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#include <u.h>
#include <libc.h>
#include <geometry.h>
/* 2D */
Point2
Pt2(double x, double y, double w)
{
return (Point2){x, y, w};
}
Point2
Vec2(double x, double y)
{
return (Point2){x, y, 0};
}
Point2
addpt2(Point2 a, Point2 b)
{
return Pt2(a.x+b.x, a.y+b.y, a.w+b.w);
}
Point2
subpt2(Point2 a, Point2 b)
{
return Pt2(a.x-b.x, a.y-b.y, a.w-b.w);
}
Point2
mulpt2(Point2 p, double s)
{
return Pt2(p.x*s, p.y*s, p.w*s);
}
Point2
divpt2(Point2 p, double s)
{
return Pt2(p.x/s, p.y/s, p.w/s);
}
Point2
lerp2(Point2 a, Point2 b, double t)
{
if(t < 0) t = 0;
if(t > 1) t = 1;
return Pt2(
(1 - t)*a.x + t*b.x,
(1 - t)*a.y + t*b.y,
(1 - t)*a.w + t*b.w
);
}
double
dotvec2(Point2 a, Point2 b)
{
return a.x*b.x + a.y*b.y;
}
double
vec2len(Point2 v)
{
return sqrt(dotvec2(v, v));
}
Point2
normvec2(Point2 v)
{
double len;
len = vec2len(v);
if(len == 0)
return Pt2(0,0,0);
return Pt2(v.x/len, v.y/len, 0);
}
/* 3D */
Point3
Pt3(double x, double y, double z, double w)
{
return (Point3){x, y, z, w};
}
Point3
Vec3(double x, double y, double z)
{
return (Point3){x, y, z, 0};
}
Point3
addpt3(Point3 a, Point3 b)
{
return Pt3(a.x+b.x, a.y+b.y, a.z+b.z, a.w+b.w);
}
Point3
subpt3(Point3 a, Point3 b)
{
return Pt3(a.x-b.x, a.y-b.y, a.z-b.z, a.w-b.w);
}
Point3
mulpt3(Point3 p, double s)
{
return Pt3(p.x*s, p.y*s, p.z*s, p.w*s);
}
Point3
divpt3(Point3 p, double s)
{
return Pt3(p.x/s, p.y/s, p.z/s, p.w/s);
}
Point3
lerp3(Point3 a, Point3 b, double t)
{
if(t < 0) t = 0;
if(t > 1) t = 1;
return Pt3(
(1 - t)*a.x + t*b.x,
(1 - t)*a.y + t*b.y,
(1 - t)*a.z + t*b.z,
(1 - t)*a.w + t*b.w
);
}
double
dotvec3(Point3 a, Point3 b)
{
return a.x*b.x + a.y*b.y + a.z*b.z;
}
Point3
crossvec3(Point3 a, Point3 b)
{
return Pt3(
a.y*b.z - a.z*b.y,
a.z*b.x - a.x*b.z,
a.x*b.y - a.y*b.x,
0
);
}
double
vec3len(Point3 v)
{
return sqrt(dotvec3(v, v));
}
Point3
normvec3(Point3 v)
{
double len;
len = vec3len(v);
if(len == 0)
return Pt3(0,0,0,0);
return Pt3(v.x/len, v.y/len, v.z/len, 0);
}
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