#include "noises.h"
#include "filterwidth.h"

//! Macro
/**
* A macro to normalize a given value to a specified range.
* \param mi - the minimum value of the range
* \param mx - the maximum value of the range
* \param value - the value to be normalized
* \return the normalized value
*/
#define normalizeRange(mi,mx,value) (value-mi)/(mx-mi)


//! The Bark2 Shader
/**
* This file contains the Bark_Texture displacement shader. 
* @author Hannes Ricklefs - NCCA 2005
*/

//! The displacement shader
/**
* This displacement shader provides the basic functionality to create
* a Photorealistic looking Treebark based on a given texture file.It is 
* more seen as a prove of concept!
* After the texture file has been applied and the turbulence has been adjusted the user should use the 
* provided normalrange.pl script to identify the range of displacement this pattern generates. 
* The resulting min and max values should be passed into lowNormaliseRange and topNormaliseRange respectively.
*
* Inputs
* \param dispScale		- the Scale factor for the texture.
* \param texname 		- the path and name of the texture file.
* \param space 			- the space in which the shader should be be applied
* \param turboctaves 	- the octaves of the Turbulence in order to add turbulence to the overall texture.
* \param turblcunarity 	- the lacunarity of the Turbulence in order to add turbulence to the overall texture.
* \param turbgain	 	- the gain of the Turbulence in order to add turbulence to the overall texture.
* \param lowNormaliseRange - the min value calculated by the displacement inorder to normalise the output hump.
*							.The normlrange.pl script should be used to calculate the min value.
* \param topNormaliseRange - the max value calculated by the displacement inorder to normalise the output hump.
*							.The normlrange.pl script should be used to calculate the max value.
* 
* Outputs:
* \param hump			- the displacement normalise according to lowNormaliseRange and topNormaliseRange
*
*/
displacement Bark_Texture (float dispScale=0.04;
							string texname="",
							space="shader";
							float trueDisp=1,
							turboctaves=4,
							turblac=2,
							turbgain=0.5,
							lowNormaliseRange=0.300805, 
							topNormaliseRange=2.037044;
							output varying float hump = 0;) {
	//standard shader initialisation					
	normal NN = normalize(N);
	point PP = transform(space,P);
	
	//Apply the texture file
	if(texname != "") {
		hump = (float texture(texname,s,t))+ turbulence(PP,filterwidthp(PP),turboctaves,turblac,turbgain);
		
	}
	//printf ("%f\n",hump);
	
	PP=P+NN*hump*dispScale;
	
	N=calculatenormal(PP);
	
	//if ture displacement is selected
	if(trueDisp) 
		P=PP;
	
	//normalise the hump value
	hump = normalizeRange(lowNormaliseRange,topNormaliseRange,hump);

}