main.cpp

#include <GL/glut.h>
#include<stdio.h>
#include<stdlib.h>
#include <iostream>
#include<string>
#include <ctime>
#define ROWS 40.0
#define COLUMNS 40.0
#define MAX 60
#define UP 1
#define RIGHT 2
#define DOWN -1
#define LEFT -2
#define fps 10

using namespace std;
bool game_over = false;
int score = 0;
void random(int&, int&);
void output(int, int, char*);
void drawstring(int, int, char*, void*);
bool food = true;
int gridy = 40, gridx = 40;
int sDirection = RIGHT;
int foodx, foody;
int posx[MAX + 1] = { 20,20,20,20,20 };
int posy[MAX + 1] = { 20,19,18,17,16 };
int length = 5, df = 10;
void keyboard(unsigned char key, int x, int y)
{

    if (df == 10 && key == 13)
        df = 0;
    else if ((df == 0) && key == 27)
        df = 10;
    else if ((df == 0) && key == '1')
        df = 1;
    else if (df == 0 && key == '2')
        df = 2;
    else if (df == 0 && key == '3')
        df = 3;
    else if (key == 27)
        df = 0;
    glutPostRedisplay();
}

void frontscreen(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glLoadIdentity();

    // Background
    glClearColor(0.2, 0.2, 0.2, 1.0); // Dark gray backgroundz

    // Text color
    glColor3f(0.9, 0.9, 0.9); // Light gray text color

    drawstring(15, 15, "Press ENTER to go to the next screen", GLUT_BITMAP_HELVETICA_18);
    drawstring(3, 3, "Maximize window for better view", GLUT_BITMAP_HELVETICA_12);

    // Project title
    glColor3f(1.0, 0.8, 0.0); // Yellowish
    output(16, 20, "Computer Graphics Project");

    // Snake game title
    glColor3f(0.0, 1.0, 0.5); // Bluish green
    output(15, 38, "\"SNAKE GAME USING OPENGL\"");

    // "By" label
    glColor3f(1.0, 0.8, 1.0); // Light purple
    output(28, 15, "By:");

    // Names in different colors
    glColor3f(1.0, 0.0, 0.0); // Red
    output(30, 15, "Mohammed mostafa");
    glColor3f(0.0, 1.0, 0.0); // Green
    output(30, 13, "Albasel abobakr");
    glColor3f(0.0, 0.0, 1.0); // Blue
    output(30, 11, "Bassel rafaat");
    glColor3f(1.0, 1.0, 0.0); // Yellow
    output(30, 9, "Hasnaa abdelrahman");
    glColor3f(0.0, 1.0, 1.0); // Cyan
    output(30, 7, "Aya kamal");
    glColor3f(1.0, 0.5, 1.0); // Light purple
    output(30, 5, "Shimaa emad");

    output(40, 80, "");
    glFlush();
}

void startscreen()
{

    glClear(GL_COLOR_BUFFER_BIT);
    glClearColor(0.2, 0.2, 0.2, 1.0); // Dark gray background
    output(16, 30, "WELCOME TO THE GAME OF SNAKE ");
    output(18, 26, "1.NEW GAME");
    output(18, 24, "2.INSTRUCTIONS");
    output(18, 22, "3.QUIT");
    glFlush();
}

void instructions()
{
    glClear(GL_COLOR_BUFFER_BIT);
    glClearColor(0.2, 0.2, 0.2, 1.0); // Dark gray background
    output(18, 38, "INSTRUCTIONS:");
    glBegin(GL_LINES);
    glVertex2f(17, 37);
    glVertex2f(24, 37);
    glEnd();
    glColor3f(0, 1, 0);
    output(8, 30, "* Use your cursor keys: up, left, right, and down.");
    output(8, 28, "* Don't run the snake into the wall, or its own tail: you'll die.");
    output(8, 26, "* Eat the yellow food to gain points");
    output(8, 24, "* PRESS ESC TO GO TO MAIN MENU");
    glFlush();
}

void output(int x, int y, char* string)
{
    int len, i;

    glRasterPos2f(x, y);
    len = (int)strlen(string);
    for (i = 0; i < len; i++)
    {
        glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, string[i]);
    }
}

void drawstring(int x, int y, char* string, void* font)
{
    int len, i;

    glRasterPos2f(x, y);
    len = (int)strlen(string);
    for (i = 0; i < len; i++)
    {
        glutBitmapCharacter(font, string[i]);
    }
}

void draw_grid()
{
    glColor3d(1, 1, 0);  // Set color outside glBegin and glEnd

    // Left line
    glBegin(GL_QUADS);
    glVertex2d(0, 0);
    glVertex2d(1, 0);
    glVertex2d(1, 40);
    glVertex2d(0, 40);
    glEnd();

    // Right line
    glBegin(GL_QUADS);
    glVertex2d(39, 0);
    glVertex2d(40, 0);
    glVertex2d(40, 40);
    glVertex2d(39, 40);
    glEnd();

    // Top line
    glBegin(GL_QUADS);
    glVertex2d(0, 39);
    glVertex2d(40, 39);
    glVertex2d(40, 40);
    glVertex2d(0, 40);
    glEnd();

    // Bottom line
    glBegin(GL_QUADS);
    glVertex2d(0, 0);
    glVertex2d(40, 0);
    glVertex2d(40, 1);
    glVertex2d(0, 1);
    glEnd();
}

void draw_snake()
{
    for (int i = length - 1;i > 0;i--)
    {
        posx[i] = posx[i - 1];
        posy[i] = posy[i - 1];
    }

    switch (sDirection)
    {
    case UP:
        posy[0]++;
        break;
    case DOWN:
        posy[0]--;
        break;
    case RIGHT:
        posx[0]++;
        break;
    case LEFT:
        posx[0]--;
        break;
    }
    for (int i = 0;i < length;i++)
    {
        if (i == 0)
        {
            glColor3f(0.0, 1.0, 0.0);//green
        }
        else
        {
            glColor3f(0.0, 1.0, 1.0);
        }
        glBegin(GL_QUADS);
        glVertex2d(posx[i], posy[i]);
        glVertex2d(posx[i] + 1, posy[i]);
        glVertex2d(posx[i] + 1, posy[i] + 1);
        glVertex2d(posx[i], posy[i] + 1);
        glEnd();

    }
    if (posx[0] == 0 || posx[0] == gridx - 1 || posy[0] == 0 || posy[0] == gridy - 1) //snake touches red boundary
        game_over = true;
    else if (posx[0] == foodx && posy[0] == foody)
    {
        length++;
        food = true;
        score++;
        if (length > MAX)
            length = MAX;

    }
    for (int j = 1;j < length;j++)
    {
        if (posx[j] == posx[0] && posy[j] == posy[0])
            game_over = true;
    }

}
void draw_food()
{
    if (food)
        random(foodx, foody);
    food = false;
    glColor3f(1.0, 1.0, 0.0);
    glBegin(GL_QUADS);
    glVertex2d(foodx, foody);
    glVertex2d(foodx + 1, foody);
    glVertex2d(foodx + 1, foody + 1);
    glVertex2d(foodx, foody + 1);
    glEnd();
}

void random(int& _min, int& _max)
{


    srand(time(NULL));
    int a = 0, b = 0;
    a = gridx - 2;
    b = gridy - 2;
    int m = 1;

    _min = m + rand() % (a - m);
    _max = m + rand() % (b - m);

}

void init()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
}

//Callbacks
void display_callback()
{
    glClear(GL_COLOR_BUFFER_BIT); //we are clearing color for every buffer so that our screen should get color what we set in init() function
    if (df == 10)
        frontscreen();

    else  if (df == 0)
        startscreen();
    else if (df == 1)
    {

        draw_grid();
        draw_snake();
        draw_food();
        if (game_over)
        {
            string fscore;
            string tmp = to_string(score);
            string text = "Your score : " + tmp;
            int n = text.length();
            char char_array[n + 1];
            strcpy(char_array, text.c_str());
            MessageBox(NULL, char_array, "Game Over", MB_OK);
            exit(0);

        }
    }

    else if (df == 2)
        instructions();
    else if (df == 3)
    {
        exit(0);
    }
    glFlush();
    glutSwapBuffers();// swap the buffers as we used double buffer mode

}

void reshape_callback(int w, int h)
{
    glViewport(0, 0, (GLsizei)w, (GLsizei)h); //view port is the area in which objects are drawn
    glMatrixMode(GL_PROJECTION); // for setting projection we need to be in projection mode
    glLoadIdentity(); //this make sure that no changes are made to matrix

    gluOrtho2D(0, COLUMNS, 0, ROWS); //set projection-mapping column*row coordinate system in our window

    glMatrixMode(GL_MODELVIEW); //setting back to model view
    glLoadIdentity();
}
void timer_callback(int)
{
    glutPostRedisplay();
    glutTimerFunc(1000 / fps, timer_callback, 0);
}
void keyboard_callback(int key, int x, int y)
{
    switch (key)
    {
    case GLUT_KEY_UP:
        if (sDirection != DOWN)
            sDirection = UP;
        break;
    case GLUT_KEY_DOWN:
        if (sDirection != UP)
            sDirection = DOWN;
        break;
    case GLUT_KEY_RIGHT:
        if (sDirection != LEFT)
            sDirection = RIGHT;
        break;
    case GLUT_KEY_LEFT:
        if (sDirection != RIGHT)
            sDirection = LEFT;
        break;
    }
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);//Initializing GLUT
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);//Initializing Display Mode
    glutInitWindowSize(glutGet(GLUT_SCREEN_WIDTH), glutGet(GLUT_SCREEN_HEIGHT) - 100);// opens window at max w,h
    glutCreateWindow("SNAKE");//Name of window
    glutDisplayFunc(display_callback);//sets display callback for current window
    glutReshapeFunc(reshape_callback);//mainly used for setting view port and projection in reshape_callback
    glutSpecialFunc(keyboard_callback);
    glutKeyboardFunc(keyboard);
    glutTimerFunc(0, timer_callback, 0);
    init();//initialization function
    glutMainLoop(); //all the processing will start by calling this line,it holds window on screen
    return 0;
}