source/maths/Frustum.h

   1 /* Copyright (C) 2021 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * CFrustum is a collection of planes which define a viewing space.
  20  */
  21
  22 /*
  23 Usually associated with the camera, there are 6 planes which define the
  24 view pyramid. But we allow more planes per frustum which may be used for
  25 portal rendering, where a portal may have 3 or more edges.
  26 */
  27
  28 #ifndef INCLUDED_FRUSTUM
  29 #define INCLUDED_FRUSTUM
  30
  31 #include "maths/Plane.h"
  32
  33 class CBoundingBoxAligned;
  34 class CMatrix3D;
  35
  36 class CFrustum
  37 {
  38 public:
  39         CFrustum();
  40         ~CFrustum();
  41
  42         // Set the number of planes to use for calculations. This is clamped to
  43         // [0, MAX_NUM_FRUSTUM_PLANES].
  44         void SetNumPlanes(size_t num);
  45
  46         size_t GetNumPlanes() const { return m_NumPlanes; }
  47
  48         void AddPlane(const CPlane& plane);
  49
  50         void Transform(const CMatrix3D& m);
  51
  52         // The following methods return true if the shape is
  53         // partially or completely in front of the frustum planes.
  54         bool IsPointVisible(const CVector3D& point) const;
  55         bool DoesSegmentIntersect(const CVector3D& start, const CVector3D& end) const;
  56         bool IsSphereVisible(const CVector3D& center, float radius) const;
  57         bool IsBoxVisible(const CVector3D& position, const CBoundingBoxAligned& bounds) const;
  58         bool IsBoxVisible(const CBoundingBoxAligned& bounds) const;
  59
  60         CPlane& operator[](size_t idx) { return m_Planes[idx]; }
  61         const CPlane& operator[](size_t idx) const { return m_Planes[idx]; }
  62
  63 private:
  64         static const size_t MAX_NUM_FRUSTUM_PLANES = 10;
  65
  66         CPlane m_Planes[MAX_NUM_FRUSTUM_PLANES];
  67         size_t m_NumPlanes;
  68 };
  69
  70 #endif // INCLUDED_FRUSTUM