Chapter 14: Example 14-4: Pyramid Using beginShape(TRIANGLES)

// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com

// Example 14-4: Pyramid using beginShape(TRIANGLES)

void setup() {
  size(200,200,P3D);
}

void draw() {
  background(255);
  
  // The pyramid's vertices are drawn relative to a centerpoint.
  // Therefore, we call translate() to place the pyramid properly in the window.
  // A slightly better option might be to include the translate in the drawPyramid() function and pass in x,y,z as arguments
  translate(100,100,0); 
  drawPyramid(150);
}

// The function sets the vertices for the pyramid around the centerpoint at a flexible distance, 
// depending on the number passed in as an argument.
void drawPyramid(int t) { 
  
  stroke(0);
  
  // this pyramid has 4 sides, each drawn as a separate triangle
  // each side has 3 vertices, making up a triangle shape
  // the parameter " t " determines the size of the pyramid
  beginShape(TRIANGLES);
  
  fill(255,150); // Note that each polygon can have its own color.
  vertex(-t,-t,-t);
  vertex( t,-t,-t);
  vertex( 0, 0, t);
  
  fill(150,150);
  vertex( t,-t,-t);
  vertex( t, t,-t);
  vertex( 0, 0, t);
  
  fill(255,150);
  vertex( t, t,-t);
  vertex(-t, t,-t);
  vertex( 0, 0, t);
  
  fill(150,150);
  vertex(-t, t,-t);
  vertex(-t,-t,-t);
  vertex( 0, 0, t);
  
  endShape();
}