91 lines
4.4 KiB
C++
91 lines
4.4 KiB
C++
/* Copyright (C) 2012 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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#ifndef INCLUDED_HELPER_GEOMETRY
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#define INCLUDED_HELPER_GEOMETRY
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/**
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* @file
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* Helper functions related to geometry algorithms
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*/
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#include "maths/Fixed.h"
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#include "maths/MathUtil.h"
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class CFixedVector2D;
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namespace Geometry
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{
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/**
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* Checks if a point is inside the given rotated square or rectangle.
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*
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* @note Currently assumes the @p u and @p v vectors are perpendicular.
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* @param point point vector of the point that is to be tested relative to the origin (center) of the shape.
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* @param u rotated X axis unit vector relative to the absolute XZ plane. Indicates the orientation of the rectangle. If not rotated,
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* this value is the absolute X axis unit vector (1,0). If rotated by angle theta, this should be (cos theta, -sin theta), as
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* the absolute Z axis points down in the unit circle.
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* @param v rotated Z axis unit vector relative to the absolute XZ plane. Indicates the orientation of the rectangle. If not rotated,
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* this value is the absolute Z axis unit vector (0,1). If rotated by angle theta, this should be (sin theta, cos theta), as
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* the absolute Z axis points down in the unit circle.
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* @param halfSize Holds half the dimensions of the shape along the u and v vectors, respectively.
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*
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* @return true if @p point is inside the square with rotated X axis unit vector @p u and rotated Z axis unit vector @p v,
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* and half dimensions specified by @p halfSizes.
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*/
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bool PointIsInSquare(CFixedVector2D point, CFixedVector2D u, CFixedVector2D v, CFixedVector2D halfSize);
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CFixedVector2D GetHalfBoundingBox(CFixedVector2D u, CFixedVector2D v, CFixedVector2D halfSize);
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fixed DistanceToSquare(CFixedVector2D point, CFixedVector2D u, CFixedVector2D v, CFixedVector2D halfSize);
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/**
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* Given a circle of radius @p radius, and a chord of length @p chordLength on this circle, computes the central angle formed by
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* connecting the chord's endpoints to the center of the circle.
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*
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* @param radius Radius of the circle; must be strictly positive.
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*/
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float ChordToCentralAngle(const float chordLength, const float radius);
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/**
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* Find point closest to the given point on the edge of the given square or rectangle.
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*
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* @note Currently assumes the @p u and @p v vectors are perpendicular.
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* @param point point vector of the point we want to get the nearest edge point for, relative to the origin (center) of the shape.
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* @param u rotated X axis unit vector, relative to the absolute XZ plane. Indicates the orientation of the shape. If not rotated,
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* this value is the absolute X axis unit vector (1,0). If rotated by angle theta, this should be (cos theta, -sin theta).
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* @param v rotated Z axis unit vector, relative to the absolute XZ plane. Indicates the orientation of the shape. If not rotated,
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* this value is the absolute Z axis unit vector (0,1). If rotated by angle theta, this should be (sin theta, cos theta).
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* @param halfSize Holds half the dimensions of the shape along the u and v vectors, respectively.
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*
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* @return point that is closest to @p point on the edge of the square specified by orientation unit vectors @p u and @p v and half
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* dimensions @p halfSize, relative to the center of the square
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*/
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CFixedVector2D NearestPointOnSquare(CFixedVector2D point, CFixedVector2D u, CFixedVector2D v, CFixedVector2D halfSize);
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bool TestRaySquare(CFixedVector2D a, CFixedVector2D b, CFixedVector2D u, CFixedVector2D v, CFixedVector2D halfSize);
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bool TestRayAASquare(CFixedVector2D a, CFixedVector2D b, CFixedVector2D halfSize);
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bool TestSquareSquare(
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CFixedVector2D c0, CFixedVector2D u0, CFixedVector2D v0, CFixedVector2D halfSize0,
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CFixedVector2D c1, CFixedVector2D u1, CFixedVector2D v1, CFixedVector2D halfSize1);
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} // namespace
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#endif // INCLUDED_HELPER_GEOMETRY
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