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diff --git a/debian/fireflies/fireflies-2.08/libgfx/doc/geom3d.html b/debian/fireflies/fireflies-2.08/libgfx/doc/geom3d.html new file mode 100644 index 00000000..549aa7a7 --- /dev/null +++ b/debian/fireflies/fireflies-2.08/libgfx/doc/geom3d.html @@ -0,0 +1,59 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" + "http://www.w3.org/TR/REC-html40/loose.dtd"> +<!-- $Id: geom3d.html 160 2000-09-05 19:44:15Z garland $ --> + +<html> + +<head> +<title>libgfx: 3-D Geometric Procedures</title> +<link rel=stylesheet href="cdoc.css" type="text/css"> +<meta name="Author" content="Michael Garland"> +</head> + +<body> + +<h2>3-D Geometric Procedures</h2> + +<p>Triangles are a very common modeling primitive in many graphics +applications. The <tt>libgfx</tt> library provides a package of routines for +computing various geometric properties of triangles. +To use this package you must include the standard header file +<pre> + #include <gfx/geom3d.h> +</pre> +Note that all of these functions assume that the corners of the triangle are +listed in <em>counter-clockwise order</em> around the outward pointing normal. + +<p>You can compute the (signed) area of a triangle using the following +function. Note that the area will be negative if the vertices are listed in +clockwise order. +<pre> + double triangle_area(const Vec3&, const Vec3&, const Vec3&); +</pre> + +<p>The following functions compute the plane defined by a triangle, and the +corresponding normal vector. The standard versions always use unit normal +vectors while the "raw" versions will use unscaled normals. +<pre> + Vec3 triangle_normal(const Vec3&, const Vec3&, const Vec3&); + Vec4 triangle_plane(const Vec3&, const Vec3&, const Vec3&); + + Vec3 triangle_raw_normal(const Vec3&, const Vec3&, const Vec3&); + Vec4 triangle_raw_plane(const Vec3&, const Vec3&, const Vec3&); +</pre> + + +<p>For some meshing applications, it may on occasion be necessary to assess +the aspect ratio of a triangle. +<pre> + double triangle_compactness(const Vec3&, const Vec3&, const Vec3&); +</pre> +This function computes the "compactness" of a triangle. The returned value +will be between 0 and 1, with 0 meaning a degenerate (area=0) triangle and 1 +meaning an equilateral triangle. The formula used, originally suggested by +Andre Gueziec, is 4*sqrt(3) * Area / (L1 + L2 + L3) where Li is the squared +length of side <i>i</i> of the triangle. + +</body> + +</html> |