r2d.h File Reference

#include <stdint.h>

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Classes
struct	r2d_rvec2
	Vector struct. More...
struct	r2d_dvec2
	Integer vector struct for grid indexing. More...
struct	r2d_plane
	A plane. More...
struct	r2d_orientation
	Perpendicular distances and bit flags for up to 6 faces. More...
struct	r2d_vertex
	A doubly-linked vertex. More...
struct	r2d_poly
	A polygon. More...
struct	r2d_dest_grid
	Destination grid information. More...

Macros
#define	R2D_MAX_VERTS   64

Typedefs
typedef double	r2d_real
	Real type specifying the precision to be used in calculations. More...
typedef int32_t	r2d_int
	Integer type used for grid indexing and bit flags. More...
typedef int64_t	r2d_long
	Long integer type used for grid indexing. More...

Functions
void	r2d_rasterize_quad (r2d_plane *faces, r2d_dest_grid *grid)
	Rasterize a convex quadrilateral to the destination grid. More...
void	r2d_clip_quad (r2d_poly *poly, unsigned char andcmp)
	Clip a polygon against four clip planes (find its intersection with a quadrilateral). More...
void	r2d_reduce (r2d_poly *poly, r2d_int polyorder, r2d_real *moments)
	Integrate a polynomial density over a polygon using simplicial decomposition. More...
void	r2du_init_box (r2d_poly *poly, r2d_rvec2 rbounds[2])
	Initialize a polygon as an axis-aligned box. More...
void	r2du_faces_from_verts (r2d_rvec2 *verts, r2d_int nverts, r2d_plane *faces)
	Get faces (unit normals and distances to the origin) from an ordered-vertex description of a convex polygon. More...
r2d_real	r2du_orient (r2d_rvec2 pa, r2d_rvec2 pb, r2d_rvec2 pc)
	Get the signed area of the triangle defined by the input vertices. More...

Macro Definition Documentation

R2D_MAX_VERTS

#define R2D_MAX_VERTS   64

Typedef Documentation

r2d_int

typedef int32_t r2d_int

Integer type used for grid indexing and bit flags.

r2d_long

typedef int64_t r2d_long

Long integer type used for grid indexing.

r2d_real

typedef double r2d_real

Real type specifying the precision to be used in calculations.

Default is double (recommended). float precision is enabled by compiling with -DSINGLE_PRECISION.

Function Documentation

r2d_clip_quad()

void r2d_clip_quad	(	r2d_poly *	poly,
		unsigned char	andcmp
	)

Clip a polygon against four clip planes (find its intersection with a quadrilateral).

Parameters

[in,out]	poly	The polygon to be clipped. The distances to the clip plane and bit flags in poly.verts[...].orient must be set prior to calling this function.
[in]	andcmp	Set of bit flags allowing faces to be skipped. Face f will be skipped if andcmp & (1 << f) evaluates to true.

r2d_rasterize_quad()

void r2d_rasterize_quad	(	r2d_plane *	faces,
		r2d_dest_grid *	grid
	)

Rasterize a convex quadrilateral to the destination grid.

Parameters

[in]	faces	The four faces of the quadrilateral to be voxelized.
[in,out]	grid	The destination grid buffer that the quadrilateral will be voxelized to. The results of the rasterization are found in grid.moments.

r2d_reduce()

void r2d_reduce	(	r2d_poly *	poly,
		r2d_int	polyorder,
		r2d_real *	moments
	)

Integrate a polynomial density over a polygon using simplicial decomposition.

Parameters

[in]	poly	The polygon over which to integrate.
[in]	polyorder	Order of the polynomial density field. 0 for constant (1 moment), 1 for linear (3 moments), 2 for quadratic (6 moments).
[in,out]	moments	Array to be filled with the integration results, up to the sepcified polyorder. Order of moments is 1, x, y, x^2, y^2, x*y.

r2du_faces_from_verts()

void r2du_faces_from_verts	(	r2d_rvec2 *	verts,
		r2d_int	nverts,
		r2d_plane *	faces
	)

Get faces (unit normals and distances to the origin) from an ordered-vertex description of a convex polygon.

Parameters

[in]	verts	List of polygon vertices.
[in]	nverts	Number of polygon vertices in the list.
[out]	faces	Array of planes defining the faces of the polygon. Must be at least nverts in size.

r2du_init_box()

void r2du_init_box	(	r2d_poly *	poly,
		r2d_rvec2	rbounds[2]
	)

Initialize a polygon as an axis-aligned box.

Parameters

[in,out]	poly	The polygon to initialize.
[in]	rbounds	An array of two vectors, giving the lower and upper corners of the box.

r2du_orient()

r2d_real r2du_orient	(	r2d_rvec2	pa,
		r2d_rvec2	pb,
		r2d_rvec2	pc
	)

Get the signed area of the triangle defined by the input vertices.

Parameters

[in]

pa,pb,pc

Vertices defining a triangle from which to calculate an area.

Returns

The signed area of the input triangle.