This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

Interactive Toroid by Ira Greenberg.

Illustrates the geometric relationship between Toroid, Sphere, and Helix 3D primitives, as well as lathing principal.

Instructions:
UP arrow key pts++
DOWN arrow key pts--
LEFT arrow key segments--
RIGHT arrow key segments++
'a' key toroid radius--
's' key toroid radius++
'z' key initial polygon radius--
'x' key initial polygon radius++
'w' key toggle wireframe/solid shading
'h' key toggle sphere/helix

```
int pts = 40;
float angle = 0;
float radius = 60.0;

// lathe segments
int segments = 60;
float latheAngle = 0;
float latheRadius = 100.0;

//vertices
PVector vertices[], vertices2[];

// for shaded or wireframe rendering
boolean isWireFrame = false;

// for optional helix
boolean isHelix = false;
float helixOffset = 5.0;

void setup(){
size(640, 360, P3D);
}

void draw(){
background(50, 64, 42);
// basic lighting setup
lights();
// 2 rendering styles
// wireframe or solid
if (isWireFrame){
stroke(255, 255, 150);
noFill();
}
else {
noStroke();
fill(150, 195, 125);
}
//center and spin toroid
translate(width/2, height/2, -100);

rotateX(frameCount*PI/150);
rotateY(frameCount*PI/170);
rotateZ(frameCount*PI/90);

// initialize point arrays
vertices = new PVector[pts+1];
vertices2 = new PVector[pts+1];

// fill arrays
for(int i=0; i<=pts; i++){
vertices[i] = new PVector();
vertices2[i] = new PVector();
if (isHelix){
segments)/2;
}
else{
}
angle+=360.0/pts;
}

// draw toroid
latheAngle = 0;
for(int i=0; i<=segments; i++){
for(int j=0; j<=pts; j++){
if (i>0){
vertex(vertices2[j].x, vertices2[j].y, vertices2[j].z);
}
vertices2[j].z = vertices[j].z;
// optional helix offset
if (isHelix){
vertices[j].z+=helixOffset;
}
vertex(vertices2[j].x, vertices2[j].y, vertices2[j].z);
}
// create extra rotation for helix
if (isHelix){
latheAngle+=720.0/segments;
}
else {
latheAngle+=360.0/segments;
}
endShape();
}
}

/*
left/right arrow keys control ellipse detail
up/down arrow keys control segment detail.
'a','s' keys control lathe radius
'z','x' keys control ellipse radius
'w' key toggles between wireframe and solid
'h' key toggles between toroid and helix
*/
void keyPressed(){
if(key == CODED) {
// pts
if (keyCode == UP) {
if (pts<40){
pts++;
}
}
else if (keyCode == DOWN) {
if (pts>3){
pts--;
}
}
// extrusion length
if (keyCode == LEFT) {
if (segments>3){
segments--;
}
}
else if (keyCode == RIGHT) {
if (segments<80){
segments++;
}
}
}
if (key =='a'){
}
}
else if (key == 's'){
}
if (key =='z'){
}
}
else if (key == 'x'){
}
// wireframe
if (key =='w'){
if (isWireFrame){
isWireFrame=false;
}
else {
isWireFrame=true;
}
}
// helix
if (key =='h'){
if (isHelix){
isHelix=false;
}
else {
isHelix=true;
}
}
}

```