dep/src/g3dlite/Plane.cpp

   1 /**
   2  @file Plane.cpp
   3
   4  @maintainer Morgan McGuire, matrix@graphics3d.com
   5
   6  @created 2003-02-06
   7  @edited  2006-01-29
   8  */
   9
  10 #include "G3D/platform.h"
  11 #include "G3D/format.h"
  12 #include "G3D/Plane.h"
  13 #include "G3D/stringutils.h"
  14
  15 namespace G3D {
  16
  17 Plane::Plane(
  18     Vector4      point0,
  19     Vector4      point1,
  20     Vector4      point2) {
  21
  22     debugAssertM(
  23         point0.w != 0 ||
  24         point1.w != 0 ||
  25         point2.w != 0,
  26         "At least one point must be finite.");
  27
  28     // Rotate the points around so that the finite points come first.
  29
  30     while ((point0.w == 0) &&
  31            ((point1.w == 0) || (point2.w != 0))) {
  32         Vector4 temp = point0;
  33         point0 = point1;
  34         point1 = point2;
  35         point2 = temp;
  36     }
  37
  38     Vector3 dir1;
  39     Vector3 dir2;
  40
  41     if (point1.w == 0) {
  42         // 1 finite, 2 infinite points; the plane must contain
  43         // the direction of the two direcitons
  44         dir1 = point1.xyz();
  45         dir2 = point2.xyz();
  46     } else if (point2.w != 0) {
  47         // 3 finite points, the plane must contain the directions
  48         // betwseen the points.
  49         dir1 = point1.xyz() - point0.xyz();
  50         dir2 = point2.xyz() - point0.xyz();
  51     } else {
  52         // 2 finite, 1 infinite point; the plane must contain
  53         // the direction between the first two points and the
  54         // direction of the third point.
  55         dir1 = point1.xyz() - point0.xyz();
  56         dir2 = point2.xyz();
  57     }
  58
  59     _normal   = dir1.cross(dir2).direction();
  60     _distance = _normal.dot(point0.xyz());
  61 }
  62
  63
  64 Plane::Plane(
  65     const Vector3&      point0,
  66     const Vector3&      point1,
  67     const Vector3&      point2) {
  68
  69     _normal   = (point1 - point0).cross(point2 - point0).direction();
  70     _distance = _normal.dot(point0);
  71 }
  72
  73
  74 Plane::Plane(
  75     const Vector3&      __normal,
  76     const Vector3&      point) {
  77
  78     _normal   = __normal.direction();
  79     _distance  = _normal.dot(point);
  80 }
  81
  82
  83 Plane Plane::fromEquation(float a, float b, float c, float d) {
  84     Vector3 n(a, b, c);
  85     float magnitude = n.magnitude();
  86     d /= magnitude;
  87     n /= magnitude;
  88     return Plane(n, -d);
  89 }
  90
  91
  92 void Plane::flip() {
  93     _normal   = -_normal;
  94     _distance  = -_distance;
  95 }
  96
  97
  98 void Plane::getEquation(Vector3& n, float& d) const {
  99     double _d;
 100     getEquation(n, _d);
 101     d = (float)_d;
 102 }
 103
 104 void Plane::getEquation(Vector3& n, double& d) const {
 105     n = _normal;
 106     d = -_distance;
 107 }
 108
 109
 110 void Plane::getEquation(float& a, float& b, float& c, float& d) const {
 111     double _a, _b, _c, _d;
 112     getEquation(_a, _b, _c, _d);
 113     a = (float)_a;
 114     b = (float)_b;
 115     c = (float)_c;
 116     d = (float)_d;
 117 }
 118
 119 void Plane::getEquation(double& a, double& b, double& c, double& d) const {
 120     a = _normal.x;
 121     b = _normal.y;
 122     c = _normal.z;
 123     d = -_distance;
 124 }
 125
 126
 127 std::string Plane::toString() const {
 128     return format("Plane(%g, %g, %g, %g)", _normal.x, _normal.y, _normal.z, _distance);
 129 }
 130
 131 }