#pragma once
#include "material.hpp"

/*!
\brief A procedural material.
*/
class WoodMaterial :
	public Material
{
	Vector kinks[20];
public:

	WoodMaterial()
		:Material(Vector(0.7f, 0.5f, 0.3f), Vector(0.2f, 0.2f, 0.2f), 4.0f)
	{
		for(int k=0; k<20; k++)
			kinks[k] = Vector(20.0f - 40.0f * rand() / RAND_MAX, -15.5f - 4.0f * rand() / RAND_MAX, 15.0f - 20.0f * rand() / RAND_MAX);
	}

	Vector getProceduralDiffuseBrdf(const Vector& atPoint) const
	{
		float x2 = atPoint.x * atPoint.x;
		float y2 = atPoint.y * atPoint.y;
		float d = sqrtf(x2 + y2) * 6.0f;
		for(int k=0; k < 20; k++)
		{
			Vector diff; diff.setDifference(kinks[k], atPoint);
			d *= 1.0f - (1.0f / (diff.norm2() + 1.0f));
		}
		d *= 0.5f;
		float c = 1.0f - (1.0f + cosf(d)) / 2.0f;
		c *= c; //c *= c;
		c = 1.0f - c;
		c *= 0.25f;
		return Vector(0.35f + c, 0.15f + c, c);
	}

	void proceduralScatteringProbability (const Vector& atPoint, const Vector& in, Vector& out, const Vector& normal, Vector& result) const
	{
		float nDotOut = normal * out;
		float nDotIn = - (normal * in);
		if ( nDotOut < 0) {
			result = Vector::RGBBLACK;
			return;
		}
		// add diffuse part
		result = getProceduralDiffuseBrdf(atPoint);
		// add specular using max Phong shading
		Vector idealReflected;
		idealReflected.setIdealReflectedDirection (in, normal);
		float dotProduct = idealReflected* out;
	    if(dotProduct > 0)
		{
			float scale = (float)pow (dotProduct, ns) * (ns + 2.0f) * 0.5f / 3.14159265358979323846f ;
			if(nDotOut > nDotIn)
				scale /= nDotOut;
			else
				scale /= nDotIn;
			result += ks * scale;
		}
		result *= nDotOut;
	}
};