//------------------------------------------------------------------------------
// Tutorial
// Subject: Pong
// Author: Roelf Leenders(el.moog@gmail.com)
// Started: 4-2-2005 (12:18:43h)
//------------------------------------------------------------------------------
program tutorial;

global
score[1];

//Graphics:
gr_ball;
gr_bat;


//GP Keys
__A = _control;
__B = _alt;
__SELECT = _space;
__START = _enter;
__R = _tab;
__L = _backspace;

begin
//initialize screen:
set_title("Serie Tutorial by Roelf Leenders");
full_screen = false;
set_mode(m320x240);

//Create graphics
gr_ball = new_map(10,10,8);
map_clear(0,gr_ball,13);

gr_bat = new_map(15,40,8);
map_clear(0,gr_bat,13);


//Create a ball process
ball();

//Create two bat processes
bat(20,_up,_down);
bat(300,__L,__R);


//Write the current score on screen
write(0,160,20,4,"-");
write_int(0,100,20,4,&score[0]);
write_int(0,220,20,4,&score[1]);

loop
  //If key start is pressed quit the game
  if(key(__START))
    exit("",0);
  end

  frame;
end

end

/*
Process of a typical ball in a Pong game. Despite being square it bounces off bats
and the screen edge, and detects when a point has been made and when it it bounced back
off a bat.
*/
Process ball();

private
//Speed of the ball
speedo;

//Holds the bat's process identification number in case it collides with one
bat_id;

begin

//Initialize start values for most variables
//*position
x = 160;
y = 120;
//*angle
angle = rand(0,360) * 1000;
//*ball speed
speedo = 500;
//*graphic of the process
graph = gr_ball;

loop
  //Makes it bounce off the top and bottom of the screen(0 and 240, but giving
  //the ball a 5 pixel radius)
  if(y<5 or y>235)
    //Incoming angle is outgoing angle!
    angle = -angle;
  end

  //if off the screen on the left(point for player with score[0]
  if(x<0)
    //Add one to the score
    score[0]++;
    //Reset speed to standard
    speedo = 500;
    //reset Position
    y = 120;
    x = 220;
  end

  //Same for the right screen edge, only with the other bat scoring
  if(x>320)
    score[1]++;
    speedo = 500;
    y = 120;
    x = 100;
  end

  //If it hits a bat
  if(bat_id = collision(type bat))
    angle = -angle + 180000;
    advance(3);
  end

  //Slowly increase the speed
  speedo+=3;
  //Move the ball in it's current direction
  advance(speedo/100);

  frame;
end

end

/*
A typical bat in a Pong game. It can move up and down with the keys
specified in the keyup and keydown parameters. x specifies the horizontal position on
screen.

*/
Process bat(x,keyup,keydown)

begin

//Start in the middle of the screen
y = 120;

//use the graphic made for the bat
graph = gr_bat;

loop
  //Move the bat vertically if buttons are pressed
  if(key(keyup))
    y -= 12;
  end
  
  if(key(keydown))
    y += 12;
  end

  //Limit the bat movement on the edges of the screen
  if(y < 20)
    y=20;
  end
  
  if(y > 220)
    y=220;
  end
  
  frame;
end

end