//Move ball with a direction
         ballx += spd*cosv(ball_dir)*time_step;
         bally += spd*sinv(ball_dir)*time_step;
         
         //Collision with "walls"
         -------------------------------------
         if ((ballx > game_minx & ballx+6 < game_maxx)){ //game_minx = 1/3 of screen_size.x and game_maxx = 2/3 screen_size.x  
            
            ball_dir = ball_dir; //Keep the direction
         }else{//If out of boundaries
            ball_dir = (180 - abs(ball_dir)); //Change the direction
         }

         //Checking collision with platforms!
         if (rect_collision(P_ball.pos_x, P_ball.pos_y, P_ball.size_x, P_ball.size_y, P_ai.pos_x, P_ai.pos_y, P_ai.size_x, P_ai.size_y)
            | rect_collision(P_ball.pos_x, P_ball.pos_y, P_ball.size_x, P_ball.size_y, P_player.pos_x, P_player.pos_y, P_player.size_x, P_player.size_y)){
            ball_dir = (180 - abs(ball_dir)); //Trying to change dir here.
         }

///////////////////////////////
#include <acknex.h>
#include <default.c>

var ball_dir;
var ballx;
var bally;

var vBall[3];
var spd = 20;

var game_start = 0;
var game_minx = 267;
var game_maxx = 533;



PANEL* P_player =
{
   //pos_x = 0; 
   pos_y = 550;
   size_x = 100;
   size_y = 10;
   flags = SHOW | LIGHT;
}

PANEL* P_ai =
{
   pos_x = 0;
   pos_y = 50;
   size_x = 100;
   size_y = 10;
   flags = SHOW | LIGHT;
} 

PANEL* P_ball =
{
   pos_x = 0;
   pos_y = 0;
   size_x = 6;
   size_y = 6; 
   flags = SHOW | LIGHT;
}

function rect_collision(var x1, var y1, var w1, var h1, var x2, var y2, var w2, var h2)
{ 
   
	if (x1 > (x2 + w2) | (x1 + w1) < x2){return (0);}
	if (y1 > (y2 + h2) | (y1 + h1) < y2){return (0);}
	return (1);
}

function hcenter_panel(PANEL* panel)
{
   panel.pos_x = (screen_size.x - panel.size_x)/2;
   //panel.pos_y = (screen_size.y - panel.size_y)/2;
}

function launch_ball()
{
   ball_dir = -60; //-random2(30, 150);
   vBall = vector(spd*cosv(ball_dir)*time_step, spd*sinv(ball_dir)*time_step, 0);
}

function trace_mouse(PANEL* panel)
{
   panel.pos_x = mouse_pos.x-50;
   panel.pos_x = clamp(panel.pos_x,game_minx, game_maxx-100);
}

//==============================================================================================
function main()
{
   video_mode = 7; 
   mouse_mode = 4; 
   random_seed(0);
   wait(3);
   
   hcenter_panel(P_player);
   hcenter_panel(P_ai);
   vec_set(P_ball.blue,vector(0,0,200));
   
   while(1)
   {
      
      trace_mouse(P_player); //move platform with the mouse
      
      
      if (game_start == 0){
         
         //ball is moving with the platform. Works!
         vBall[1] = P_player.pos_x + (P_player.size_x/2) - 3;
         vBall[2] = P_player.pos_y - P_ball.size_y - 1;
         
         //Hitting a left button launches the ball
         if (mouse_left == 1){
         launch_ball();
         game_start = 1;
         }
         
      }else{
         //Keep the ball moving. Wroks!
         vBall[1] += spd*cosv(ball_dir)*time_step;
         vBall[2] += spd*sinv(ball_dir)*time_step;
         
         
         //Collision with walls! ------------------------------------
         if (vBall[1] < game_minx){ //Left side of the game area
         vec_cross(vBall, 2*abs(vec_dot(vBall, vector(1,0,0))), vector(1,0,0));
         //vec_bounce(vBall, vector(1,0,0));
         }
         
         if (vBall[1]+6 > game_maxx){ //Right side of the game area
         vec_cross(vBall, 2*abs(vec_dot(vBall, vector(-1,0,0))), vector(-1,0,0));
         //vec_bounce(vBall, vector(-1,0,0));
         }

         
         if (rect_collision(P_ball.pos_x, P_ball.pos_y, P_ball.size_x, P_ball.size_y, P_ai.pos_x, P_ai.pos_y, P_ai.size_x, P_ai.size_y)
            | rect_collision(P_ball.pos_x, P_ball.pos_y, P_ball.size_x, P_ball.size_y, P_player.pos_x, P_player.pos_y, P_player.size_x, P_player.size_y)){
            //ball_dir = (180 - abs(ball_dir));
         }
         //-----------------------------------------------------------
      }
      //Keep the panel moving along those coordinates
      P_ball.pos_x = vBall[1]; //ballx;
      P_ball.pos_y = vBall[2]; //bally;
      
      //moving AI Platform.
      P_ai.pos_x = P_ball.pos_x - ((P_ai.size_x-P_ball.size_x)/2);
      P_ai.pos_x = clamp(P_ai.pos_x,game_minx, game_maxx-100);
      
            
      draw_line(vector(game_minx,0,0),NULL,100); // move to first corner   
      draw_line(vector(game_maxx,0,0),vector(0,0,255),100);   
      draw_line(vector(game_maxx,599,0),vector(0,0,255),100);   
      draw_line(vector(game_minx,599,0),vector(0,0,255),100);   
      draw_line(vector(game_minx,0,0),vector(0,0,255),100);
      
   wait(1);
   }
   
}
//==============================================================================================

[code]var c[3] = {480, 543, 0};
var n[3] = {-1, 0, 0};
var b[3];

//n = vec_normalize(n,1);
// b = 2*|<c,n>|*n + c  Bounce vector's formula.
var a;

function main()
{
   video_mode = 7;
   wait(3);
   
   a = 2*abs(vec_dot(c, n));
   vec_set(b, vector(a*n[0], a*n[1],0));
   vec_add(b, c);
}

//Collision with walls! ------------------------------------
         if (vBall[0] < game_minx){ //Left side of the game area
         
         // b = 2*|<c,n>|*n + c  Bounce vector's formula.
         //Into Parts:
         //a = 2*|c,n|
         //we change (0,0,0) to (a*(-1), a*0, 0) with vec_set
         //add (480, 543,0) and (-a, 0, 0)
         a = 2*abs(vec_dot(vBall, nvec_minx));
            vec_set(vBounce, vector(a*nvec_minx[0], a*nvec_minx[1],0));
            vec_add(vBall, vBounce);

         }