Ykkrosh
eb7955599a
Do some intersection tests on the CPU so that the silhouette render passes only have to draw models/patches that might actually contribute to silhouettes, saving the CPU and GPU cost of rendering more objects than necessary. This was SVN commit r15483.
75 lines
2.7 KiB
C++
75 lines
2.7 KiB
C++
/* Copyright (C) 2014 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Determine intersection of rays with a heightfield.
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*/
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#ifndef INCLUDED_HFTRACER
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#define INCLUDED_HFTRACER
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class CPatch;
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class CVector3D;
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class CTerrain;
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///////////////////////////////////////////////////////////////////////////////
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// CHFTracer: a class for determining ray intersections with a heightfield
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class CHFTracer
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{
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public:
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// constructor; setup data
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CHFTracer(CTerrain *pTerrain);
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// intersect ray with this heightfield; return true if intersection
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// occurs (and fill in grid coordinates and point of intersection), or false otherwise
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bool RayIntersect(const CVector3D& origin, const CVector3D& dir, int& x, int& z, CVector3D& ipt) const;
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/**
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* Intersects ray with a single patch.
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* The ray is a half-infinite line starting at @p origin with direction @p dir
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* (not required to be a unit vector).. The patch is treated as a collection
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* of two-sided triangles, corresponding to the terrain tiles.
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*
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* If there is an intersection, returns true; and if @p out is not NULL, it
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* is set to the intersection point. This is guaranteed to be the earliest
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* tile intersected (starting at @p origin), but not necessarily the earlier
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* triangle inside that tile.
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*
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* This partly duplicates RayIntersect, but it only operates on a single
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* patch, and it's more precise (it uses the same tile triangulation as the
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* renderer), and tries to be more numerically robust.
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*/
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static bool PatchRayIntersect(CPatch* patch, const CVector3D& origin, const CVector3D& dir, CVector3D* out);
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private:
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// test if ray intersects either of the triangles in the given
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bool CellIntersect(int cx, int cz, const CVector3D& origin, const CVector3D& dir, float& dist) const;
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// The terrain we're operating on
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CTerrain *m_pTerrain;
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// the heightfield were tracing
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const u16* m_Heightfield;
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// size of the heightfield
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size_t m_MapSize;
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// cell size - size of each cell in x and z
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float m_CellSize;
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// vertical scale - size of each cell in y
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float m_HeightScale;
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};
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#endif
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