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         bool intersectRay(const Ray<2>& ray, Ray<2>::Intersection& hit) const
  60         {
  61                 // solve: Cx + r*Dx = Ax + s(Bx - Ax)
  62                 //        Cy + r*Dy = Ay + s(By - Ay)
  63                 // where: 0 <= s <= 1 if intersection
  64                 // given: A = a
  65                 //        B = b
  66                 //        C = ray.point
  67                 //        D = ray.direction
  68
  69                 Scalar denom = ray.direction[0] * (b[1] - a[1]) +
  70                                            ray.direction[1] * (a[0] - b[0]);
  71
  72                 // check if the ray and line are parallel
  73                 //if (isEqual(denom, SCALAR(0.0)))
  74                 if (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                                 hit.distance = SCALAR(0.0);
  84                                 hit.normal.set(0.0, 0.0);
  85                                 return true;
  86                         }
  87
  88                         return false;
  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 false;
  96
  97                 hit.distance = -(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                 if (hit.distance < SCALAR(0.0)) return false;
 101
 102                 Vector normal = cml::perp(a - b);
 103                 if (cml::dot(a - ray.point, normal) < 0) hit.normal = normal;
 104                 else                                     hit.normal = -normal;
 105                 return true;
 106         }
 107
 108         void draw(Scalar alpha = 0.0) const
 109         {
 110                 Mf::Texture::resetBind();
 111                 glBegin(GL_LINES);
 112                         glVertex(a);
 113                         glVertex(b);
 114                 glEnd();
 115         }
 116 };
 117
 118
 119 template <int D, int N>
 120 struct Polygon : public Shape<D>
 121 {
 122         typedef cml::vector< Scalar, cml::fixed<D> > Vector;
 123
 124         Vector  points[N];
 125 };
 126
 127
 128 } // namespace Mf
 129
 130 #endif // _MOOF_LINE_HH_
 131
 132 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 133