void setup() {
  size(800, 800, P3D);
}

void draw() {
  translate(400, 400);
  rotate(0.5, 0.5, 0, 0.0);
  cylinder(100, 200, 30);
}

void cylinder(float w, float h, int sides)
{
  float angle;
  float[] x = new float[sides+1];
  float[] z = new float[sides+1];
 
  //get the x and z position on a circle for all the sides
  for(int i=0; i < x.length; i++){
    angle = TWO_PI / (sides) * i;
    x[i] = sin(angle) * w;
    z[i] = cos(angle) * w;
  }
 
  //draw the top of the cylinder
  beginShape(TRIANGLE_FAN);
 
  vertex(0,   -h/2,    0);
 
  for(int i=0; i < x.length; i++){
    vertex(x[i], -h/2, z[i]);
  }
 
  endShape();
 
  //draw the center of the cylinder
  beginShape(QUAD_STRIP); 
 
  for(int i=0; i < x.length; i++){
    vertex(x[i], -h/2, z[i]);
    vertex(x[i], h/2, z[i]);
  }
 
  endShape();
 
  //draw the bottom of the cylinder
  beginShape(TRIANGLE_FAN); 
 
  vertex(0,   h/2,    0);
 
  for(int i=0; i < x.length; i++){
    vertex(x[i], h/2, z[i]);
  }
 
  endShape();
}