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geometry.cpp
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geometry.cpp
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#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <list>
#include <GL/glut.h>
#include <math.h>
#include "util.h"
#include "geometry.h"
using namespace std;
double dot(Vec3d e1 , Vec3d e2){
return e1.x*e2.x
+e1.y*e2.y
+e1.z*e2.z;
}
double to_degrees(double radians) {
return (180.0/3.14)*radians;
}
double angle(Vec3d e1 , Vec3d e2) {
double dt = dot(e1,e2);
double mag = e1.len()* e2.len();
if(mag == 0 )
mag = 1;
return to_degrees(acos(dt/mag));
}
Vec3d cross(Vec3d e1 , Vec3d e2){
return Vec3d(e1.y*e2.z - e1.z*e2.y,
e1.z*e2.x - e1.x*e2.z,
e1.x*e2.y - e1.y*e2.x);
}
Vec3d normal(Vertex v1 , Vertex v2,Vertex v3) {
Vec3d e1(v1.x- v2.x,v1.y- v2.y,v1.z - v2.z);
Vec3d e2(v2.x- v3.x,v2.y- v3.y,v2.z- v3.z);
Vec3d n = cross(e1,e2);
n.normalize();
return n;
}