Pyrogenesis  trunk
HFTracer.h
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1 /* Copyright (C) 2014 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  * Determine intersection of rays with a heightfield.
20  */
21 
22 #ifndef INCLUDED_HFTRACER
23 #define INCLUDED_HFTRACER
24 
25 class CPatch;
26 class CVector3D;
27 class CTerrain;
28 
29 ///////////////////////////////////////////////////////////////////////////////
30 // CHFTracer: a class for determining ray intersections with a heightfield
31 class CHFTracer
32 {
33 public:
34  // constructor; setup data
35  CHFTracer(CTerrain *pTerrain);
36 
37  // intersect ray with this heightfield; return true if intersection
38  // occurs (and fill in grid coordinates and point of intersection), or false otherwise
39  bool RayIntersect(const CVector3D& origin, const CVector3D& dir, int& x, int& z, CVector3D& ipt) const;
40 
41  /**
42  * Intersects ray with a single patch.
43  * The ray is a half-infinite line starting at @p origin with direction @p dir
44  * (not required to be a unit vector).. The patch is treated as a collection
45  * of two-sided triangles, corresponding to the terrain tiles.
46  *
47  * If there is an intersection, returns true; and if @p out is not NULL, it
48  * is set to the intersection point. This is guaranteed to be the earliest
49  * tile intersected (starting at @p origin), but not necessarily the earlier
50  * triangle inside that tile.
51  *
52  * This partly duplicates RayIntersect, but it only operates on a single
53  * patch, and it's more precise (it uses the same tile triangulation as the
54  * renderer), and tries to be more numerically robust.
55  */
56  static bool PatchRayIntersect(CPatch* patch, const CVector3D& origin, const CVector3D& dir, CVector3D* out);
57 
58 private:
59  // test if ray intersects either of the triangles in the given
60  bool CellIntersect(int cx, int cz, const CVector3D& origin, const CVector3D& dir, float& dist) const;
61 
62  // The terrain we're operating on
64  // the heightfield were tracing
66  // size of the heightfield
67  size_t m_MapSize;
68  // cell size - size of each cell in x and z
69  float m_CellSize;
70  // vertical scale - size of each cell in y
72 };
73 
74 #endif
bool RayIntersect(const CVector3D &origin, const CVector3D &dir, int &x, int &z, CVector3D &ipt) const
Definition: HFTracer.cpp:133
uint16_t u16
Definition: types.h:38
Definition: HFTracer.h:31
static void out(const wchar_t *fmt,...)
Definition: wdbg_sym.cpp:421
float m_HeightScale
Definition: HFTracer.h:71
Definition: Vector3D.h:30
const u16 * m_Heightfield
Definition: HFTracer.h:65
Definition: Terrain.h:51
float m_CellSize
Definition: HFTracer.h:69
Definition: Patch.h:48
CTerrain * m_pTerrain
Definition: HFTracer.h:63
bool CellIntersect(int cx, int cz, const CVector3D &origin, const CVector3D &dir, float &dist) const
Definition: HFTracer.cpp:106
CHFTracer(CTerrain *pTerrain)
Definition: HFTracer.cpp:44
static bool PatchRayIntersect(CPatch *patch, const CVector3D &origin, const CVector3D &dir, CVector3D *out)
Intersects ray with a single patch.
Definition: HFTracer.cpp:275
size_t m_MapSize
Definition: HFTracer.h:67