/*
surface shader:
	brick_shiny_building

creator:
	Nick Meshes, DePaul University

description:
	Based on loosely screen.sl and shiny.sl
	Makes a surface that looks like an office building with reflective windows. Walls
	look plastic-like though.
	
parameters:
	Ka, Kd, Ks, roughness, specularcolor - work just like the plastic shader
	wallcolor and windowcolor
	window width and height set
	parts between windows set as well.
	up - x=0, y=1, z=2, building is square in this algorithm
	widthoffset will be between 0 and (windowwidth + wallwidth)
	heightoffset will be between 0 and (windowheight + wallheight)  
	ceiling - top where no more windows exist
	floor - bottom where no more windows exist

*/

#include "rayserver.h"
#include "raytrace.h"
#include "noises.h"
#include "patterns.h"


displacement stucco_building2(
	   float up = 2;
	   float ceiling = 100, floor = -100;
	   float windowwidth = 1, wallwidth = 1;
	   float windowheight = 1, wallheight = 1;
	   float widthoffset = 0, heightoffset = 0;
	   float Kr = 0.5, blur = 0;
	   float samples = 1;

/* stucco features */
	  float freq = 1;
	  float Km = 0.2;
	  float octaves = 3;
	  float trough = -0.15, peak = 0.35;
 )
{
	float xpart, ypart, zpart;
	float sum = 0;
    point Pshad;       /* Point to be shaded, in shader space */
    float fwidth;      /* Estimated change in P between image samples */
    normal NN;         /* Unit length surface normal */
    float disp;        /* Amount to displace */

	if (up == 0){
		xpart = abs(ycomp(P));
		ypart = abs(zcomp(P));
		zpart = abs(xcomp(P));
	}
	else if (up == 1){
		xpart = abs(zcomp(P));
		ypart = abs(xcomp(P));
		zpart = abs(ycomp(P));
	}
	else{
		xpart = abs(xcomp(P));
		ypart = abs(ycomp(P));
		zpart = abs(zcomp(P));
	}

	xpart = mod((xpart + widthoffset), (windowwidth + wallwidth));
	ypart = mod((ypart + widthoffset), (windowwidth + wallwidth));
	zpart = mod((zpart + heightoffset), (windowheight + wallheight));
	
	if (zpart <= floor)
		sum = 1;
	if (zpart >= ceiling)
		sum = 1;
	
	if (xpart > (windowwidth/2))
		if (xpart < (wallwidth + (windowwidth/2))) sum = sum + 1;
	if (ypart > (windowwidth/2))
		if (ypart < (wallwidth + (windowwidth/2))) sum = sum + 1;
	if (zpart > (windowheight/2))
		if (zpart < (wallheight + (windowheight/2))) sum = sum + 1;
	
	if (sum > 0){
    /* Do texture calcs in "shader" space, get approximate filter size */
    Pshad = freq * transform ("shader", P);
    fwidth = filterwidthp(Pshad);

    /* Compute some fractional Brownian motion */
    disp = fBm (Pshad, fwidth, 3, 2, 0.6);
    
    /* Threshold the fBm and scale it */
    disp = Km * smoothstep (trough, peak, disp);

    /* displace in shader space units */
    NN = normalize(N);
    P += NN * (disp / length (ntransform ("shader", NN)));
    N = normalize (calculatenormal(P));
	}
}