mix.cpp

/*
    pbrt source code Copyright(c) 1998-2010 Matt Pharr and Greg Humphreys.

    This file is part of pbrt.

    pbrt is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.  Note that the text contents of
    the book "Physically Based Rendering" are *not* licensed under the
    GNU GPL.

    pbrt is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

// mix.cpp*
#include "pbrt.h"
#include "texture.h"
#include "paramset.h"
// MixTexture Declarations
template <class T>
class MixTexture : public Texture<T> {
public:
	// MixTexture Public Methods
	MixTexture(Reference<Texture<T> > t1,
			   Reference<Texture<T> > t2,
			   Reference<Texture<float> > amt) {
		tex1 = t1;
		tex2 = t2;
		amount = amt;
	}
	T Evaluate(const DifferentialGeometry &dg) const {
		T t1 = tex1->Evaluate(dg), t2 = tex2->Evaluate(dg);
		float amt = amount->Evaluate(dg);
		return (1.f - amt) * t1 + amt * t2;
	}
private:
	Reference<Texture<T> > tex1, tex2;
	Reference<Texture<float> > amount;
};
// MixTexture Method Definitions
extern "C" DLLEXPORT Texture<float> * CreateFloatTexture(const Transform &tex2world,
		const TextureParams &tp) {
	return new MixTexture<float>(
		tp.GetFloatTexture("tex1", 0.f),
		tp.GetFloatTexture("tex2", 1.f),
		tp.GetFloatTexture("amount", 0.5f));
}

extern "C" DLLEXPORT Texture<Spectrum> * CreateSpectrumTexture(const Transform &tex2world,
		const TextureParams &tp) {
	return new MixTexture<Spectrum>(
		tp.GetSpectrumTexture("tex1", 0.f),
		tp.GetSpectrumTexture("tex2", 1.f),
		tp.GetFloatTexture("amount", 0.5f));
}