to return to the last page click here

#include <stdlib.h>
#include <stdio.h>
#include "font.h"

//some useful colors
#define BLACK 0x0000
#define WHITE 0xFFFF
#define BLUE 0xEE00
#define CYAN 0xFF00
#define GREEN 0x0EE0
#define RED 0x00FF
#define MAGENTA 0xF00F
#define BROWN 0x0D0D

//defines for the video system
unsigned short* videoBuffer = (unsigned short*)0x6000000;
#define DISPLAY_CONTROLLER *(unsigned long*)0x4000000
#define VIDC_BASE_HALF ((volatile unsigned short int*) 0x04000000)
#define VCOUNT (VIDC_BASE_HALF[3])

#define VIDEO_MODE_3 0x3
#define BACKGROUND2 0x400
#define SCREEN_W 240
#define SCREEN_H 160

//game constants
#define BALL_SIZE 6
#define PADDLE_WIDTH 8
#define PADDLE_HEIGHT 28
#define PADDLE_SPEED 2

//global variables
int paddleX[3];
int paddleY[3];
int ballX, ballY;
int velX = 2, velY = 1;
int score1=0,score2=0;

void setMode(int mode)
{
DISPLAY_CONTROLLER = mode | BACKGROUND2;
}

inline void drawpixel(int x, int y, unsigned short color)
{
videoBuffer[y * 240 + x] = color;
}

inline unsigned short getpixel(int x, int y)
{
return videoBuffer[y * 240 + x];
}

void drawbox(int left, int top, int right, int bottom, unsigned short color)
{
int x, y;
for(y = top; y < bottom; y++)
for(x = left; x < right; x++)
drawpixel(x, y, color);
}

int buttonPressed(int button)
{
//pointer to the button interface
volatile unsigned int *BUTTONS = (volatile unsigned int *)0x04000130;

//see if UP button is pressed
if (!((*BUTTONS) & button))
return 1;
else
return 0;
}

//draw text using characters contained in font.h
void print(int left, int top, char *str, unsigned short color)
{
int x, y, draw;
int pos = 0;
char letter;

//look at all characters in this string
while (*str)
{
//get current character ASCII code
letter = (*str++) - 32;

//draw the character
for(y = 0; y < 8; y++)
for(x = 0; x < 8; x++)
{
//grab a pixel from the font character
draw = font[letter * 64 + y * 8 + x];

//if pixel = 1, then draw it
if (draw)
drawpixel(left + pos + x, top + y, color);
}

//jump over 8 pixels
pos += 8;
}
}

void printScores()
{
char s[5];

//erase scores
drawbox(0,0,20,10,BLACK);
drawbox(220,0,239,10,BLACK);

//display scores
sprintf(s,"%i",score1);
print(5,0,s,WHITE);

sprintf(s,"%i",score2);
print(220,0,s,WHITE);
}

void eraseBall()
{
drawbox(ballX, ballY, ballX+BALL_SIZE, ballY+BALL_SIZE, BLACK);
}

void updateBall()
{
ballX += velX;
ballY += velY;

//did ball hit right wall?
if (ballX > SCREEN_W - BALL_SIZE - 1)
{
velX *= -1;
score1++;
}

//did ball hit left wall?
if (ballX < 1)
{
velX *= -1;
score2++;
}

//did ball hit top or bottom walls?
if (ballY < 12 || ballY > SCREEN_H - BALL_SIZE - 1)
velY *= -1;

}

void drawBall()
{
drawbox(ballX, ballY, ballX+BALL_SIZE, ballY+BALL_SIZE, MAGENTA);
}

void erasePaddle1()
{
drawbox(paddleX[1], paddleY[1], paddleX[1] + PADDLE_WIDTH, paddleY[1] + PADDLE_HEIGHT, BLACK);
}

void updatePaddle1()
{
int py = paddleY[1] + PADDLE_HEIGHT/2;

//only move computer paddle if ball is moving toward left
if (velX < 0 && ballX < 120) {

if (py > ballY) {
paddleY[1] -= 1;
if (paddleY[1] < 12) paddleY[1] = 12;
}

if (py < ballY) {
paddleY[1] += 1;
if (paddleY[1] > 160-PADDLE_HEIGHT)
paddleY[1] = 160-PADDLE_HEIGHT;
}
}

}

void drawPaddle1()
{
drawbox(paddleX[1], paddleY[1], paddleX[1] + PADDLE_WIDTH, paddleY[1] + PADDLE_HEIGHT, CYAN);
}

void erasePaddle2()
{
drawbox(paddleX[2], paddleY[2], paddleX[2] + PADDLE_WIDTH, paddleY[2] + PADDLE_HEIGHT, BLACK);
}

void updatePaddle2()
{
//check for UP button press
if (buttonPressed(64))
{
if (paddleY[2] > 10)
paddleY[2] -= PADDLE_SPEED;
}

//check for DOWN button press
if (buttonPressed(128))
{
if (paddleY[2] < SCREEN_H - PADDLE_HEIGHT - 1)
paddleY[2] += PADDLE_SPEED;
}
}

void drawPaddle2()
{
drawbox(paddleX[2], paddleY[2], paddleX[2] + PADDLE_WIDTH, paddleY[2] + PADDLE_HEIGHT, CYAN);
}

void checkCollisions()
{
int x,y;

//see if ball hit a paddle
x = ballX + BALL_SIZE/2;
y = ballY + BALL_SIZE/2;
if (getpixel(x,y) != BLACK)
{
//we have a hit!
velX *= -1;
ballX += velX;
}
}

void waitRetrace()
{
while (VCOUNT != 160);
while (VCOUNT == 160);
}

int main(void)
{
//init video mode 3 (240x160)
setMode(VIDEO_MODE_3);

//init the ball
ballX = SCREEN_W / 2 - BALL_SIZE / 2;
ballY = 40;

//init the left paddle
paddleX[1] = 10;
paddleY[1] = SCREEN_H / 2 - PADDLE_HEIGHT / 2;

//init the right paddle
paddleX[2] = SCREEN_W - 20;
paddleY[2] = SCREEN_H / 2 - PADDLE_HEIGHT / 2;

//clear the screen
drawbox(0, 0, 239, 159, BLACK);

//display title
print(120-16,1,"PONG",BLUE);

//game loop
while(1)
{
waitRetrace();

eraseBall();
erasePaddle1();
erasePaddle2();

updatePaddle1();
updatePaddle2();
updateBall();

drawPaddle1();
drawPaddle2();

checkCollisions();
drawBall();

printScores();
}

return 0;
}