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#include "CGLA/Vec3f.h"
#include "CGLA/Quaternion.h"

using namespace std;
using namespace CGLA;

/* CGLA example no. 1:
         Computing a normal from the three vertices
         of a triangle */

void example1()
{
        // Define triangle vertices
        Vec3f p0(10,10,10);
        Vec3f p1(20,10,10);
        Vec3f p2(10,20,10);

        // Compute normal
        Vec3f n = normalize(cross(p1-p0,p2-p0));

        // Vectors can be printed using normal facilities
        cout << n << endl;
}

/* CGLA example no. 2:
         Using spherical coordinates.
*/
void example2()
{
        // Create a null vector
        Vec3f p;
        p.set_spherical(0.955317, 3.1415926f/4.0f , 1);
        cout << " p = " << p << ", p.length() = " << p.length() << endl;
}

void example3()
{
        // Construct a quaternion that rotates the x-axis into the 
        // y-axis.
        Quaternion q;
        q.make_rot(Vec3f(1,0,0), Vec3f(0,1,0));
        
        // Create a 4 by 4 Matrix
        Mat4x4f m = translation_Mat4x4f(Vec3f(1,2,3));

        // Multiply the quaternion rotation onto m.
        m *= q.get_mat4x4f();

        // Create a vector (1,1,1)
        Vec3f p(1);

        // Multiply p onto m as a point. That is we assign 1 to p's w coordinate
        // and then throw away the w coordinate after the transformation.
        Vec3f p2 = m.mul_3D_point(p);

        cout << p2 << endl;
}


void example4()
{
        Vec3f p1(0.8660,.4,-.3);
        Vec3f p2(-0.8660,.4,-.3);
        Vec3f p3(0,.7,-.7141);

        Vec3f n1 = cross(p1,p2);
        Vec3f n2 = cross(p2,p3);
        Vec3f n3 = cross(p3,p1);
        Vec3f n  = normalize(n1+n2+n3);
        cout << n1 << n1.length() << endl
                         << n2 << n2.length() << endl
                         << n3 << n3.length() << endl
                         << dot(n,Vec3f(0,0,1)) << endl;
}

int main()
{
//      example1();
//      example2();
//      example3();
        example4();
}