In the Drawing 3D primitives recipe, you've learned that Processing comes with two 3D primitives: the box and the sphere. Although these two shapes can be used to do great things, you might have more fun creating your own 3D shapes. We'll take a look at how you can create a flexible function to draw a cylinder in this recipe.
Just like in the previous recipes, you should start by importing the OpenGL library and setting up a window with a size of 640 x 480 pixels. The next thing we'll do is to write a function that will draw a cylinder to the screen. The code for the top and bottom of the cylinder should look familiar; we've used something similar in the Drawing custom shapes recipe, in the previous chapter. The code for the side of the cylinder is a little different.
void cylinder( int numSegments, float h, float r )
{
float angle = 360.0 / (float)numSegments;
// top
beginShape();
for ( int i = 0; i < numSegments; i++ ) {
float x = cos...