2D Boxes

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Functions

Box2D	box2d (...)
Box2D	box2d_from_points (...)
V2D	box2d_center (...)
void	box2d_add (...)
void	box2d_addn (...)
void	box2d_add_circle (...)
void	box2d_merge (...)
void	box2d_segments (...)
real	box2d_area (...)
bool_t	box2d_is_null (...)

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Types and Constants

Box2D

kNULL

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2D containers or (Bounding boxes) delimit the area of the plane occupied by different geometric elements (Figure 1). They are useful in the collision detection or clipping operations, which prevent non-visible figures from being drawn, improving overall performance.

• Use box2d_from_pointsf to create a 2D box from a set of points.
• Use box2d_addnf to change dimensions based on new points.
• Use box2d_segmentsf to get the four segments that delimit the box.

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kNULL

const Box2Df kBOX2D_NULLf;

const Box2Dd kBOX2D_NULLd;

const Box2D Box2D::kNULL;

Represents a null box (without geometry).

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box2d ()

Create a new box with the indicated limits.

Box2Df
box2df(const real32_t minX,
       const real32_t minY,
       const real32_t maxX,
       const real32_t maxY);

Box2Dd
box2dd(const real64_t minX,
       const real64_t minY,
       const real64_t maxX,
       const real64_t maxY);

Box2D
Box2D(const real minX,
      const real minY,
      const real maxX,
      const real maxY);

minX	The lower limit on X.
minY	The lower limit on Y.
maxX	The upper limit on X.
maxY	The upper limit on Y.

Return

The newly created box.

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box2d_from_points ()

Create a new box containing a set of points.

Box2Df
box2d_from_pointsf(const V2Df *p,
                   const uint32_t n);

Box2Dd
box2d_from_pointsd(const V2Dd *p,
                   const uint32_t n);

Box2D
Box2D::from_points(const V2D *p,
                   const uint32_t n);

p	2d point vector.
n	Number of points in vector.

Return

The newly created box.

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box2d_center ()

Returns the center point.

V2Df
box2d_centerf(const Box2Df *box);

V2Dd
box2d_centerd(const Box2Dd *box);

V2D
Box2D::center(const Box2D *box);

box	The container.

Return

Center coordinates.

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box2d_add ()

Expand the dimensions of the box to contain the entry point. If the point is already within its area, the box is not modified.

void
box2d_addf(Box2Df *box,
           const V2Df *p);

void
box2d_addd(Box2Dd *box,
           const V2Dd *p);

void
Box2D::add(Box2D *box,
           const V2D *p);

box	The container.
p	The point to include.

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box2d_addn ()

Expand the dimensions of the box to contain several points. It is equivalent to calling the method box2d_addf successively.

void
box2d_addnf(Box2Df *box,
            const V2Df *p,
            const uint32_t n);

void
box2d_addnd(Box2Dd *box,
            const V2Dd *p,
            const uint32_t n);

void
Box2D::addn(Box2D *box,
            const V2D *p,
            const uint32_t n);

box	The container.
p	Vector points to include.
n	Number of points.

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box2d_add_circle ()

Expand the dimensions of the container to accommodate a circle.

void
box2d_add_circlef(Box2Df *box,
                  const Cir2Df *cir);

void
box2d_add_circled(Box2Dd *box,
                  const Cir2Dd *cir);

void
Box2D::add_circle(Box2D *box,
                  const Cir2D *cir);

box	The container.
cir	Circle.

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box2d_merge ()

Expand the dimensions of dest to contain src.

void
box2d_mergef(Box2Df *dest,
             const Box2Df *src);

void
box2d_merged(Box2Dd *dest,
             const Box2Dd *src);

void
Box2D::merge(Box2D *dest,
             const Box2D *src);

dest	The container that will be expanded.
src	The container that must be added.

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box2d_segments ()

Gets the four segments that make up the box.

void
box2d_segmentsf(const Box2Df *box,
                Seg2Df *segs);

void
box2d_segmentsd(const Box2Dd *box,
                Seg2Dd *segs);

void
Box2D::segments(const Box2D *box,
                Seg2D *segs);

box	The container.
segs	Array of at least four segments.

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box2d_area ()

Gets the area of ​​the box.

real32_t
box2d_areaf(const Box2Df *box);

real64_t
box2d_aread(const Box2Dd *box);

real
Box2D::area(const Box2D *box);

box	The container.

Return

The area (width * height).

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box2d_is_null ()

Check if a container is null (without any geometry inside).

bool_t
box2d_is_nullf(const Box2Df *box);

bool_t
box2d_is_nulld(const Box2Dd *box);

bool_t
Box2D::is_null(const Box2D *box);

box	The container.

Return

TRUE if is null, FALSE if contains any geometry.

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