circle.hpp

/*
	Copyright (c) 2022 Daniel Valcour
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	this software and associated documentation files (the "Software"), to deal in
	the Software without restriction, including without limitation the rights to
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	the Software, and to permit persons to whom the Software is furnished to do so,
	subject to the following conditions:
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	copies or substantial portions of the Software.
	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
	FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
	COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
	IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef RLFW_MATH_GRID_CIRCLE2_HPP
#define RLFW_MATH_GRID_CIRCLE2_HPP

#include <rlfw/math/common/concepts.hpp>
#include <rlfw/math/grid/circle2_def.hpp>
#include <rlfw/math/grid/point2.hpp>
#include <rlfw/math/grid/segment2.hpp>
#include <rlfw/math/grid/rect2.hpp>
#include <rlfw/math/grid/distance.hpp>
#include <rlfw/math/common/round.hpp>

#include <optional>
		
template<rl::signed_integral I, rl::floating_point F>
constexpr rl::circle2<I, F>::circle2(const I center_x, const I center_y, const F radius) noexcept
	: center_x(center_x)
	, center_y(center_y)
	, radius(radius)
{}

template<rl::signed_integral I, rl::floating_point F>
constexpr rl::point2<I> rl::circle2<I, F>::center() const noexcept
{
	return rl::point2<I>(this->center_x, this->center_y);
}

template<rl::signed_integral I, rl::floating_point F>
constexpr I rl::circle2<I, F>::left_x() const noexcept
{
	return static_cast<I>(static_cast<F>(this->center_x) - rl::round(this->radius));
}

template<rl::signed_integral I, rl::floating_point F>
constexpr I rl::circle2<I, F>::right_x() const noexcept
{
	return static_cast<I>(static_cast<F>(this->center_x) + rl::round(this->radius));
}

template<rl::signed_integral I, rl::floating_point F>
constexpr I rl::circle2<I, F>::top_y() const noexcept
{
	return static_cast<I>(static_cast<F>(this->center_y) - rl::round(this->radius));
}

template<rl::signed_integral I, rl::floating_point F>
constexpr I rl::circle2<I, F>::bottom_y() const noexcept
{
	return static_cast<I>(static_cast<F>(this->center_y) + rl::round(this->radius));
}

template<rl::signed_integral I, rl::floating_point F>
constexpr rl::point2<I> rl::circle2<I, F>::left() const noexcept
{
	return rl::point2<I>(this->left_x(), this->center_y);
}

template<rl::signed_integral I, rl::floating_point F>
constexpr rl::point2<I> rl::circle2<I, F>::right() const noexcept
{
	return rl::point2<I>(this->right_x(), this->center_y);
}

template<rl::signed_integral I, rl::floating_point F>
constexpr rl::point2<I> rl::circle2<I, F>::top() const noexcept
{
	return rl::point2<I>(this->center_x, this->top_y());
}

template<rl::signed_integral I, rl::floating_point F>
constexpr rl::point2<I> rl::circle2<I, F>::bottom() const noexcept
{
	return rl::point2<I>(this->center_x, this->bottom_y());
}

template<rl::signed_integral I, rl::floating_point F>
constexpr I rl::circle2<I, F>::dimensions() const noexcept
{
	return static_cast<I>(rl::round(this->diameter()));
}

template<rl::signed_integral I, rl::floating_point F>
constexpr F rl::circle2<I, F>::diameter() const noexcept
{
	return this->radius * static_cast<F>(2);
}

template<rl::signed_integral I, rl::floating_point F>
constexpr std::optional<rl::rect2<I>> rl::circle2<I, F>::bounds() const noexcept
{
	if (this->is_degenerate()) return std::nullopt;
	return rl::rect2<I>(this->left_x(), this->top_y(), this->dimensions(), this->dimensions());
}

template<rl::signed_integral I, rl::floating_point F>
constexpr bool rl::circle2<I, F>::is_degenerate() const noexcept
{
	return this->radius < static_cast<F>(0.5);
}

template<rl::signed_integral I, rl::floating_point F>
constexpr bool rl::circle2<I, F>::contains(const rl::point2<I>& other) const noexcept
{
	return 
		!this->is_degenerate() &&
		rl::distance<F>(this->center(), other) < this->radius;
}

template<rl::signed_integral I, rl::floating_point F>
constexpr bool rl::circle2<I, F>::contains(const rl::segment2<I>& other) const noexcept
{
	return
		!this->is_degenerate() &&
		rl::distance<F>(this->center(), other.start()) <= this->radius &&
		rl::distance<F>(this->center(), other.end()) <= this->radius;
}

template<rl::signed_integral I, rl::floating_point F>
constexpr bool rl::circle2<I, F>::contains(const rl::rect2<I>& other) const noexcept
{
	return
		!this->is_degenerate() &&
		!other.is_degenerate() &&
		rl::distance<F>(this->center(), other.top_left()) <= this->radius &&
		rl::distance<F>(this->center(), other.top_right()) <= this->radius &&
		rl::distance<F>(this->center(), other.bottom_left()) <= this->radius &&
		rl::distance<F>(this->center(), other.bottom_right()) <= this->radius;
}

template<rl::signed_integral I, rl::floating_point F>
constexpr bool rl::circle2<I, F>::contains(const rl::circle2<I, F>& other) const noexcept
{
	return
		!this->is_degenerate() &&
		!other.is_degenerate() &&
		rl::distance<F>(this->center(), other.left()) <= this->radius &&
		rl::distance<F>(this->center(), other.right()) <= this->radius &&
		rl::distance<F>(this->center(), other.top()) <= this->radius &&
		rl::distance<F>(this->center(), other.bottom()) <= this->radius;
}

#endif