shithub: libgraphics

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move the edge function out into libgeometry.

--- a/triangle.c

+++ b/triangle.c

@@ -4,27 +4,6 @@

 #include <geometry.h>

 #include <graphics.h>

-/*

- * comparison of a point p with an edge [e0 e1]

- * p to the right: +

- * p to the left: -

- * p on the edge: 0

- */

-static int

-edgeptcmp(Point e0, Point e1, Point p)

-{

-	Point3 e0p, e01, r;

-

-	p = subpt(p, e0);

-	e1 = subpt(e1, e0);

-	e0p = Vec3(p.x,p.y,0);

-	e01 = Vec3(e1.x,e1.y,0);

-	r = crossvec3(e0p, e01);

-

-	/* clamp to avoid overflow */

-	return fclamp(r.z, -1, 1); /* e0.x*e1.y - e0.y*e1.x */

-}

-

 Triangle

 Trian(int x0, int y0, int x1, int y1, int x2, int y2)

 {

@@ -60,13 +39,4 @@

 	pl[2] = t.p2;

 	fillpoly(dst, pl, nelem(pl), 0, src, sp);

-}

-

-int

-ptintriangle(Point p, Triangle t)

-{

-	/* counter-clockwise check */

-	return edgeptcmp(t.p0, t.p2, p) <= 0 &&

-		edgeptcmp(t.p2, t.p1, p) <= 0 &&

-		edgeptcmp(t.p1, t.p0, p) <= 0;

 }