include/geometry/geometricUtilities.h

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/*******************************************************************************
** Copyright (c) 2010 MAK Technologies, Inc.
** All rights reserved.
*******************************************************************************/

#pragma once

#include "geometry/geometryDefines.h"

class DtExtent;
class DtPoint;
class DtDcm;
class Dt3dBoundingVolume;
class DtSphere;
class DtVector;
class DtChord;

// Expand the specified extent to include the extent created by the radius and 
// specified local position.  
// @param extent The extent to expand.
// @param localPosition The position of the new extent.
// @param halfLength The half-length of the heigh/width/length of the cube extent,
//                   of the new extent.  The new extent is a @b cube,
//                   and so the length = width = height.  
//
// @note This is commonly used to create an extent from a bounding sphere, which
// is why the radius is really the half-width/length/height and why those are 
// all equal to each other (cube).
DT_DLL_geometry void DtExpandExtentToIncludeBoundingShere(DtExtent& extent, 
                                          const DtPoint& localPosition,
                                          double halfLength);

// Expand the specified extent to include the extent created by the radius and 
// specified local position.  
//
// @param extent The extent to expand
// @param localBoundingVolume The local bounding volume to place and orient, and 
//        then expand the specified extent by.
// @param worldOrientation The world orientation transformation for the bounding volume.
// @param worldLocation The location, in the world, of the bounding volume.
// 
DT_DLL_geometry void DtExpandExtentToIncludeBoundingVolume(DtExtent& extent, 
   const Dt3dBoundingVolume& localBoundingVolume, 
   const DtDcm& worldOrientation,
   const DtPoint& worldLocation);

// \return The point on the triangle defined by triangleA, triangleB, triangleC
// which is closest to testPoint.
DT_DLL_geometry DtPoint DtClosestPointOnTriangleTo(const DtPoint& testPoint,
                                                   const DtPoint& triangleA,
                                                   const DtPoint& triangleB,
                                                   const DtPoint& triangleC);

// Tests the intersection of a ray with a sphere.
// \return True only if they intersect.
// If they do intersect, t will have the distance along the ray (in meters) 
// where the intersection occurs, and intersectPoint will be the point of 
// intersection.  If a chord is specified, the chord will contain the segment 
// through the sphere where the ray intersects.  
DT_DLL_geometry bool DtIntersectRaySphere(const DtPoint& rayStartPoint,
                                          const DtVector& rayDirection,
                                          const DtSphere& sphere,
                                          double& t, DtPoint& intersectPoint);

DT_DLL_geometry bool DtIntersectRaySphere(const DtPoint& rayStartPoint,
                                          const DtVector& rayDirection,
                                          const DtSphere& sphere,
                                          double& t, DtPoint& intersectPoint, 
                                          DtChord& segmentThroughSphere);


// Returns the bounding radius for a given boundingVolume, in the 
// bounding volume's X-Y plane only (takes into account length and
// width only -- ignores height).  
DT_DLL_geometry double DtBoundingRadiusInXY(const Dt3dBoundingVolume& boundingVolume);

// Same as DtBoundingRadiusInXY(), but it returns the square of the value.
// Faster than DtBoundingRadiusInXY().
DT_DLL_geometry double DtBoundingRadiusInXYSquared(const Dt3dBoundingVolume& boundingVolume);