glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glLoadIdentity();	
gluLookAt(0,3,10, 0,0,0, 0,1,0);
Point3 lpos(LightPosition[0],LightPosition[1],LightPosition[2]);
glLightfv( GL_LIGHT1, GL_POSITION, LightPosition );

RenderScene();	// the floor and the shadow caster quad
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
Quad.DrawShadowVolume(lpos);	
glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );


glPushAttrib( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT | GL_POLYGON_BIT | GL_STENCIL_BUFFER_BIT );
glDisable( GL_LIGHTING );	// Turn Off Lighting
glDepthMask( GL_FALSE );	// Turn Off Writing To The Depth-Buffer
glDepthFunc( GL_LEQUAL );
glEnable( GL_STENCIL_TEST );	// Turn On Stencil Buffer Testing
glColorMask( GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE );	// Don't Draw Into The Colour Buffer
glStencilFunc( GL_ALWAYS, 1, 0xFFFFFFFFL );

glFrontFace(GL_CCW);
glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
Quad.DrawShadowVolume(lpos);

glFrontFace(GL_CW);
glStencilOp(GL_KEEP, GL_KEEP, GL_DECR);
Quad.DrawShadowVolume(lpos);

glFrontFace( GL_CCW );
glColorMask( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE );	

//draw a shadowing rectangle covering the entire screen
glColor4f( 0.0f, 0.0f, 0.0f, 0.4f );
glEnable( GL_BLEND );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glStencilFunc( GL_NOTEQUAL, 0, 0xFFFFFFFFL );
glStencilOp( GL_KEEP, GL_KEEP, GL_KEEP );
glPushMatrix();
glLoadIdentity();
glBegin( GL_TRIANGLE_STRIP );
	glVertex3f(-0.1f, 0.1f,-0.10f);
	glVertex3f(-0.1f,-0.1f,-0.10f);
	glVertex3f( 0.1f, 0.1f,-0.10f);
	glVertex3f( 0.1f,-0.1f,-0.10f);
glEnd();
glPopMatrix();
glPopAttrib();


glColor4f(0.7f, 0.4f, 0.0f, 1.0f);	// Set Color To An Orange
glDisable(GL_LIGHTING);		        // Disable Lighting
glDepthMask(GL_FALSE);			// Disable Depth Mask
glColor4f(0.75f, 0.0f, 0.0f, 1.0f);
glPushMatrix();
glTranslatef(LightPosition[0],LightPosition[1],LightPosition[2]);
gluSphere(sphere, 0.1f, 30, 30);        //draw a sphere with the light position
glPopMatrix();
glEnable(GL_LIGHTING);			// Enable Lighting
glDepthMask(GL_TRUE);		

glFlush();	

bool InitGL(void){	glShadeModel(GL_SMOOTH);							// Enable Smooth Shading	glClearColor(0.0f, 0.0f, 0.0f, 0.5f);				// Black Background	glClearDepth(1.0f);									// Depth Buffer Setup	glClearStencil(0);									// Stencil Buffer Setup	glEnable(GL_DEPTH_TEST);							// Enables Depth Testing	glDepthFunc(GL_LEQUAL);								// The Type Of Depth Testing To Do//	glCullFace(GL_BACK);								// Set Culling Face To Back Face//	glEnable(GL_CULL_FACE);								// Enable Culling	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	// Really Nice Perspective Calculations	float LightAmb[] = { 0.2f, 0.2f, 0.2f, 1.0f};				float LightDif[] = { 0.6f, 0.6f, 0.6f, 1.0f};	glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmb);			// Set Light1 Ambience	glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDif);			// Set Light1 Diffuse	glEnable(GL_LIGHTING);	glEnable(GL_LIGHT1);	glEnable(GL_BLEND);	glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);		glClearColor(0.1f, 1.0f, 0.5f, 1.0f);				// Set Clear Color (Greenish Color)	return true;}