void init( void )
{
    .
    .
    .
    /* Do all your standard initialization stuff */
    .
    .
    .

    /* Generate a texture to hold your depth map, when you copy it */
    glGenTextures(1, &myDepthTexID);
    glBindTexture(GL_TEXTURE_2D, myDepthTexID);
    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri( GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE );
    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, windowWidth, windowHeight
                 GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
}


void display ( void )
{
    /* get ready to draw from the light */
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPHT_BUFFER_BIT );
    glLoadIdentity();
    gluLookAt(  << the view from the light >> );
    .
    .
    .
    /* put your code to draw your shadow map here */
    .
    .
    .
    .
    /* copy your depth map into a texture */
    glBindTexture( GL_TEXTURE_2D, myDepthTexID );
    glCopyTexSubImage2D( GL_TEXTURE_2D, 0, 0, 0, 0, 0, windowWidth, windowHeight );

    /* get ready to draw from the eye */
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    glLoadIdentity();
    gluLookAt(  << the view from the eye >> );
    . 
    .
    .
    /* put your code to draw your scene from the eye's view here */
    .
    .
    .
	
    /* draw shadow map in the lower right corner */
    DrawTextureInLowerRightCorner( myDepthTexID );

    /* finish your display routine here */
    glutSwapBuffers();
}

   

void DrawTextureInLowerRightCorner( GLuint textureID )
{
	/* code to draw a texture in the lower right corner of the screen */
	glPushAttrib( GL_ALL_ATTRIB_BITS );                             // Save OpenGL state on a stack
	glDisable( GL_DEPTH_TEST );
	glMatrixMode(GL_PROJECTION);                                    // we're setting up a new, 2D, projection matrix
	glPushMatrix();
	glLoadIdentity();
	gluOrtho2D( 0, 1, 0, 1 );                                       // Let the screen go from [0..1] in both x, y
	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();
	glLoadIdentity();                                               // No special modelview matrix for this part
	glDisable(GL_LIGHTING);                                         // Don't want lighting on our corner display
	glEnable(GL_TEXTURE_2D);                                        // But it *is* a texture
	glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );   // We just want to draw on the quad
	glBindTexture( GL_TEXTURE_2D, textureID );                      // This is the texture we want to display
	glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,        // Just draw it, nothing more complex.  If using a
					 GL_NONE );                     // normal texture (not depth map), this isn't necessary
	glColor3f(1,1,1);
	glBegin(GL_QUADS);                                              // Draw a texture in the lower right corner
	glTexCoord2f( 0, 0 ); glVertex2f( 0.8, 0 );                     // ranging from (0.8,0.2) down to (1.0,0.0)
	glTexCoord2f( 1, 0 ); glVertex2f( 1.0, 0 );
	glTexCoord2f( 1, 1 ); glVertex2f( 1.0, 0.2 );
	glTexCoord2f( 0, 1 ); glVertex2f( 0.8, 0.2 );
	glEnd();
	glMatrixMode(GL_PROJECTION);                                    // reset our matrices to how we found them
	glPopMatrix();
	glMatrixMode(GL_MODELVIEW);
	glPopMatrix();
	glPopAttrib( );                                                 // reset (most of) the OpenGL state to how we found it
}