/*  

In this lab, we will consider the viewing transformation, the modeling transformation,
and the projection transformation.

Answer the questions below, the answers will be discussed in lecture.

  1.  Compile and run this code.
  2.  Does the image look 3-dimensional?  Why?
NO, using Orthogonal projection, and looking right down the z-axis at the cube, plus
there is a glLoadIdentity()


  3.  Minimize the output window, and then maximize it.  Does the image change?
  Do you expect it to?
No, it doesn't change.  There is no reshape function, so the its just the default.


  4.  Comment out the	glLoadIdentity();	in	display()	and recompile.
  5.  Now, minimize and maximize the window a few times.  If the camera is moving back
  after each min and max, why doesn't the image "move away" from us?
Cause its Orthographic projection, no sense of distance.



  6.  Comment out the	glOrtho()	in	reshape()	and uncomment the	glFrustum() .
  The		glLoadIdentity();	in	display()	should still be commented.  Recompile.
  7.  Minimize the output window, and then maximize it.  Does the image change?
  Do you expect it to?
The image disappears, since it moves out of the clipping volume.  The GluLookAt is like
a translation.



  8.  Uncomment the		glLoadIdentity();	in	display()	and recompile.
  9.  Minimize the output window, and then maximize it, and confirm that the output
  doesn't change.
  10.  Replace the call to	gluLookAt()		in	display()	with  glTranslatef( , , );
  Fill in the parameters so that it functions the same as the gluLookAt call.  What
  parameters did you use, and why did they work?



  11.  Uncomment the	glScale();	in	display()	and recompile.  What changes? 


*/
#include <GL/glut.h>
#include <cstdlib>

void myInit ()
{
	glClearColor(1.0 , 1.0 , 1.0 , 1.0);
}

void display ()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(0.0 , 0.0 , 0.0);

	glLoadIdentity();

	// Viewing (NOT Viewport) transformation
	//gluLookAt(0.0 , 0.0 , 5.0 , 0.0 , 0.0 , 0.0 , 0.0 , 1.0 , 0.0);
	glTranslatef( 0 , 0 , -5 );

	// Modeling transformation
	glScalef(1.0 , 2.0 , 1.0);

	glutWireCube(1.0);
	glFlush();
}

void reshape (GLint w, GLint h)
{
	glViewport(0,0,w,h);
	glMatrixMode(GL_PROJECTION);

	glLoadIdentity();

	// Projection transformation
	//glOrtho(-1.0,1.0,-1.0,1.0,0,100);
	glFrustum(-1.0,1.0,-1.0,1.0,1.5,20.0);

	glMatrixMode(GL_MODELVIEW);
}

void keyboard (unsigned char key , int x, int y)
{
if ( key=='q' || key=='Q' ) {
		exit( 0 );
	}
}

int main( int argc, char** argv )
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(500,500);
	glutInitWindowPosition(100,100);
	glutCreateWindow(argv[0]);
	myInit();
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyboard);
	glutMainLoop();
	return 0;
}