The Segment Structure

Intersection segment. More...

Collaboration diagram for The Segment Structure:

Files
file	seg.h

Data Structures
struct	seg

Macros
#define	RT_SEG_NULL   ((struct seg *)0)
#define	RT_CHECK_SEG(_p)   BU_CKMAG(_p, RT_SEG_MAGIC, "struct seg")
#define	RT_CK_SEG(_p)   BU_CKMAG(_p, RT_SEG_MAGIC, "struct seg")
#define	RT_GET_SEG(p, res)
#define	RT_FREE_SEG(p, res)
#define	RT_FREE_SEG_LIST(_segheadp, _res)

Functions
void	rt_pr_seg (const struct seg *segp)
void	rt_pr_seg_vls (struct bu_vls *, const struct seg *)

Detailed Description

Intersection segment.

A "seg" or segment is a low level in/out ray/shape intersection solution, derived by performing intersection calculations between a ray and a single object. Depending on the type of shape, a single ray may produce multiple segments when intersected with that shape. Unless the object happens to also be a top-level unioned object in the database, individual segments must be "woven" together using boolean hierarchies to obtain the final partitions which describe solid geometry along a ray. An individual segment may have either a positive or negative contribution to the "final" partition, depending on whether parent combs designate their children as unioned, intersected, or subtracted.

Macro Definition Documentation

RT_SEG_NULL

#define RT_SEG_NULL   ((struct seg *)0)

Definition at line 65 of file seg.h.

RT_CHECK_SEG

#define RT_CHECK_SEG

(

_p

)

BU_CKMAG(_p, RT_SEG_MAGIC, "struct seg")

Definition at line 67 of file seg.h.

RT_CK_SEG

#define RT_CK_SEG

(

_p

)

BU_CKMAG(_p, RT_SEG_MAGIC, "struct seg")

Definition at line 68 of file seg.h.

RT_GET_SEG

#define RT_GET_SEG	(		p,
			res
	)

Value:

        { \
        while (!BU_LIST_WHILE((p), seg, &((res)->re_seg)) || !(p)) \
            rt_alloc_seg_block(res); \
        BU_LIST_DEQUEUE(&((p)->l)); \
        (p)->l.forw = (p)->l.back = BU_LIST_NULL; \
        (p)->seg_in.hit_magic = (p)->seg_out.hit_magic = RT_HIT_MAGIC; \
        res->re_segget++; \
    }

Definition at line 70 of file seg.h.

RT_FREE_SEG

#define RT_FREE_SEG	(		p,
			res
	)

Value:

        { \
        RT_CHECK_SEG(p); \
        BU_LIST_INSERT(&((res)->re_seg), &((p)->l)); \
        res->re_segfree++; \
    }

Definition at line 80 of file seg.h.

RT_FREE_SEG_LIST

#define RT_FREE_SEG_LIST	(		_segheadp,
			_res
	)

Value:

        { \
        register struct seg *_a; \
        while (BU_LIST_WHILE(_a, seg, &((_segheadp)->l))) { \
            BU_LIST_DEQUEUE(&(_a->l)); \
            RT_FREE_SEG(_a, _res); \
        } \
    }

This could be BU_LIST_INSERT_LIST(&((_res)->re_seg), &((_segheadp)->l)) except for security of checking & counting each element this way.

Definition at line 92 of file seg.h.

Function Documentation

rt_pr_seg()

void rt_pr_seg

(

const struct seg *

segp

)

rt_pr_seg_vls()

void rt_pr_seg_vls	(	struct bu_vls *	,
		const struct seg *
	)