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         Scalar intersectRay(const Ray<2>& ray, Ray<2>::Intersection& intersection)
  53         {
  54                 // solve: Cx + r*Dx = Ax + s(Bx - Ax)
  55                 //        Cy + r*Dy = Ay + s(By - Ay)
  56                 // where: 0 <= s <= 1 if intersection
  57                 // given: A = a
  58                 //        B = b
  59                 //        C = ray.point
  60                 //        D = ray.direction
  61
  62                 Scalar denom = ray.direction[0] * (b[1] - a[1]) +
  63                                            ray.direction[1] * (a[0] - b[0]);
  64
  65                 // check if the ray and line are parallel
  66                 if (isEqual(denom, SCALAR(0.0)))
  67                 {
  68                         Scalar numer = a[0] * (ray.point[1] - b[1]) +
  69                                                    b[0] * (a[1] - ray.point[1]) +
  70                                                    ray.point[0] * (b[1] - a[1]);
  71
  72                         // check if they are collinear
  73                         if (isEqual(numer, SCALAR(0.0)))
  74                         {
  75                                 intersection.point = ray.point;
  76                                 intersection.normal.set(0.0, 0.0);
  77                                 return SCALAR(0.0);
  78                         }
  79
  80                         return SCALAR(-1.0);
  81                 }
  82
  83                 Scalar s = (ray.direction[0] * (ray.point[1] - a[1]) +
  84                                         ray.direction[1] * (a[0] - ray.point[0])) / denom;
  85
  86                 // check if the ray hits the segment
  87                 if (s < SCALAR(0.0) || s > SCALAR(1.0)) return SCALAR(-1.0);
  88
  89                 Scalar r = -(a[0] * (ray.point[1] - b[1]) +
  90                                          b[0] * (a[1] - ray.point[1]) +
  91                                          ray.point[0] * (b[1] - a[1])) / denom;
  92
  93                 // make sure we're dealing with the right side of the ray
  94                 if (r < SCALAR(0.0)) return SCALAR(-1.0);
  95
  96                 intersection.point = ray.point + r * ray.direction;
  97
  98                 // gotta use the correct normal
  99                 Vector n = cml::perp(a - b);
 100                 if (cml::dot(a - ray.point, n) < 0) intersection.normal = n;
 101                 else                                intersection.normal = -n;
 102
 103                 return r;
 104         }
 105
 106         void draw(Scalar alpha = 0.0) const
 107         {
 108                 Mf::Texture::resetBind();
 109                 glBegin(GL_LINES);
 110                         glVertex(a);
 111                         glVertex(b);
 112                 glEnd();
 113         }
 114 };
 115
 116
 117 template <int D, int N>
 118 struct Polygon : public Shape<D>
 119 {
 120         typedef cml::vector< Scalar, cml::fixed<D> > Vector;
 121
 122         Vector  points[N];
 123 };
 124
 125
 126 } // namespace Mf
 127
 128 #endif // _MOOF_LINE_HH_
 129
 130 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 131