Hey guys. Just last Friday I started really working on P3D for a simple FPS RPG that I want to make. The first thing I'm starting with is a free-looking, free-moving camera controlled by the mouse and WASD keys(like you see in many games). I'm using the Robot Java class to keep the mouse in the center and record its movements, but I'm having issues with grasping the concepts of the camera class. I get what eye, center, and up do, but I cannot figure out how to manipulate center and eye well. I have studied the camera manipulations of Chrisr/polar's first person program extensively:
http://www.openprocessing.org/sketch/25255
and another first person dungeon generator by RyanD:
http://www.openprocessing.org/sketch/23227

Hello all.
Just a quick question.
How do you find the value of a variable in the previous frame. Is there any command?
For example :

int a, b;

void setup() {
  int a = 0;
}

void draw() {
  a += 5;
  b = (value of a in previous frame)
}

How would you find b?
If your just using mouse commands you can use pmouse() but how do you do this for created variables?

Hello all!
I'm fairly new to processing and need some help with collision.
I am trying to figure out how to make the ball correctly bounce off of the paddle and the walls.
I have looked at the pong example game and it helps but I can't grasp how collisions work in programming.
Any help with my code or explaining how collisions work would be appreciated.
Sorry about the lack of objects but I tried to keep the code as clean as possible.
Any responses are appreciated.
Here's the code.

int paddleWidth;
int paddleHeight;
int paddleX;
int paddleY;
float paddleSpeed;

int ballRadius;
float ballX;
float ballY;
float dirX;
float dirY;


void setup () {
 size(640, 480);
 rectMode(CENTER);
 ellipseMode(CENTER);
 paddleWidth = 120;
 paddleHeight = 10;
 paddleX = width/2;
 paddleY = height - paddleHeight;
 paddleSpeed = 10;
 ballRadius = 10;
 ballX = width/2;
 ballY = -height + height - ballRadius;
 dirY = 1;
 dirX = 0;
}

void draw() {
  BackScreen();
  Paddle();
  Ball();
  BallMovement();
  PaddleControl();
  PaddleContain();
  Miss();
}

void BackScreen() {
  rectMode(CORNER);
  noStroke();
  fill(0);
  rect(0, 0, width, height);
}

void Paddle() {
  rectMode(CENTER);
  fill(255);
  noStroke();
  rect(paddleX, paddleY, paddleWidth, paddleHeight);
}

void Ball() {
  fill(255);
  noStroke();
  smooth();
  ellipse(ballX, ballY, ballRadius*2, ballRadius*2);
}

void BallMovement() {
  ballY += dirY * 5.0;
  ballX += dirX;
}

void BallBounce() {
  if(ballY < height - paddleHeight && ballX < paddleX + (paddleWidth/2)
  && ballX > paddleX - (paddleWidth/2)) {
    dirY *= -1;
  }
}

void PaddleControl() {
  if(keyPressed && paddleX + (paddleWidth/2) < width) {
    if(key == CODED) {
      if(keyCode == RIGHT) {
        paddleX += paddleSpeed;
      }
    }
  }
  if(keyPressed && paddleX - (paddleWidth/2) > width - width) {
    if(key == CODED) {
      if(keyCode == LEFT) {
        paddleX -= paddleSpeed;
      }
    }
  }
}

void PaddleContain() {
}

void Miss() {
  if(ballY > height) {
    ballY = height - height - (ballRadius*2);
  }
}