doc/html/triangle3d_8h_source.html

00001 // Copyright (C) 2002-2012 Nikolaus Gebhardt
-00002 // This file is part of the "Irrlicht Engine".
-00003 // For conditions of distribution and use, see copyright notice in irrlicht.h
-00004
-00005 #ifndef __IRR_TRIANGLE_3D_H_INCLUDED__
-00006 #define __IRR_TRIANGLE_3D_H_INCLUDED__
-00007
-00008 #include "vector3d.h"
-00009 #include "line3d.h"
-00010 #include "plane3d.h"
-00011 #include "aabbox3d.h"
-00012
-00013 namespace irr
-00014 {
-00015 namespace core
-00016 {
-00017
-00019     template <class T>
-00020     class triangle3d
-00021     {
-00022     public:
-00023
-00025         triangle3d() {}
-00027         triangle3d(vector3d<T> v1, vector3d<T> v2, vector3d<T> v3) : pointA(v1), pointB(v2), pointC(v3) {}
-00028
-00030         bool operator==(const triangle3d<T>& other) const
-00031         {
-00032             return other.pointA==pointA && other.pointB==pointB && other.pointC==pointC;
-00033         }
-00034
-00036         bool operator!=(const triangle3d<T>& other) const
-00037         {
-00038             return !(*this==other);
-00039         }
-00040
-00042
-00044         bool isTotalInsideBox(const aabbox3d<T>& box) const
-00045         {
-00046             return (box.isPointInside(pointA) &&
-00047                 box.isPointInside(pointB) &&
-00048                 box.isPointInside(pointC));
-00049         }
-00050
-00052
-00054         bool isTotalOutsideBox(const aabbox3d<T>& box) const
-00055         {
-00056             return ((pointA.X > box.MaxEdge.X && pointB.X > box.MaxEdge.X && pointC.X > box.MaxEdge.X) ||
-00057
-00058                 (pointA.Y > box.MaxEdge.Y && pointB.Y > box.MaxEdge.Y && pointC.Y > box.MaxEdge.Y) ||
-00059                 (pointA.Z > box.MaxEdge.Z && pointB.Z > box.MaxEdge.Z && pointC.Z > box.MaxEdge.Z) ||
-00060                 (pointA.X < box.MinEdge.X && pointB.X < box.MinEdge.X && pointC.X < box.MinEdge.X) ||
-00061                 (pointA.Y < box.MinEdge.Y && pointB.Y < box.MinEdge.Y && pointC.Y < box.MinEdge.Y) ||
-00062                 (pointA.Z < box.MinEdge.Z && pointB.Z < box.MinEdge.Z && pointC.Z < box.MinEdge.Z));
-00063         }
-00064
-00066
-00068         core::vector3d<T> closestPointOnTriangle(const core::vector3d<T>& p) const
-00069         {
-00070             const core::vector3d<T> rab = line3d<T>(pointA, pointB).getClosestPoint(p);
-00071             const core::vector3d<T> rbc = line3d<T>(pointB, pointC).getClosestPoint(p);
-00072             const core::vector3d<T> rca = line3d<T>(pointC, pointA).getClosestPoint(p);
-00073
-00074             const T d1 = rab.getDistanceFrom(p);
-00075             const T d2 = rbc.getDistanceFrom(p);
-00076             const T d3 = rca.getDistanceFrom(p);
-00077
-00078             if (d1 < d2)
-00079                 return d1 < d3 ? rab : rca;
-00080
-00081             return d2 < d3 ? rbc : rca;
-00082         }
-00083
-00085         /*
-00086         \param p Point to test. Assumes that this point is already
-00087         on the plane of the triangle.
-00088         \return True if the point is inside the triangle, otherwise false. */
-00089         bool isPointInside(const vector3d<T>& p) const
-00090         {
-00091             vector3d<f64> af64((f64)pointA.X, (f64)pointA.Y, (f64)pointA.Z);
-00092             vector3d<f64> bf64((f64)pointB.X, (f64)pointB.Y, (f64)pointB.Z);
-00093             vector3d<f64> cf64((f64)pointC.X, (f64)pointC.Y, (f64)pointC.Z);
-00094             vector3d<f64> pf64((f64)p.X, (f64)p.Y, (f64)p.Z);
-00095             return (isOnSameSide(pf64, af64, bf64, cf64) &&
-00096                 isOnSameSide(pf64, bf64, af64, cf64) &&
-00097                 isOnSameSide(pf64, cf64, af64, bf64));
-00098         }
-00099
-00101
-00108         bool isPointInsideFast(const vector3d<T>& p) const
-00109         {
-00110             const vector3d<T> a = pointC - pointA;
-00111             const vector3d<T> b = pointB - pointA;
-00112             const vector3d<T> c = p - pointA;
-00113
-00114             const f64 dotAA = a.dotProduct( a);
-00115             const f64 dotAB = a.dotProduct( b);
-00116             const f64 dotAC = a.dotProduct( c);
-00117             const f64 dotBB = b.dotProduct( b);
-00118             const f64 dotBC = b.dotProduct( c);
-00119
-00120             // get coordinates in barycentric coordinate system
-00121             const f64 invDenom =  1/(dotAA * dotBB - dotAB * dotAB);
-00122             const f64 u = (dotBB * dotAC - dotAB * dotBC) * invDenom;
-00123             const f64 v = (dotAA * dotBC - dotAB * dotAC ) * invDenom;
-00124
-00125             // We count border-points as inside to keep downward compatibility.
-00126             // Rounding-error also needed for some test-cases.
-00127             return (u > -ROUNDING_ERROR_f32) && (v >= 0) && (u + v < 1+ROUNDING_ERROR_f32);
-00128
-00129         }
-00130
-00131
-00133
-00136         bool getIntersectionWithLimitedLine(const line3d<T>& line,
-00137             vector3d<T>& outIntersection) const
-00138         {
-00139             return getIntersectionWithLine(line.start,
-00140                 line.getVector(), outIntersection) &&
-00141                 outIntersection.isBetweenPoints(line.start, line.end);
-00142         }
-00143
-00144
-00146
-00154         bool getIntersectionWithLine(const vector3d<T>& linePoint,
-00155             const vector3d<T>& lineVect, vector3d<T>& outIntersection) const
-00156         {
-00157             if (getIntersectionOfPlaneWithLine(linePoint, lineVect, outIntersection))
-00158                 return isPointInside(outIntersection);
-00159
-00160             return false;
-00161         }
-00162
-00163
-00165
-00169         bool getIntersectionOfPlaneWithLine(const vector3d<T>& linePoint,
-00170             const vector3d<T>& lineVect, vector3d<T>& outIntersection) const
-00171         {
-00172             // Work with f64 to get more precise results (makes enough difference to be worth the casts).
-00173             const vector3d<f64> linePointf64(linePoint.X, linePoint.Y, linePoint.Z);
-00174             const vector3d<f64> lineVectf64(lineVect.X, lineVect.Y, lineVect.Z);
-00175             vector3d<f64> outIntersectionf64;
-00176
-00177             core::triangle3d<irr::f64> trianglef64(vector3d<f64>((f64)pointA.X, (f64)pointA.Y, (f64)pointA.Z)
-00178                                         ,vector3d<f64>((f64)pointB.X, (f64)pointB.Y, (f64)pointB.Z)
-00179                                         , vector3d<f64>((f64)pointC.X, (f64)pointC.Y, (f64)pointC.Z));
-00180             const vector3d<irr::f64> normalf64 = trianglef64.getNormal().normalize();
-00181             f64 t2;
-00182
-00183             if ( core::iszero ( t2 = normalf64.dotProduct(lineVectf64) ) )
-00184                 return false;
-00185
-00186             f64 d = trianglef64.pointA.dotProduct(normalf64);
-00187             f64 t = -(normalf64.dotProduct(linePointf64) - d) / t2;
-00188             outIntersectionf64 = linePointf64 + (lineVectf64 * t);
-00189
-00190             outIntersection.X = (T)outIntersectionf64.X;
-00191             outIntersection.Y = (T)outIntersectionf64.Y;
-00192             outIntersection.Z = (T)outIntersectionf64.Z;
-00193             return true;
-00194         }
-00195
-00196
-00198
-00199         vector3d<T> getNormal() const
-00200         {
-00201             return (pointB - pointA).crossProduct(pointC - pointA);
-00202         }
-00203
-00205
-00210         bool isFrontFacing(const vector3d<T>& lookDirection) const
-00211         {
-00212             const vector3d<T> n = getNormal().normalize();
-00213             const f32 d = (f32)n.dotProduct(lookDirection);
-00214             return F32_LOWER_EQUAL_0(d);
-00215         }
-00216
-00218         plane3d<T> getPlane() const
-00219         {
-00220             return plane3d<T>(pointA, pointB, pointC);
-00221         }
-00222
-00224         T getArea() const
-00225         {
-00226             return (pointB - pointA).crossProduct(pointC - pointA).getLength() * 0.5f;
-00227
-00228         }
-00229
-00231         void set(const core::vector3d<T>& a, const core::vector3d<T>& b, const core::vector3d<T>& c)
-00232         {
-00233             pointA = a;
-00234             pointB = b;
-00235             pointC = c;
-00236         }
-00237
-00239         vector3d<T> pointA;
-00240         vector3d<T> pointB;
-00241         vector3d<T> pointC;
-00242
-00243     private:
-00244         // Using f64 instead of <T> to avoid integer overflows when T=int (maybe also less floating point troubles).
-00245         bool isOnSameSide(const vector3d<f64>& p1, const vector3d<f64>& p2,
-00246             const vector3d<f64>& a, const vector3d<f64>& b) const
-00247         {
-00248             vector3d<f64> bminusa = b - a;
-00249             vector3d<f64> cp1 = bminusa.crossProduct(p1 - a);
-00250             vector3d<f64> cp2 = bminusa.crossProduct(p2 - a);
-00251             f64 res = cp1.dotProduct(cp2);
-00252             if ( res < 0 )
-00253             {
-00254                 // This catches some floating point troubles.
-00255                 // Unfortunately slightly expensive and we don't really know the best epsilon for iszero.
-00256                 vector3d<f64> cp1 = bminusa.normalize().crossProduct((p1 - a).normalize());
-00257                 if (    core::iszero(cp1.X, (f64)ROUNDING_ERROR_f32)
-00258                     &&  core::iszero(cp1.Y, (f64)ROUNDING_ERROR_f32)
-00259                     &&  core::iszero(cp1.Z, (f64)ROUNDING_ERROR_f32) )
-00260                 {
-00261                     res = 0.f;
-00262                 }
-00263             }
-00264             return (res >= 0.0f);
-00265         }
-00266     };
-00267
-00268
-00270     typedef triangle3d<f32> triangle3df;
-00271
-00273     typedef triangle3d<s32> triangle3di;
-00274
-00275 } // end namespace core
-00276 } // end namespace irr
-00277
-00278 #endif
-00279
-