example.cpp

open gl source code for a nice scenic view which outsources the lighting and shading properties

// basic primitives.
#include <stdlib.h>
#include <GL/glut.h>

    void OnReshape(int w, int h)
   {
   // set the drawable region of the window to the maximum available window size
      glViewport(0,0,w,h);
   
   // set up the projection matrix
      glMatrixMode(GL_PROJECTION);
   
   // clear any previous transform and set to the identity matrix
      glLoadIdentity();
   
   // just use an orthographic projection
      glOrtho(0,12,12,0,-1,1);
   
   // go back to modelview matrix so we can move the objects about
      glMatrixMode(GL_MODELVIEW);
   }

    void OnDraw() {
   
      glClearColor ( 1 , 1 , 1, 1 );
   
   // clear the screen & depth buffer
      glClear(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);
   
   // clear the previous transform
      glLoadIdentity();
   
   //  	GL_POINTS
   //  	GL_LINES
   //  	GL_LINE_LOOP
   // 		GL_LINE_STRIP
   //  	GL_TRIANGLES
   //  	GL_TRIANGLE_STRIP
   //  	GL_TRIANGLE_FAN
   //  	GL_QUADS
   //  	GL_QUAD_STRIP
   //  	GL_POLYGON
   
   
      glBegin(GL_LINES);
   
      glColor3f(0,1,0);
      glVertex3f(3,3,0);
   
      glColor3f(1,0,0);
      glVertex3f(2,10,0);
      glVertex3f(7,12,0);
      glColor3f(0,1,0);
      glVertex3f(5,9,0);
   
      glColor3f(0,0,1);
      glVertex3f(8,7,0);
   	
      glVertex3f(6,12,0);
      glEnd();
   
   // currently we've been drawing to the back buffer, we need
   // to swap the back buffer with the front one to make the image visible
      glutSwapBuffers();
   }


    int main(int argc,char** argv) {
   
   // initialise glut
      glutInit(&argc,argv);
   
   // request a depth buffer, RGBA display mode, and we want double buffering
      glutInitDisplayMode(GLUT_DEPTH|GLUT_RGBA|GLUT_DOUBLE);
   
   // set the initial window size
      glutInitWindowSize(640,480);
   
   // create the window
      glutCreateWindow("A basic primitive example");
   
   // set the function to use to draw our scene
      glutDisplayFunc(OnDraw);
   
   // set the function to handle changes in screen size
      glutReshapeFunc(OnReshape);
   
   // run our custom initialisation
 
     glEnable(GL_DEPTH_TEST);
   // this function runs a while loop to keep the program running.
      glutMainLoop();
      return 0;
   }