinatedTesseract.R
library(rgl)
library(Rvcg)

# vertices ####
nvertices <- 64L
vertices <-
  rbind(
    c(-1, -1, -1, -1 - sqrt(2)),
    c(1, -1, -1, -1 - sqrt(2)),
    c(-1, 1, -1, -1 - sqrt(2)),

## rotoide.pov
#version 3.8;
global_settings { assumed_gamma 1 }
#include "colors.inc"
#include "textures.inc"

/* camera */
camera {
    location <-11, 7,-32>
    look_at 0
    angle 45

## closedTube.jl
using LinearAlgebra
using Quaternions
using Meshes
using MeshViz
using GLMakie

function quaternionFromTo(u, v)
  re = 1 + sqrt((1.0 + dot(u, v)) / 2.0)
  w = cross(u, v) / 2.0 / re
  return Quaternion(re, w[1], w[2], w[3])

## gyroGreatDodecicosahedron.R
library(rgl)

triangulateFace <- function(face) { # only for convex face !
  M <- matrix(NA_integer_, nrow = 3L, ncol = length(face)-2L)
  for(i in 2L:(length(face)-1L)) {
    M[, i-1L] <- c(face[1L], face[i], face[i+1L])
  }
  M
}

## greatDodecicosahedron.R
triangulateFace <- function(face) { # only for convex face !
  M <- matrix(NA_integer_, nrow = 3L, ncol = length(face)-2L)
  for(i in 2L:(length(face)-1L)) {
    M[, i-1L] <- c(face[1L], face[i], face[i+1L])
  }
  M
}

# http://dmccooey.com/polyhedra/GreatDodecicosahedron.html
C0 = (3 - sqrt(5)) / 4

## .gitignore
*.Rproj
.Rproj.user/
.Rhistory

## .gitignore
*.Rproj

## invertedCube.R
library(rgl)

iota <- function(x) x / c(crossprod(x))

q <- cgalMeshes:::quaternionFromTo(c(1, 1, 1)/sqrt(3), c(1, 0, 0))
R <- onion::as.orthogonal(q)


cube <- as.tmesh3d(
  translate3d(
	library(cgalMeshes)
	library(rgl)

	# https://laustep.github.io/stlahblog/posts/TennisBall.html ####
	f <- function(x, y, z) { # Enneper surface: f=0
	64z^9 - 128z^7 + 64z^5 - 702x^2y^2z^3 - 18x^2y^2*z +
	144(y^2z^6-x^2z^6) + 162(y^4z^2-x^4z^2) + 27*(y^6-x^6) +
	9(x^4z+y^4z) + 48(x^2z^3+y^2z^3) - 432(x^2z^5+y^2*z^5) +
	81(x^4y^2-x^2y^4) + 240(y^2z^4-x^2z^4) - 135(x^4z^3+y^4*z^3)
	}
	library(rgl)
	library(Rvcg)

	# vertices ####
	nvertices <- 64L
	vertices <-
	rbind(
	c(-1, -1, -1, -1 - sqrt(2)),
	c(1, -1, -1, -1 - sqrt(2)),
	c(-1, 1, -1, -1 - sqrt(2)),
	#version 3.8;
	global_settings { assumed_gamma 1 }
	#include "colors.inc"
	#include "textures.inc"

	/* camera */
	camera {
	location <-11, 7,-32>
	look_at 0
	angle 45
	using LinearAlgebra
	using Quaternions
	using Meshes
	using MeshViz
	using GLMakie

	function quaternionFromTo(u, v)
	re = 1 + sqrt((1.0 + dot(u, v)) / 2.0)
	w = cross(u, v) / 2.0 / re
	return Quaternion(re, w[1], w[2], w[3])
	library(rgl)

	triangulateFace <- function(face) { # only for convex face !
	M <- matrix(NA_integer_, nrow = 3L, ncol = length(face)-2L)
	for(i in 2L:(length(face)-1L)) {
	M[, i-1L] <- c(face[1L], face[i], face[i+1L])
	}
	M
	}
	library(rgl)

	iota <- function(x) x / c(crossprod(x))

	q <- cgalMeshes:::quaternionFromTo(c(1, 1, 1)/sqrt(3), c(1, 0, 0))
	R <- onion::as.orthogonal(q)


	cube <- as.tmesh3d(
	translate3d(