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/* Copyright (c) 1992 The Geometry Center; University of Minnesota
1300 South Second Street; Minneapolis, MN 55454, USA;
This file is part of geomview/OOGL. geomview/OOGL is free software;
you can redistribute it and/or modify it only under the terms given in
the file COPYING, which you should have received along with this file.
This and other related software may be obtained via anonymous ftp from
geom.umn.edu; email: software@geom.umn.edu. */
/* Authors: Charlie Gunn, Stuart Levy, Tamara Munzner, Mark Phillips */
/*
* iterate.c -- iteration over OOGL hierarchies
*/
#include <geomclass.h>
#include "listP.h"
#include "tlistP.h"
#include "instP.h"
#include "sphereP.h"
#include "discgrpP.h"
#define UNKNOWN 0
#define LIST 1
#define TLIST 2
#define INST 3
#define SPHERE 4
#define DISCGRP 5
#define OTHER 6
#define VALID 0x13ac2480 /* Magic number */
struct istate { /* Iteration state structure: per nest lvl */
struct istate *parent;
Geom *g;
int kind;
int seq; /* Seq number within Tlist */
Transform Ti;
};
struct GeomIter {
struct istate *stack;
int flags;
};
static struct GeomIter *itpool;
static struct istate *ispool;
#define NewIter(it) if(itpool) { it = itpool; itpool = NULL;} \
else it = (GeomIter *)malloc(sizeof(GeomIter))
#define NewIstate(is) if(ispool) { is = ispool; ispool = ispool->parent; } \
else is = (struct istate *)malloc(sizeof(struct istate))
#define FreeIter(it) if(itpool) GeomFree(it); else itpool = it
#define FreeIstate(is) (is)->parent = ispool, ispool = is
GeomIter *
GeomIterate(g, flags)
Geom *g;
int flags;
{
GeomIter *it;
register struct istate *is;
NewIter(it);
it->flags = (flags & 15) | VALID;
NewIstate(is);
it->stack = is;
is->kind = UNKNOWN;
is->g = g;
is->parent = NULL;
return it;
}
/*
* Iterate over an OOGL hierarchy, producing one Transform per call.
* Returns 1 normally, 0 when no more Transforms remain.
* Destroys the GeomIter upon returning 0.
*
* To make this work as a coroutine we effectively unroll the recursive
* hierarchy traversal, so please excuse the goto's.
*
* For speed, we act as a friend to the List, TList, Inst, and Sphere
* classes. XXX
*/
NextTransform(it, T)
GeomIter *it;
Transform T;
{
register struct istate *is;
Geom *g;
if(it == NULL)
return 0;
if((is = it->stack) == NULL)
goto gone;
g = is->g;
again:
switch(is->kind) {
case UNKNOWN: /* Determine type */
discover:
if(g->Class == TlistClass) {
if(g->magic != TLISTMAGIC) {
GeomError(0,"NextTransform: Surprise Tlist %x", g);
goto pop;
}
is->kind = TLIST;
is->seq = 0;
goto isTLIST;
}
if(g->Class == DiscGrpClass) {
if(g->magic != DISCGRPMAGIC) {
GeomError(0,"NextTransform: Surprise DiscGrp %x", g);
goto pop;
}
is->kind = DISCGRP;
is->seq = 0;
goto isDISCGRP;
}
if(g->Class == ListClass) {
if(g->magic != LISTMAGIC) {
GeomError(0,"NextTransform: Surprise List %x", g);
goto pop;
}
is->kind = LIST;
goto isLIST;
}
if(g->Class == InstClass || g->Class == SphereClass) {
register Inst *inst = (Inst *)g;
if(inst->magic != INSTMAGIC && inst->magic != SPHEREMAGIC) {
GeomError(0,"NextTransform: Surprise Inst %x", g);
goto pop;
}
if(inst->tlist == NULL) {
/*
* Just use this transform. We're a leaf, so return it now.
* Also pop stack for next iteration.
*/
if(is = is->parent)
TmConcat(inst->axis, is->Ti, T);
else
TmCopy(inst->axis, T);
FreeIstate(it->stack);
it->stack = is;
return 1;
} else {
/*
* Inst has a child.
* The axis field is *ignored* in this case; just
* traverse the child.
*/
is->g = g = inst->tlist;
/*is->kind = UNKNOWN;*/
goto discover;
}
}
/* Other objects aren't relevant for NextTransform(), so discard. */
goto pop;
case TLIST:
isTLIST:
{
register Tlist *TL = (Tlist *)g;
register float (*Tp)[4]; /* ought to be ``Transform *Tp'' */
if(is->seq >= TL->nelements)
goto pop;
Tp = TL->elements[is->seq++];
if(TL->tlist != NULL && !(it->flags & SHALLOW)) {
if(is->parent)
TmConcat(*Tp, is->parent->Ti, is->Ti);
else
TmCopy(*Tp, is->Ti);
g = TL->tlist;
goto push;
}
/* We're a leaf -- return a matrix now */
if(is->parent)
TmConcat(*Tp, is->parent->Ti, T);
else
TmCopy(*Tp, T);
return 1;
}
case DISCGRP:
isDISCGRP:
{
register DiscGrp *dg = (DiscGrp *)g;
register float (*Tp)[4]; /* ought to be ``Transform *Tp'' */
if(is->seq >= dg->big_list->num_el)
goto pop;
Tp = dg->big_list->el_list[is->seq++].tform;
/* if it's another discrete group ... */
if(dg->geom != NULL &&
dg->geom->magic == DISCGRPMAGIC && !(it->flags & SHALLOW)) {
if(is->parent)
TmConcat(*Tp, is->parent->Ti, is->Ti);
else
TmCopy(*Tp, is->Ti);
g = dg->geom;
goto push;
}
/* We're a leaf -- return a matrix now */
if(is->parent)
TmConcat(*Tp, is->parent->Ti, T);
else
TmCopy(*Tp, T);
return 1;
}
case LIST:
isLIST:
{
/* Might need some intra-List state too if List format
* gets fancier -- if we have one List object which contains a
* bundle of Geom's.
*/
register List *L = (List *)g;
if(L == NULL)
goto pop;
while(L->car == NULL) {
L = L->cdr;
if(L == NULL)
goto pop;
}
g = L->car;
is->g = (Geom *)L->cdr;
if(is->parent)
TmCopy(is->parent->Ti, is->Ti);
else
TmIdentity(is->Ti);
goto push;
}
default:
GeomError(1,"NextTransform: called with invalid GeomIter (%x)", it);
return 0;
}
push: /* Push g as a new element */
/* is->Ti *must* be set correctly before getting here! */
NewIstate(is);
is->g = g;
is->parent = it->stack;
it->stack = is;
goto discover; /* Recurse */
pop:
is = is->parent;
FreeIstate(it->stack);
it->stack = is;
if(is != NULL) {
g = is->g;
goto again; /* Recurse -- type already determined */
}
/* stack empty -- fall into gone: */
gone:
it->flags = 0;
it->stack = NULL;
FreeIter(it);
return 0;
}
void
DestroyIter(it)
GeomIter *it;
{
if((it->flags & 0xfffffff0) == VALID) {
it->flags = 0;
it->stack = NULL;
FreeIter(it);
} else {
GeomError(1,"DestroyIter -- already destroyed %x", it);
}
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.