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/* Copyright (C) 2018 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_HELPER_GEOMETRY
#define INCLUDED_HELPER_GEOMETRY
/**
* @file
* Helper functions related to geometry algorithms
*/
#include "maths/Fixed.h"
#include "maths/FixedVector2D.h"
#include "maths/MathUtil.h"
namespace Geometry
{
/**
* Checks if a point is inside the given rotated rectangle.
* Points precisely on an edge are considered to be inside.
*
* The rectangle is defined by the four vertexes
* (+/-u*halfSize.X +/-v*halfSize.Y)
*
* The @p u and @p v vectors must be perpendicular.
*/
inline bool PointIsInSquare(const CFixedVector2D& point, const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize)
{
return point.Dot(u).Absolute() <= halfSize.X && point.Dot(v).Absolute() <= halfSize.Y;
}
/**
* Returns a vector (bx,by) such that every point inside
* the given rotated rectangle has coordinates
* (x,y) with -bx <= x <= bx, -by <= y < by.
*
* The rectangle is defined by the four vertexes
* (+/-u*halfSize.X +/-v*halfSize.Y).
*/
CFixedVector2D GetHalfBoundingBox(const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize);
/**
* Returns the minimum Euclidean distance from the given point to
* any point on the boundary of the given rotated rectangle.
*
* If @p countInsideAsZero is true, and the point is inside the rectangle,
* it will return 0.
* If @p countInsideAsZero is false, the (positive) distance to the boundary
* will be returned regardless of where the point is.
*
* The rectangle is defined by the four vertexes
* (+/-u*halfSize.X +/-v*halfSize.Y).
*
* The @p u and @p v vectors must be perpendicular and unit length.
*/
fixed DistanceToSquare(const CFixedVector2D& point,
const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize,
bool countInsideAsZero = false);
/**
* Similar to above but never uses sqrt, so it returns the squared distance.
*/
fixed DistanceToSquareSquared(const CFixedVector2D& point,
const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize,
bool countInsideAsZero = false);
/**
* Returns a point on the boundary of the given rotated rectangle
* that is closest (or equally closest) to the given point
* in Euclidean distance.
*
* The rectangle is defined by the four vertexes
* (+/-u*halfSize.X +/-v*halfSize.Y).
*
* The @p u and @p v vectors must be perpendicular and unit length.
*/
CFixedVector2D NearestPointOnSquare(const CFixedVector2D& point,
const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize);
bool TestRaySquare(const CFixedVector2D& a, const CFixedVector2D& b, const CFixedVector2D& u, const CFixedVector2D& v, const CFixedVector2D& halfSize);
bool TestRayAASquare(const CFixedVector2D& a, const CFixedVector2D& b, const CFixedVector2D& halfSize);
bool TestSquareSquare(
const CFixedVector2D& c0, const CFixedVector2D& u0, const CFixedVector2D& v0, const CFixedVector2D& halfSize0,
const CFixedVector2D& c1, const CFixedVector2D& u1, const CFixedVector2D& v1, const CFixedVector2D& halfSize1);
/**
* Used in Footprint when spawning units:
* Given a grid point (x, y) on the rectangle [-x_max, x_max] x [-y_max, y_max],
* this returns the distance travelled in moving from (x_max, 0) to the the point while
* walking counter-clockwise along the perimeter of the rectangle.
*/
int GetPerimeterDistance(int x_max, int y_max, int x, int y);
/**
* Used in Footprint when spawning units:
* This returns the grid point on the rectangle [-x_max, x_max] x [-y_max, y_max]
* reached after starting at (x_max, 0) and walking a distance k
* counter-clockwise along the perimeter of the rectangle.
*/
std::pair<int, int> GetPerimeterCoordinates(int x_max, int y_max, int k);
} // namespace
#endif // INCLUDED_HELPER_GEOMETRY
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