Hello all!

I have a slight problem. I have made a pong game that involves a human player and a computer player. The computer player is programmed by the paddle tracking the balls exact y position. But beacuse of this, the ball cannot get past the computers paddle at all! 

Does anyone know of a way to make the computer's paddle a bit slower than the ball but still track the position of the ball so that a human has a chance of scoring?

here is the code for the game:

1. //Variables for ball
2. float ball_x; //balls horizontal position
3. float ball_y; //balls vertical position
4. float ball_hori_speed = 2; //ball speed in x axis
5. float ball_size = 15;  // ball size according to it's radius
6. float ball_vert_speed = 1;  // ball speed in y axis
8. //Paddle Variables
9. int pad_width = 10; //paddle's Width
10. int pad_height = 30; //paddle's height
12. //score variable
13. int comp_score; //Computer's score
14. int hu_score; //Human's score
16. //General variables
17. color c = color(105,255,98); //Colour corresponding the colour selector
18. PFont font; //fonts variable
20. void setup(){
21. size(400,400); //Window size
22. noStroke(); //no outline for game ball
23. smooth(); //where this is declared shapes have smooth edges 
24.  font = loadFont("LucidaConsole-26.vlw"); //where "font" is declared. use this font type and size
25. textFont(font); //Use the "font" varaible
26. ball_y = height/2; //ball's vertical position
27. ball_x = width/2; //ball's horizonal position 
28. } 
30. void draw(){
31. background(0);
32. rectMode(RADIUS);
33. ellipseMode(RADIUS);
35. //text
36. fill(c);
37. textSize(20);
38. text("Human",3,22);
39. text("Computer",300,22);
40. text(hu_score, 150, 22);
41. text(comp_score,250,22);
42. stroke(c);
43. line(0,27,400,27);
45.  //center line
46. for(int i = 27; i < 400; i += 30){
47. line(200,i,200,i + 10);
48. }
50. ball_x += ball_hori_speed; //adds speed to ball hori position 
51. ball_y += ball_vert_speed;  //adds speed to ball vert pos
52. if(ball_x > width+ball_size) { //if hori pos is greater than screen width+ball size
53. ball_x = -width/2 - ball_size; //ball hori pos is minus half width minus ball size
54. ball_y = random(27, height);
55. }
    
57. // Constrain paddle to screen
58. float cpad_y = constrain(ball_y, 59 , height); //tracks ball y position
59. float pad_y = constrain(mouseY, 59 , height);
61. // Test to see if the ball is touching the paddle
62. float py = width-15 - pad_width - ball_size;
63. if(ball_x == py 
64. && ball_y > cpad_y - pad_height - ball_size 
65. && ball_y < cpad_y + pad_height + ball_size) {
66. ball_hori_speed *= -1;
67. if(mouseY != pmouseY) {
68. ball_vert_speed = (mouseY-pmouseY)/2.0;
69. if(ball_vert_speed >  5) { ball_vert_speed =  5; }
70. if(ball_vert_speed < -5) { ball_vert_speed = -5; }
71. }
72.  }
74. float py1 = 15 + pad_width + ball_size;
75. if(ball_x == py1 
76. && ball_y > pad_y - pad_height - ball_size 
77. && ball_y < pad_y + pad_height + ball_size) {
78. ball_hori_speed *= -1;
79. if(mouseY != pmouseY) {
80. ball_vert_speed = (mouseY-pmouseY)/2.0;
81. if(ball_vert_speed >  5) { ball_vert_speed =  5; }
82. if(ball_vert_speed < -5) { ball_vert_speed = -5; }
83. }
84. }
86. //Scoring system and ball position reset
87. if(ball_x < -width/4){
88. comp_score = comp_score +1; ball_x = 200;
89. }
91. if(comp_score >= 5){
92. ball_vert_speed = 0; ball_hori_speed = 0;
93. text("Game Over\nComputer Wins!",210,175); 
94. }
96. if((comp_score == 5) && (mousePressed)){
97. exit();
98. } 
100. //Human score
101. if(ball_x > width){
102. hu_score = hu_score +1; ball_x = 200;
103. }
105. if(hu_score >= 15){
106. ball_vert_speed = 0; ball_hori_speed = 0;
107. text("Game Over\nyou win",60,175);
108. }
110. // If the ball is touching top or bottom edge, reverse direction
111. if(ball_y > height-ball_size) {
112. ball_vert_speed = ball_vert_speed * -1;
113. }
115. if(ball_y < ball_size+27) {
116. ball_vert_speed = ball_vert_speed * -1;
117. }
119. // Draw ball
120. fill(c);
121. noStroke();
122. ellipse(ball_x, ball_y, ball_size, ball_size);
124. // Draw the paddles
125. fill(c);
126. rect(width-15, cpad_y, pad_width, pad_height);
127. rect(15,pad_y,pad_width,pad_height);
128. }