From 0373255087377122eeb10e006ffb8aa1b57e611c Mon Sep 17 00:00:00 2001
From: rgl <devnull@localhost>
Date: Mon, 3 Feb 2020 22:42:28 +0100
Subject: after a year or so of work, i dare create a proper repo.

---
 libgeometry/point.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 libgeometry/point.c

(limited to 'libgeometry/point.c')

diff --git a/libgeometry/point.c b/libgeometry/point.c
new file mode 100644
index 0000000..657eb4c
--- /dev/null
+++ b/libgeometry/point.c
@@ -0,0 +1,161 @@
+#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 (Point2){a.x+b.x, a.y+b.y, a.w+b.w};
+}
+
+Point2
+subpt2(Point2 a, Point2 b)
+{
+	return (Point2){a.x-b.x, a.y-b.y, a.w-b.w};
+}
+
+Point2
+mulpt2(Point2 p, double s)
+{
+	return (Point2){p.x*s, p.y*s, p.w*s};
+}
+
+Point2
+divpt2(Point2 p, double s)
+{
+	return (Point2){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 (Point2){
+		(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 (Point2){0, 0, 0};
+	return (Point2){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 (Point3){a.x+b.x, a.y+b.y, a.z+b.z, a.w+b.w};
+}
+
+Point3
+subpt3(Point3 a, Point3 b)
+{
+	return (Point3){a.x-b.x, a.y-b.y, a.z-b.z, a.w-b.w};
+}
+
+Point3
+mulpt3(Point3 p, double s)
+{
+	return (Point3){p.x*s, p.y*s, p.z*s, p.w*s};
+}
+
+Point3
+divpt3(Point3 p, double s)
+{
+	return (Point3){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 (Point3){
+		(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 (Point3){
+		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 (Point3){0, 0, 0, 0};
+	return (Point3){v.x/len, v.y/len, v.z/len, 0};
+}
-- 
cgit v1.2.3