gutil.h

hl2 source code. Do not use it illegal.

/**********************************************************************
 *<
	FILE: gutil.h

	DESCRIPTION: Geometric utility functions

	CREATED BY: Dan Silva

	HISTORY:

 *>	Copyright (c) 1994, All Rights Reserved.
 **********************************************************************/

#ifndef _GUTIL_H 

#define _GUTIL_H


//- BaryCoords-----------------------------------------------------
// Given three points in space forming a triangle (p0,p1,p2), 
// and a fourth point in the plane of that triangle, returns the
// barycentric coords of that point relative to the triangle.

DllExport Point3 BaryCoords(Point3 p0, Point3 p1, Point3 p2, Point3 p);

// Same thing in 2D
DllExport Point3 BaryCoords(Point2 p0, Point2 p1, Point2 p2, Point2 p);



//--RayHitsBox--------------------------------------------------------
// Returns true of the ray pierces the box

DllExport BOOL RayHitsBox(Ray &ray, Box3 &b);


// DistPtToLine ---------------------------------------------------------
// find distance of q from line p0->p1 

DllExport float  DistPtToLine(Point2 *p0, Point2 *p1, Point2 *q );


// Dist3DPtToLine ---------------------------------------------------------
// find distance of q from line p0->p1 

DllExport float  Dist3DPtToLine(Point3* p0, Point3* p1, Point3*  q );


//----------------------------------------------------------------------
// Computing the 3 Bump basis vectors from the UVW's at the triangle.
//
//  input:
//    tv: texture coordinates at 3 triangle vertices
//    v: coordinates of triangle vertices (usually in camera space)
//
// output:
//    bvec: the 3 bump basis vectors (normalized) corresponding to the U,V,and W axes.
//
DllExport void ComputeBumpVectors(const Point3 tv[3], const Point3 v[3], Point3 bvec[3]);



//-------------------------------------------------------------------------------
// Quick and dirty unit vector compression. Only accurate to 1 part in 512
//
ULONG DllExport CompressNormal(Point3 p);

Point3 DllExport DeCompressNormal(ULONG n);

//-------------------------------------------------------------------------------
// JH 10/05/98
// Method to come up with an arbitray axis system given an "up" direction
// Conforms to the AutoCAD algorithm
void DllExport ArbAxis(const Point3& zAxis, Matrix3& matrix);




#endif