From 78e51a8c6678b6e3dff3d619aa786669f531f4bc Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 03:45:44 +0000 Subject: checkpoint --- man/man3/arith3.html | 216 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 216 insertions(+) create mode 100644 man/man3/arith3.html (limited to 'man/man3/arith3.html') diff --git a/man/man3/arith3.html b/man/man3/arith3.html new file mode 100644 index 00000000..71cf815c --- /dev/null +++ b/man/man3/arith3.html @@ -0,0 +1,216 @@ + +arith3(3) - Plan 9 from User Space + + + + +
+
+
ARITH3(3)ARITH3(3) +
+
+

NAME
+ +
+ + add3, sub3, neg3, div3, mul3, eqpt3, closept3, dot3, cross3, len3, + dist3, unit3, midpt3, lerp3, reflect3, nearseg3, pldist3, vdiv3, + vrem3, pn2f3, ppp2f3, fff2p3, pdiv4, add4, sub4 – operations on + 3-d points and planes
+ +
+

SYNOPSIS
+ +
+ + +
+ + #include <draw.h> +
+ + #include <geometry.h> +
+ + Point3 add3(Point3 a, Point3 b) +
+ + Point3 sub3(Point3 a, Point3 b) +
+ + Point3 neg3(Point3 a) +
+ + Point3 div3(Point3 a, double b) +
+ + Point3 mul3(Point3 a, double b) +
+ + int eqpt3(Point3 p, Point3 q) +
+ + int closept3(Point3 p, Point3 q, double eps) +
+ + double dot3(Point3 p, Point3 q) +
+ + Point3 cross3(Point3 p, Point3 q) +
+ + double len3(Point3 p) +
+ + double dist3(Point3 p, Point3 q) +
+ + Point3 unit3(Point3 p) +
+ + Point3 midpt3(Point3 p, Point3 q) +
+ + Point3 lerp3(Point3 p, Point3 q, double alpha) +
+ + Point3 reflect3(Point3 p, Point3 p0, Point3 p1) +
+ + Point3 nearseg3(Point3 p0, Point3 p1, Point3 testp) +
+ + double pldist3(Point3 p, Point3 p0, Point3 p1) +
+ + double vdiv3(Point3 a, Point3 b) +
+ + Point3 vrem3(Point3 a, Point3 b) +
+ + Point3 pn2f3(Point3 p, Point3 n) +
+ + Point3 ppp2f3(Point3 p0, Point3 p1, Point3 p2) +
+ + Point3 fff2p3(Point3 f0, Point3 f1, Point3 f2) +
+ + Point3 pdiv4(Point3 a) +
+ + Point3 add4(Point3 a, Point3 b) +
+ + Point3 sub4(Point3 a, Point3 b)
+ +
+

DESCRIPTION
+ +
+ + These routines do arithmetic on points and planes in affine or + projective 3-space. Type Point3 is
+ +
+ + typedef struct Point3 Point3;
+ struct Point3{
+ +
+ + double x, y, z, w;
+ +
+ };
+ +
+ + +
+ Routines whose names end in 3 operate on vectors or ordinary points + in affine 3-space, represented by their Euclidean (x,y,z) coordinates. + (They assume w=1 in their arguments, and set w=1 in their results.)
+ Name       Description
+ add3       Add the coordinates of two points.
+ sub3       Subtract coordinates of two points.
+ neg3       Negate the coordinates of a point.
+ mul3       Multiply coordinates by a scalar.
+ div3       Divide coordinates by a scalar.
+ eqpt3      Test two points for exact equality.
+ closept3   Is the distance between two points smaller than eps?
+ dot3       Dot product.
+ cross3     Cross product.
+ len3       Distance to the origin.
+ dist3      Distance between two points.
+ unit3      A unit vector parallel to p.
+ midpt3     The midpoint of line segment pq.
+ lerp3      Linear interpolation between p and q.
+ reflect3   The reflection of point p in the segment joining p0 and + p1.
+ nearseg3   The closest point to testp on segment p0 p1.
+ pldist3    The distance from p to segment p0 p1.
+ vdiv3      Vector divide -- the length of the component of a parallel + to b, in units of the length of b.
+ vrem3      Vector remainder -- the component of a perpendicular to b. + Ignoring roundoff, we have eqpt3(add3(mul3(b, vdiv3(a, b)), vrem3(a, + b)), a). +
+ + The following routines convert amongst various representations + of points and planes. Planes are represented identically to points, + by duality; a point p is on a plane q whenever p.x*q.x+p.y*q.y+p.z*q.z+p.w*q.w=0. + Although when dealing with affine points we assume p.w=1, we can’t + make the same + assumption for planes. The names of these routines are extra-cryptic. + They contain an f (for ‘face’) to indicate a plane, p for a point + and n for a normal vector. The number 2 abbreviates the word ‘to.’ + The number 3 reminds us, as before, that we’re dealing with affine + points. Thus pn2f3 takes a point and a normal + vector and returns the corresponding plane.
+ Name       Description
+ pn2f3      Compute the plane passing through p with normal n.
+ ppp2f3     Compute the plane passing through three points.
+ fff2p3     Compute the intersection point of three planes. +
+ + The names of the following routines end in 4 because they operate + on points in projective 4-space, represented by their homogeneous + coordinates.
+ pdiv4Perspective division. Divide p.w into p’s coordinates, converting + to affine coordinates. If p.w is zero, the result is the same + as the argument.
+ add4   Add the coordinates of two points.
+ sub4   Subtract the coordinates of two points.
+ +
+

SOURCE
+ +
+ + /usr/local/plan9/src/libgeometry
+ +
+

SEE ALSO
+ +
+ + matrix(3)
+ +
+ +

 +
+
+ + +
+
+
+Space Glenda +
+
+ + -- cgit v1.2.3