textures.c

#include "objects.h"
#include "operations.h"
#include "textures.h"
#include <stdio.h>
#include <math.h>


POINT2D getRectangleTexture(OBJECT obj, POINT intersection){
	POLYGON polygon = obj.polygon;

	POINT p = polygon.rectangle[4];

	double H = getDistance(polygon.points[0], polygon.points[1]);
	double L = getDistance(polygon.points[0], polygon.points[3]);

	VECTOR U;
	U.x = (polygon.points[1].x - polygon.points[0].x)/H;
	U.y = (polygon.points[1].y - polygon.points[0].y)/H;
	U.z = (polygon.points[1].z - polygon.points[0].z)/H;

	VECTOR V;
	V.x = (polygon.points[3].x - polygon.points[0].x)/L;
	V.y = (polygon.points[3].y - polygon.points[0].y)/L;
	V.z = (polygon.points[3].z - polygon.points[0].z)/L;

	VECTOR d;
	d.x = intersection.x - polygon.points[0].x;
	d.y = intersection.y - polygon.points[0].y;
	d.z = intersection.z - polygon.points[0].z;

	POINT2D coord;
	coord.u = pointProduct(d, U)/H;
	coord.v = pointProduct(d, V)/L;


	return coord;
}



POINT2D getCylinderTexture(OBJECT obj, POINT intersection){
	CYLINDER cylinder = obj.cylinder;

	VECTOR d;
	d.x = intersection.x - cylinder.anchor.x;
	d.y = intersection.y - cylinder.anchor.y;
	d.z = intersection.z - cylinder.anchor.z;

//	d = normalizeVector(d);

	double u = acos(pointProduct(getN(obj, intersection), cylinder.G))/(2*PI);

	POINT2D coord;
	coord.v = pointProduct(cylinder.axis, d)/(cylinder.d2 - cylinder.d1);

	PEQUATION eq = cylinder.equation;
	double darkSide = eq.a*intersection.x + eq.b*intersection.y + eq.c*intersection.z + eq.d;

	if(darkSide < 0){
		u = 1 - u;
	}
	coord.u = u;

	return coord;
}

POINT2D getConeTexture(OBJECT obj, POINT intersection){
	CONE cone = obj.cone;

	VECTOR d;
	VECTOR temp;
	POINT2D coord;
	double u;

	d.x = (intersection.x - cone.anchor.x)*cone.axis.x;
	d.y = (intersection.y - cone.anchor.y)*cone.axis.y;
	d.z = (intersection.z - cone.anchor.z)*cone.axis.z;

	coord.v = pointProduct(cone.axis,d)/(cone.d2 - cone.d1);

	temp.x = intersection.x-(cone.anchor.x - d.x*cone.axis.x);
	temp.y = intersection.y-(cone.anchor.y - d.y*cone.axis.y);
	temp.z = intersection.z-(cone.anchor.z - d.z*cone.axis.z);

	double magnitude = getMagnitude(temp);

	u = acosf(temp.x/magnitude)/(2*PI);

	PEQUATION eq = cone.equation;
	double darkSide = eq.a*intersection.x + eq.b*intersection.y + eq.c*intersection.z + eq.d;

	if(darkSide < 0) u = 1 - u;

	coord.u = u;

	return coord;


}


POINT2D getSphereTexture(OBJECT obj, POINT intersection){
	SPHERE sphere = obj.sphere;
	VECTOR norte;
	POINT2D coord;
	VECTOR N;
	VECTOR temp;
	VECTOR greenwich;
	double u,d;

	norte.x = 1;
	norte.y = 0;
	norte.z = 0;

	greenwich.x = 0;
	greenwich.y = 1;
	greenwich.z = 0;


	N = getN(obj,intersection);

	coord.v = acosf(pointProduct(N,norte))/PI;

	d = norte.x * intersection.x + norte.y * intersection.y + norte.z * intersection.z +
			(-(norte.x*intersection.x)-(norte.y*intersection.y)-norte.z*intersection.z);


	temp.x = (intersection.x - d*norte.x) - sphere.center.x;
	temp.y = (intersection.y - d*norte.y) - sphere.center.y;
	temp.z = (intersection.z - d*norte.z) - sphere.center.z;

	double magnitude = getMagnitude(temp);

	u = (temp.x/magnitude)*greenwich.x+(temp.y/magnitude)*greenwich.y+(temp.z/magnitude)*greenwich.z;
	u = acosf(u)/(PI*2);


	VECTOR aux;
	aux = cruxProduct(greenwich,norte);

	d = (aux.x*sphere.center.x + aux.y*sphere.center.y + aux.z*sphere.center.z);
	if(aux.x*intersection.x+aux.y*intersection.y+aux.z*intersection.z + d > 0) u = 1-u;


	coord.u = u;


	return coord;

}