Program 5: Write a program to create a scene using OpenGL illumination functions.

PROGRAM 5: LIGHT

·         Header File

·         Render func

·         Handle resize

·         Display

·         Timer

·         Main func

1.      Header File.(gl/glut.h , math.h, windows.h) // REFER 2d 
       link:http://simplifiedopengl.blogspot.in/2016/08/program-3-write-program-to-implement-2d.html

2.      Initialise rendering function for the 2d object// REFER 2d and include the below mentioned effects for 3d

glEnable(GL_COLOR_MATERIAL);

            glEnable(GL_LIGHTING); //Enable lighting

            glEnable(GL_LIGHT0); //Enable light #0

            glEnable(GL_NORMALIZE); //Automatically normalize normals

3.      Create Handle Resize // REFER 2d

4.       Display Function // REFER 2d

void drawScene()

{

    glClearColor(0.0f, 0.0f, 1.0f, 0.0f);//dark blue

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glRotatef(_angle,0.0f,0.0f,1.0f); //rotate object by 30 degree with respect to y-axis

    glTranslatef(0.0f, 0.0f, -10.0f);

GLfloat ambientColor[] = {0.2f, 0.2f, 0.2f, 1.0f}; //Color (0.2, 0.2, 0.2)

       GLfloat light_ambient[] = {1.0, 1.0,1.0,1.0};//producing the color

      glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientColor);

      GLfloat lightPos0[] = {0.0f, 0.0f, 1.0f, 0.0f}; //Positioned at (4, 0, 8)

      glLightfv(GL_LIGHT0, GL_DIFFUSE, light_ambient);

      glLightfv(GL_LIGHT0, GL_POSITION, lightPos0);

    //************************

      //OBJ

//Right face (x = 1.0f), Left face (x = -1.0f), Back face (z = -1.0f), Front face  (z = 1.0f), Bottom face (y = -1.0f), top face(z=1.0f)

glutSwapBuffers();

}

5.      Timer

6.      Main Function

SAMPLE PROGRAM

#include <iostream>

#include <stdlib.h>

#include <GL/glut.h>

using namespace std;

//Initializes 3D rendering

void initRendering() {

            glEnable(GL_DEPTH_TEST);

            glEnable(GL_COLOR_MATERIAL);

            glEnable(GL_LIGHTING); //Enable lighting

            glEnable(GL_LIGHT0); //Enable light #0

            glEnable(GL_NORMALIZE); //Automatically normalize normals

}

void handleResize(int w, int h) {

            glViewport(0, 0, w, h);

            glMatrixMode(GL_PROJECTION);

            glLoadIdentity();

            gluPerspective(45.0, (double)w / (double)h, 1.0, 200.0);

}

float _angle = 0.0f;

//Draws the 3D scene

void drawScene() {

            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            glMatrixMode(GL_MODELVIEW);

            glLoadIdentity();

            glTranslatef(0.0f, 0.0f, -5.0f);

            //Add ambient light

            GLfloat ambientColor[] = {0.2f, 0.2f, 0.2f, 1.0f}; //Color (0.2, 0.2, 0.2)

             GLfloat light_ambient[] = {1.0, 1.0,1.0,1.0};//producing the color

            glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientColor);

            GLfloat lightPos0[] = {0.0f, 0.0f, 1.0f, 0.0f}; //Positioned at (4, 0, 8)

            glLightfv(GL_LIGHT0, GL_DIFFUSE, light_ambient);

            glLightfv(GL_LIGHT0, GL_POSITION, lightPos0);

            glRotatef(_angle, 1.0f,0.0f, 0.0f);

    glColor4f(0.0f, 1.0f, 1.0f, 1.0f);//light blue

    glBegin(GL_QUADS);                // Begin drawing the color cube with 6 quads

      // Top face (y = 1.0f)

      // Define vertices in counter-clockwise (CCW) order with normal pointing out

      glColor3f(0.0f, 1.0f, 0.0f);     // Green

      glVertex3f( 1.0f, 1.0f, -1.0f);

      glVertex3f(-1.0f, 1.0f, -1.0f);

      glVertex3f(-1.0f, 1.0f,  1.0f);

      glVertex3f( 1.0f, 1.0f,  1.0f);

      // Bottom face (y = -1.0f)

    glColor3f(1.0f, 1.0f, 0.0f);     // Yellow

      glVertex3f( 1.0f, -1.0f,  1.0f);

      glVertex3f(-1.0f, -1.0f,  1.0f);

      glVertex3f(-1.0f, -1.0f, -1.0f);

      glVertex3f( 1.0f, -1.0f, -1.0f);

      // Front face  (z = 1.0f)

      glColor3f(1.0f, 0.0f, 0.0f);     // Red

      glVertex3f( 1.0f,  1.0f, 1.0f);

      glVertex3f(-1.0f,  1.0f, 1.0f);

      glVertex3f(-1.0f, -1.0f, 1.0f);

      glVertex3f( 1.0f, -1.0f, 1.0f);

      // Back face (z = -1.0f)

      glColor3f(1.0f, 1.0f, 1.0f);     // Yellow

      glVertex3f( 1.0f, -1.0f, -1.0f);

      glVertex3f(-1.0f, -1.0f, -1.0f);

      glVertex3f(-1.0f,  1.0f, -1.0f);

      glVertex3f( 1.0f,  1.0f, -1.0f);

      // Left face (x = -1.0f)

      glColor3f(0.0f, 0.0f, 1.0f);     // Blue

      glVertex3f(-1.0f,  1.0f,  1.0f);

      glVertex3f(-1.0f,  1.0f, -1.0f);

      glVertex3f(-1.0f, -1.0f, -1.0f);

      glVertex3f(-1.0f, -1.0f,  1.0f);

      // Right face (x = 1.0f)

      glColor3f(1.0f, 0.0f, 1.0f);     // Magenta

      glVertex3f(1.0f,  1.0f, -1.0f);

      glVertex3f(1.0f,  1.0f,  1.0f);

      glVertex3f(1.0f, -1.0f,  1.0f);

      glVertex3f(1.0f, -1.0f, -1.0f);

    glEnd();  // End of drawing color-cube

            glutSwapBuffers();

            glFlush();

}

void update(int value) {

            _angle += 1.5f;

            if (_angle > 360) {

                        _angle -= 360;

            }

            glutPostRedisplay();

            glutTimerFunc(25, update,0);

}

int main(int argc, char** argv) {

            //Initialize GLUT

            glutInit(&argc, argv);

            glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);

            glutInitWindowSize(400, 400);

            glutCreateWindow("Lighting");

            initRendering();

            glutDisplayFunc(drawScene);

            glutReshapeFunc(handleResize);

            glutTimerFunc(25, update, 0); //Add a timer

            glutMainLoop();

            return 0;

}