Dogcows Code - chaz/yoink/blob - src/Moof/Line.hh

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
   6
   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
   9
  10    * Redistributions  of  source  code  must retain the above copyright notice,
  11      this list of conditions and the following disclaimer.
  12    * Redistributions  in binary form must reproduce the above copyright notice,
  13      this  list of conditions and the following disclaimer in the documentation
  14      and/or other materials provided with the distribution.
  15
  16  THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  20  FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22  SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23  CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24  OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26
  27 *******************************************************************************/
  28
  29 #ifndef _MOOF_LINE_HH_
  30 #define _MOOF_LINE_HH_
  31
  32 #include <Moof/Drawable.hh>
  33 #include <Moof/Math.hh>
  34 #include <Moof/OpenGL.hh>
  35 #include <Moof/Ray.hh>
  36 #include <Moof/Texture.hh>
  37
  38 #include <Moof/Log.hh>
  39
  40
  41 namespace Mf {
  42
  43
  44 template <int D>
  45 struct Line : public Drawable, public Shape<D>
  46 {
  47         typedef cml::vector< Scalar, cml::fixed<D> > Vector;
  48
  49         Vector  a;
  50         Vector  b;
  51
  52
  53         Line() {}
  54
  55         Line(const Vector& point1, const Vector& point2) :
  56                 a(point1),
  57                 b(point2) {}
  58
  59         Scalar intersectRay(const Ray<2>& ray,
  60                         Ray<2>::Intersection& intersection) const
  61         {
  62                 // solve: Cx + r*Dx = Ax + s(Bx - Ax)
  63                 //        Cy + r*Dy = Ay + s(By - Ay)
  64                 // where: 0 <= s <= 1 if intersection
  65                 // given: A = a
  66                 //        B = b
  67                 //        C = ray.point
  68                 //        D = ray.direction
  69
  70                 Scalar denom = ray.direction[0] * (b[1] - a[1]) +
  71                                            ray.direction[1] * (a[0] - b[0]);
  72
  73                 // check if the ray and line are parallel
  74                 if (isEqual(denom, SCALAR(0.0)))
  75                 {
  76                         Scalar numer = a[0] * (ray.point[1] - b[1]) +
  77                                                    b[0] * (a[1] - ray.point[1]) +
  78                                                    ray.point[0] * (b[1] - a[1]);
  79
  80                         // check if they are collinear
  81                         if (isEqual(numer, SCALAR(0.0)))
  82                         {
  83                                 intersection.point = ray.point;
  84                                 intersection.normal.set(0.0, 0.0);
  85                                 return SCALAR(0.0);
  86                         }
  87
  88                         return SCALAR(-1.0);
  89                 }
  90
  91                 Scalar s = (ray.direction[0] * (ray.point[1] - a[1]) +
  92                                         ray.direction[1] * (a[0] - ray.point[0])) / denom;
  93
  94                 // check if the ray hits the segment
  95                 if (s < SCALAR(0.0) || s > SCALAR(1.0)) return SCALAR(-1.0);
  96
  97                 Scalar r = -(a[0] * (ray.point[1] - b[1]) +
  98                                          b[0] * (a[1] - ray.point[1]) +
  99                                          ray.point[0] * (b[1] - a[1])) / denom;
 100
 101                 // make sure we're dealing with the right side of the ray
 102                 if (r < SCALAR(0.0)) return SCALAR(-1.0);
 103
 104                 intersection.point = ray.point + r * ray.direction;
 105
 106                 // gotta use the correct normal
 107                 Vector n = cml::perp(a - b);
 108                 if (cml::dot(a - ray.point, n) < 0) intersection.normal = n;
 109                 else                                intersection.normal = -n;
 110
 111                 return r;
 112         }
 113
 114         void draw(Scalar alpha = 0.0) const
 115         {
 116                 Mf::Texture::resetBind();
 117                 glBegin(GL_LINES);
 118                         glVertex(a);
 119                         glVertex(b);
 120                 glEnd();
 121         }
 122 };
 123
 124
 125 template <int D, int N>
 126 struct Polygon : public Shape<D>
 127 {
 128         typedef cml::vector< Scalar, cml::fixed<D> > Vector;
 129
 130         Vector  points[N];
 131 };
 132
 133
 134 } // namespace Mf
 135
 136 #endif // _MOOF_LINE_HH_
 137
 138 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 139