asw::geometry Namespace Reference

Functions
template<typename T >
Vec2< T >::Real	signed_area (const Polygon< T > &polygon)
	Get the signed area of a polygon.
template<typename T >
Quad< T >	bounds (const Polygon< T > &polygon)
	Get the smallest rectangle that holds every corner of a polygon.
template<typename T >
bool	point_in_triangle (const Vec2< T > &point, const Vec2< T > &a, const Vec2< T > &b, const Vec2< T > &c)
	Check if a point is inside a triangle. Points on an edge are inside.
std::optional< float >	ray_hit (const Vec2f &origin, const Vec2f &direction, const Vec2f &a, const Vec2f &b)
	Find where a ray hits a line segment.
Polygonf	visibility (const Vec2f &from, float radius, const std::vector< Polygonf > &occluders, float direction=0.0F, float cone=0.0F)
	Find the area that can be seen from a point.
void	visibility (Polygonf &result, const Vec2f &from, float radius, const std::vector< Polygonf > &occluders, float direction=0.0F, float cone=0.0F)
	Find the area that can be seen from a point, into a polygon you keep between calls so it does not allocate each time.
void	visibility (Polygonf &result, const Vec2f &from, float radius, const std::vector< Polygonf > &occluders, const std::vector< Quadf > &occluder_bounds, float direction=0.0F, float cone=0.0F)
	Find the area that can be seen from a point, with the bounds of the occluders already worked out, e.g. once per frame for many lights.

Function Documentation

bounds()

template<typename T >

Quad< T > asw::geometry::bounds

(

const Polygon< T > &

polygon

)

Get the smallest rectangle that holds every corner of a polygon.

Parameters

polygon

The polygon.

Returns

The bounds, or an empty rectangle at 0, 0 for no corners.

Definition at line 766 of file geometry.h.

point_in_triangle()

template<typename T >

bool asw::geometry::point_in_triangle	(	const Vec2< T > &	point,
		const Vec2< T > &	a,
		const Vec2< T > &	b,
		const Vec2< T > &	c )

Check if a point is inside a triangle. Points on an edge are inside.

Parameters

point	The point to check.
a	The first corner.
b	The second corner.
c	The third corner.

Returns

true if the point is inside or on the edge.

Definition at line 790 of file geometry.h.

ray_hit()

std::optional< float > asw::geometry::ray_hit	(	const Vec2f &	origin,
		const Vec2f &	direction,
		const Vec2f &	a,
		const Vec2f &	b )

Find where a ray hits a line segment.

Parameters

origin	Where the ray starts.
direction	Which way the ray goes. It does not need to be normalized.
a	One end of the segment.
b	The other end of the segment.

Returns

How far along the ray the hit is, in lengths of direction, or nothing when the ray misses or runs along the segment.

Definition at line 86 of file geometry.cpp.

signed_area()

template<typename T >

Vec2< T >::Real asw::geometry::signed_area

(

const Polygon< T > &

polygon

)

Get the signed area of a polygon.

Parameters

polygon

The polygon.

Returns

The area. It is positive when the corners go clockwise on screen and negative when they go anticlockwise.

Definition at line 751 of file geometry.h.

visibility() [1/3]

asw::Polygonf asw::geometry::visibility	(	const Vec2f &	from,
		float	radius,
		const std::vector< Polygonf > &	occluders,
		float	direction = 0.0F,
		float	cone = 0.0F )

Find the area that can be seen from a point.

Useful for field of view and for light. Rays stop at the first polygon edge, and at a square of half size radius around from.

Parameters

from	The point to look from.
radius	How far to look.
occluders	Polygons that block the view.
direction	Direction to look, in radians, when cone is set.
cone	Width of the view in radians. 0 looks all round.

Returns

The edge of the visible area in angle order, not including from.

Definition at line 104 of file geometry.cpp.

visibility() [2/3]

void asw::geometry::visibility	(	Polygonf &	result,
		const Vec2f &	from,
		float	radius,
		const std::vector< Polygonf > &	occluders,
		const std::vector< Quadf > &	occluder_bounds,
		float	direction = 0.0F,
		float	cone = 0.0F )

Find the area that can be seen from a point, with the bounds of the occluders already worked out, e.g. once per frame for many lights.

Parameters

occluder_bounds

The bounds() of each occluder, in the same order. Must be the same size as occluders.

Definition at line 123 of file geometry.cpp.

visibility() [3/3]

void asw::geometry::visibility	(	Polygonf &	result,
		const Vec2f &	from,
		float	radius,
		const std::vector< Polygonf > &	occluders,
		float	direction = 0.0F,
		float	cone = 0.0F )

Find the area that can be seen from a point, into a polygon you keep between calls so it does not allocate each time.

Parameters

result

Replaced with the edge of the visible area.

Definition at line 112 of file geometry.cpp.