I need help on the void keyPressed() part, any suggestions;
float x;
float y;
float xSpeed;
float ySpeed;
float theta;
float rotationSpeed;
float gravityFactor;
boolean drawSquare = true;

void initialize()
{
  color c;
  x = 0;
  y = 0;
  xSpeed = 1.0;
  ySpeed = 1.5;
  c = generateRandomColor();
  fill(c);
  rotationSpeed = radians(2);
  gravityFactor = 0.1;
  // fill(generateRandomColor());
}

void setup()
{
  size(300, 300);
  initialize();
}

void mousePressed()
{
  initialize();
}

void draw()
{
  background(255);
  if (drawSquare == true) {
    pushMatrix();

    translate(x, y);
    rotate(theta);
    rectMode(CENTER);
    rect(0, 0, 20, 20);
    popMatrix();
  }
  else
  {
    pushMatrix();

    translate(x, y);
    rotate (theta);
    triangle(-20, -10, -20, 10, 20, 0);
    popMatrix();// push, translate, rotate, draw triangle, pop
  }

  x = x + xSpeed;// Add the x speed to the x position

  y = y + ySpeed;// Add the y speed to the y position

  ySpeed = ySpeed + gravityFactor;// Add the gravity to the y speed

  theta = theta + rotationSpeed;//Add the speed of rotation to θ

  if (x < 0 || x > width)
  {
    xSpeed = -xSpeed;
  }

  if (y >= height)
  {
    ySpeed *= -0.9;
  }
}
// If the x position is off-screen, reverse the x speed.
//  If the y position is greater than the height of the
// sketch, set the y speed to -0.9 times its current value.


void keyPressed()
{
  //If the user presses the s or S key, your program will set the drawSquare variable to true to indicate that the program should draw squares.

  //If the user presses the t or T key, your program will set the drawSquare variable to false to indicate that the program should draw triangles.

  //If the user presses the c or C key, your program will call the generateRandomColor() function to change the fill color for the current shape.

  //This function will do nothing for any other keypresses.
}

color generateRandomColor()
{
  color result;
  result = color(random(0, 192), random(0, 192), random(0, 192));
  return result;
}