/******************************************************************/
/* BRDFMaterial.h                                                 */
/* -----------------------                                        */
/*                                                                */
/* The file defines a simple material class for path tracing.  It */
/*    allows a BRDF class to be passed in.  This class's shade    */
/*    function then samples the BRDF according to it's members    */
/*    and modulates the color by a fired ray.  This class is here */
/*    to make development of new BRDFs easy (so the Shade() func  */
/*    need not be rewritten).                                     */
/*                                                                */
/* Really, if one did a little more design (and perhaps tweaked   */
/*    this class a little more), this would be the ONLY material  */
/*    class needed for your path tracer.                          */
/*                                                                */
/* Note this is NOT tuned for extreme performance.  It is assumed */
/*    it will be running in a batch mode, so it is written with   */
/*    an eye towards maintainability over minor speed bumps.      */
/*                                                                */
/* Chris Wyman (03/30/2007)                                       */
/******************************************************************/

#ifndef BRDFMATERIAL_H
#define BRDFMATERIAL_H

#include "DataTypes/Color.h"
#include "Utils/TextParsing.h"
#include "Core/Ray.h"
#include "Core/RayPacket.h"
#include "Materials/Material.h"
#include "Materials/BRDF.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

class Scene;

class BRDFMaterial : public Material {
	BRDF *brdf;
	bool useExplicitDirectLighting;

	// One of these two functions is called by the shade routine.
	//    (Performance loss: 2 temp copies of the color, this way...)
	Color ImplicitDirectLight( Ray &ray, Scene &scene ) const;
	Color ExplicitDirectLight( Ray &ray, Scene &scene ) const;
public:
	// One can either pass in an existing BRDF.
	BRDFMaterial( BRDF *brdf, bool useExplicitDirectLighting=false ) : 
	    brdf(brdf), useExplicitDirectLighting(useExplicitDirectLighting) {}

	// Or one can read the material from a file.
	BRDFMaterial( FILE *f, Scene *s );

	// This is the shade routine -- it computes color with one of the two
	//     private methods depending on if the scene asks for explicit direct
	//     lighting or the naive (implicit) method.
	virtual Color Shade( Ray &ray, Scene &scene ) const;
};


#endif