onb.cc

// onb.cc

#include "onb.h"

#define ONB_EPSILON 0.01f

// using squaredLength as its faster . . .
void ONB::initFromU( const Vector3& u ) {
    Vector3 n(1.0f, 0.0f, 0.0f);
    Vector3 m(0.0f, 1.0f, 0.0f);
    
    U = unitVector(u);
    V = cross(U, n);
    if (V.squaredLength() < ONB_EPSILON) V = cross(U, m);
    W = cross(U, V);
}

void ONB::initFromV( const Vector3& v ) {
    Vector3 n(1.0f, 0.0f, 0.0f);
    Vector3 m(0.0f, 1.0f, 0.0f);
    
    V = unitVector(v);
    U = cross(V, n);
    if (U.squaredLength() < ONB_EPSILON) U = cross(V, m);
    W = cross(U, V);
}

void ONB::initFromW( const Vector3& w ) {
    Vector3 n(1.0f, 0.0f, 0.0f);
    Vector3 m(0.0f, 1.0f, 0.0f);
    
    W = unitVector(w);
    U = cross(W, n);
    if (U.squaredLength() < ONB_EPSILON) U = cross(W, m);
    V = cross(W, U);
}

void ONB::initFromUV(const Vector3& u, const Vector3& v) {
    U = unitVector(u);
    W = unitVector(cross(u, v));
    V = cross(W, U);
}

void ONB::initFromVU(const Vector3& v, const Vector3& u) {
    V = unitVector(v);
    W = unitVector(cross(u, v));
    U = cross(V, W);
}

void ONB::initFromUW(const Vector3& u, const Vector3& w) {
    U = unitVector(u);
    V = unitVector(cross(w, u));
    W = cross(U, V);
}

void ONB::initFromWU(const Vector3& w, const Vector3& u) {
    W = unitVector(w);
    V = unitVector( cross(w, u));
    U = cross(V, W);
}

void ONB::initFromVW(const Vector3& v, const Vector3& w) {
    V = unitVector(v);
    U = unitVector(cross(v, w));
    W = cross(U, V);
}

void ONB::initFromWV(const Vector3& w, const Vector3& v) {
    W = unitVector(w);
    U = unitVector(cross(v, w));
    V = cross(W, U);
}

bool operator==( const ONB& t1, const ONB& t2)
{ return (t1.u() == t2.u() && t1.v() == t2.v() && t1.w() == t2.w()); }

std::istream& operator>>(std::istream& is, ONB& t) {
    Vector3 tu, tv, tw;
    
    is >> tu >> tv >> tw;
    t.initFromUV(tu, tv);

    // if(tw != t.w()) {
    //     printf("input stream Vector element w %.2f not as expected: %.2f\n", tw, t.w());
    //     exit 1;
    // }
    return is;
}

std::ostream& operator<<(std::ostream& os, const ONB& t) {
    os << t.u() << "\n" << t.v() << "\n" << t.w() << "\n";
    return os;
}