gvrender_gd_vrml.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
 
#include "config.h"
#include "gdgen_text.h"
#include <assert.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdatomic.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <fcntl.h>
 
#include <gvc/gvplugin_render.h>
#include <gvc/gvio.h>
#include <gd.h>
 
#ifdef HAVE_GD_PNG
 
/* for gvcolor_t */
#include <common/color.h>
 
#include <cgraph/cgraph.h>
#include <common/render.h>
#include <util/agxbuf.h>
#include <util/alloc.h>
#include <util/gv_math.h>
#include <util/overflow.h>
#include <util/strview.h>
#include <util/unreachable.h>
 
/* for wind() */
#include <pathplan/pathutil.h>
 
enum { FORMAT_VRML, };
 
#define BEZIERSUBDIVISION 10
 
typedef struct {
  double Scale;
  double MinZ;
  bool Saw_skycolor;
 
  gdImagePtr im;
  FILE *PNGfile;
  int    IsSegment;   /* set true if edge is line segment */
  double CylHt;       /* height of cylinder part of edge */
  double EdgeLen;     /* length between centers of endpoints */
  double HeadHt, TailHt;  /* height of arrows */
  double Fstz, Sndz;  /* z values of tail and head points */
} state_t;
 
static void vrml_begin_job(GVJ_t *job) {
  job->context = gv_alloc(sizeof(state_t));
}
 
static void vrml_end_job(GVJ_t *job) {
  free(job->context);
}
 
/* Returns directory pathname prefix
 * Code adapted from dgk
 */
static strview_t gdirname(const char *pathname){
    /* go to end of path */
    size_t last = strlen(pathname);
    /* back over trailing '/' */
    while (last > 0 && pathname[--last] == '/');
    /* back over non-slash chars */
    for (; last > 0 && pathname[last] != '/'; last--);
    if (last == 0) {
        /* all '/' or "" */
        if (*pathname != '/')
            return strview(".", '\0');
        /* preserve // */
        else if (pathname[1] == '/')
            last++;
    } else {
        /* back over trailing '/' */
        for (; pathname[last] == '/' && last > 0; last--);
        /* preserve // */
        if (last == 0 && *pathname == '/' && pathname[1] == '/')
            last++;
    }
    last++;
 
    return (strview_t){.data = pathname, .size = last};
}
 
static char *nodefilename(const char *filename, node_t *n, agxbuf *buf) {
    strview_t dir;
 
    if (filename)
        dir = gdirname(filename);
    else
        dir = strview(".", '\0');
    agxbprint(buf, "%.*s/node%d.png", (int)dir.size, dir.data, AGSEQ(n));
    return agxbuse(buf);
}
 
static FILE *nodefile(const char *filename, node_t * n)
{
    FILE *rv;
    agxbuf buf = {0};
 
    rv = fopen(nodefilename(filename, n, &buf), "wb");
    agxbfree(&buf);
    return rv;
}
 
#define NODE_PAD 1
 
static pointf vrml_node_point(GVJ_t *job, node_t *n, pointf p)
{
    pointf rv;
    state_t *state = job->context;
 
    /* make rv relative to PNG canvas */
    if (job->rotation) {
        rv.x = ( (p.y - job->pad.y) - ND_coord(n).y + ND_lw(n)     ) * state->Scale + NODE_PAD;
        rv.y = (-(p.x - job->pad.x) + ND_coord(n).x + ND_ht(n) / 2.) * state->Scale + NODE_PAD;
    } else {
        rv.x = ( (p.x - job->pad.x) - ND_coord(n).x + ND_lw(n)     ) * state->Scale + NODE_PAD;
        rv.y = (-(p.y - job->pad.y) + ND_coord(n).y + ND_ht(n) / 2.) * state->Scale + NODE_PAD;
    }
    return rv;
}
 
static int color_index(gdImagePtr im, gvcolor_t color)
{
    int alpha;
 
    /* convert alpha (normally an "opacity" value) to gd's "transparency" */
    alpha = (255 - color.u.rgba[3]) * gdAlphaMax / 255;
 
    if(alpha == gdAlphaMax)
        return gdImageGetTransparent(im);
    else
        return gdImageColorResolveAlpha(im,
                    color.u.rgba[0],
                    color.u.rgba[1],
                    color.u.rgba[2],
                    alpha);
}
 
static int set_penstyle(GVJ_t *job, gdImagePtr im) {
    obj_state_t *obj = job->obj;
    int i, pen, pencolor, transparent, dashstyle[20];
 
    pen = pencolor = color_index(im, obj->pencolor);
    transparent = gdImageGetTransparent(im);
    if (obj->pen == PEN_DASHED) {
        for (i = 0; i < 10; i++)
            dashstyle[i] = pencolor;
        for (; i < 20; i++)
            dashstyle[i] = transparent;
        gdImageSetStyle(im, dashstyle, 20);
        pen = gdStyled;
    } else if (obj->pen == PEN_DOTTED) {
        for (i = 0; i < 2; i++)
            dashstyle[i] = pencolor;
        for (; i < 12; i++)
            dashstyle[i] = transparent;
        gdImageSetStyle(im, dashstyle, 12);
        pen = gdStyled;
    }
    int width = d2i(obj->penwidth * job->scale.x);
    if (width < PENWIDTH_NORMAL)
        width = PENWIDTH_NORMAL;  /* gd can't do thin lines */
    gdImageSetThickness(im, width);
    /* use brush instead of Thickness to improve end butts */
    if (width != (int)PENWIDTH_NORMAL) {
        gdImagePtr const brush = gdImageCreate(width, width);
        gdImagePaletteCopy(brush, im);
        gdImageFilledRectangle(brush, 0, 0, width - 1, width - 1, pencolor);
        gdImageSetBrush(im, brush);
        if (pen == gdStyled)
            pen = gdStyledBrushed;
        else
            pen = gdBrushed;
        gdImageDestroy(brush);
    }
    return pen;
}
 
/* warmed over VRML code starts here */
 
static void vrml_begin_page(GVJ_t *job)
{
    state_t *state = job->context;
    state->Scale = (double) DEFAULT_DPI / POINTS_PER_INCH;
    gvputs(job,   "#VRML V2.0 utf8\n");
 
    state->Saw_skycolor = false;
    state->MinZ = DBL_MAX;
    gvputs(job,   "Group { children [\n"
                  "  Transform {\n");
    gvprintf(job, "    scale %.3f %.3f %.3f\n", .0278, .0278, .0278);
    gvputs(job,   "    children [\n");
}
 
static void vrml_end_page(GVJ_t *job)
{
    double d, z;
    box bb = job->boundingBox;
    state_t *state = job->context;
 
    d = MAX(bb.UR.x - bb.LL.x,bb.UR.y - bb.LL.y);
    /* Roughly fill 3/4 view assuming FOV angle of M_PI/4.
     * Small graphs and non-square aspect ratios will upset this.
     */
    z = 0.6667 * d / tan(M_PI / 8.0) + state->MinZ; // fill ¾ of view
 
    if (!state->Saw_skycolor)
        gvputs(job,   " Background { skyColor 1 1 1 }\n");
    gvputs(job,   "  ] }\n");
    gvprintf(job, "  Viewpoint {position %.3f %.3f %.3f}\n",
            state->Scale * (bb.UR.x + bb.LL.x) / 72.,
            state->Scale * (bb.UR.y + bb.LL.y) / 72.,
            state->Scale * 2 * z / 72.);
    gvputs(job,   "] }\n");
}
 
static void vrml_begin_node(GVJ_t *job)
{
    obj_state_t *obj = job->obj;
    node_t *n = obj->u.n;
    double z = obj->z;
    int transparent;
    state_t *state = job->context;
 
    gvprintf(job, "# node %s\n", agnameof(n));
    if (z < state->MinZ)
        state->MinZ = z;
    if (shapeOf(n) != SH_POINT) {
        state->PNGfile = nodefile(job->output_filename, n);
        if (state->PNGfile == NULL) {
                agerrorf("failed to open file for writing PNG node image\n");
        }
 
        const int width  = d2i((ND_lw(n) + ND_rw(n)) * state->Scale + 2 * NODE_PAD);
        const int height = d2i((ND_ht(n)           ) * state->Scale + 2 * NODE_PAD);
        state->im = gdImageCreate(width, height);
 
        /* make background transparent */
        transparent = gdImageColorResolveAlpha(state->im,
                                           gdRedMax - 1, gdGreenMax,
                                           gdBlueMax, gdAlphaTransparent);
        gdImageColorTransparent(state->im, transparent);
    }
}
 
static void vrml_end_node(GVJ_t *job)
{
    state_t *state = job->context;
    if (state->im) {
        if (state->PNGfile != NULL) {
                gdImagePng(state->im, state->PNGfile);
                fclose(state->PNGfile);
        }
        gdImageDestroy(state->im);
        state->im = NULL;
    }
}
 
static void vrml_begin_edge(GVJ_t *job)
{
    obj_state_t *obj = job->obj;
    edge_t *e = obj->u.e;
    state_t *state = job->context;
 
    state->IsSegment = 0;
    gvprintf(job, "# edge %s -> %s\n", agnameof(agtail(e)), agnameof(aghead(e)));
    gvputs(job,   " Group { children [\n");
}
 
static void
finishSegment (GVJ_t *job, edge_t *e)
{
    pointf p0 = gvrender_ptf(job, ND_coord(agtail(e)));
    pointf p1 = gvrender_ptf(job, ND_coord(aghead(e)));
    double x, y, z;
    state_t *state = job->context;
 
    const double o_x = (p0.x + p1.x) / 2.0;
    const double o_y = (p0.y + p1.y) / 2.0;
    const double o_z = (state->Fstz + state->Sndz) / 2;
    /* Compute rotation */
    /* Pick end point with highest y */
    if (p0.y > p1.y) {
        x = p0.x;
        y = p0.y;
        z = state->Fstz;
    }
    else {
        x = p1.x;
        y = p1.y;
        z = state->Sndz;
    }
    /* Translate center to the origin */
    x -= o_x;
    y -= o_y;
    z -= o_z;
    const double theta =
      acos(2 * y / state->EdgeLen) + (p0.y > p1.y ? M_PI : 0);
    if (fabs(x) < 0.0005 && fabs(z) < 0.0005) // parallel to y-axis
        x = 1;
 
    const double y0 = (state->HeadHt - state->TailHt) / 2.0;
    gvputs(job,   "      ]\n");
    gvprintf(job, "      center 0 %.3f 0\n", y0);
    gvprintf(job, "      rotation %.3f 0 %.3f %.3f\n", -z, x, -theta);
    gvprintf(job, "      translation %.3f %.3f %.3f\n", o_x, o_y - y0, o_z);
    gvputs(job,   "    }\n");
}
 
static void vrml_end_edge(GVJ_t *job)
{
    state_t *state = job->context;
 
    if (state->IsSegment)
        finishSegment(job, job->obj->u.e);
    gvputs(job,   "] }\n");
}
 
static void vrml_textspan(GVJ_t *job, pointf p, textspan_t * span)
{
    obj_state_t *obj = job->obj;
    pointf spf, epf, q;
    state_t *state = job->context;
 
    if (!obj->u.n || !state->im)   /* if not a node - or if no im (e.g. for cluster) */
        return;
 
    switch (span->just) {
    case 'l':
        break;
    case 'r':
        p.x -= span->size.x;
        break;
    default:
    case 'n':
        p.x -= span->size.x / 2;
        break;
    }
    q.x = p.x + span->size.x;
    q.y = p.y;
 
    spf = vrml_node_point(job, obj->u.n, p);
    epf = vrml_node_point(job, obj->u.n, q);
 
    gdgen_text(state->im, spf, epf,
        color_index(state->im, obj->pencolor),
        span->font->size,
        DEFAULT_DPI,
        job->rotation ? M_PI / 2 : 0,
        span->font->name,
        span->str);
}
 
/* Given 2 points in 3D p = (fst.x,fst.y,fstz) and q = (snd.x, snd.y, sndz),
 * and a point p1 in the xy plane lying on the line segment connecting 
 * the projections of the p and q, find the z coordinate of p1 when it
 * is projected up onto the segment (p,q) in 3-space. 
 *
 * Why the special case for ranks? Is the arithmetic really correct?
 */
static double 
interpolate_zcoord(GVJ_t *job, pointf p1, pointf fst, double fstz, pointf snd, double sndz)
{
    obj_state_t *obj = job->obj;
    edge_t *e = obj->u.e;
 
    if (ND_rank(agtail(e)) != ND_rank(aghead(e))) {
        double res;
        if (fdiv_overflow(fstz + (sndz - fstz) * (p1.y - fst.y), snd.y - fst.y, &res))
            return (fstz + sndz) / 2.0;
        return res;
    } 
    const double len = DIST(fst, snd);
    const double d = DIST(p1, fst) / len;
    return fstz + d * (sndz - fstz);
}
 
static int
collinear (pointf * A)
{
    const double w = wind(A[0],A[1],A[2]);
    return fabs(w) <= 1;
}
 
/* Return true if Bézier points are collinear
 * At present, just check with 4 points, the common case.
 */
static int straight(pointf *A, size_t n) {
    if (n != 4) return 0;
    return collinear(A) && collinear(A + 1);
}
 
static void
doSegment (GVJ_t *job, pointf* A, pointf p0, double z0, pointf p1, double z1)
{
    obj_state_t *obj = job->obj;
    double d1, d0;
    double delx, dely, delz;
    state_t *state = job->context;
 
    delx = p0.x - p1.x;
    dely = p0.y - p1.y;
    delz = z0 - z1;
    state->EdgeLen = sqrt(delx*delx + dely*dely + delz*delz);
    d0 = DIST(A[0],p0);
    d1 = DIST(A[3],p1);
    state->CylHt = state->EdgeLen - d0 - d1;
    state->TailHt = state->HeadHt = 0;
 
    state->IsSegment = 1;
    gvputs(job,   "Transform {\n"
                  "  children [\n"
                  "    Shape {\n"
                  "      geometry Cylinder {\n"
                  "        bottom FALSE top FALSE\n");
    gvprintf(job, "        height %.3f radius %.3f }\n", state->CylHt, obj->penwidth);
    gvputs(job,   "      appearance Appearance {\n"
                  "        material Material {\n"
                  "          ambientIntensity 0.33\n");
    gvprintf(job, "          diffuseColor %.3f %.3f %.3f\n",
            obj->pencolor.u.rgba[0] / 255.,
            obj->pencolor.u.rgba[1] / 255.,
            obj->pencolor.u.rgba[2] / 255.);
    gvputs(job,   "        }\n"
                  "      }\n"
                  "    }\n");
}
 
/* Given a point a and edge e, return true if a is closer to the
 * tail of e than the head.
 */
static int
nearTail (GVJ_t* job, pointf a, Agedge_t* e)
{
    pointf tp = gvrender_ptf(job, ND_coord(agtail(e)));
    pointf hp = gvrender_ptf(job, ND_coord(aghead(e)));
 
    return DIST2(a, tp) < DIST2(a, hp);
}
 
    /* this is gruesome, but how else can we get z coord */
#define GETZ(jp,op,p,e) (nearTail(jp,p,e)?op->tail_z:op->head_z) 
 
static void vrml_bezier(GVJ_t *job, pointf *A, size_t n, int filled) {
    (void)filled;
 
    obj_state_t *obj = job->obj;
    edge_t *e = obj->u.e;
    double fstz, sndz;
    pointf p1, V[4];
    int step;
    state_t *state = job->context;
 
    assert(e);
 
    fstz = state->Fstz = obj->tail_z; 
    sndz = state->Sndz = obj->head_z;
    if (straight(A, n)) {
        doSegment (job, A, gvrender_ptf(job, ND_coord(agtail(e))),state->Fstz,gvrender_ptf(job, ND_coord(aghead(e))),state->Sndz);
        return;
    }
 
    gvputs(job,   "Shape { geometry Extrusion  {\n"
                  "  spine [");
    V[3] = A[0];
    for (size_t i = 0; i + 3 < n; i += 3) {
        V[0] = V[3];
        for (size_t j = 1; j <= 3; j++)
            V[j] = A[i + j];
        for (step = 0; step <= BEZIERSUBDIVISION; step++) {
            p1 = Bezier(V, (double)step / BEZIERSUBDIVISION, NULL, NULL);
            gvprintf(job, " %.3f %.3f %.3f", p1.x, p1.y,
                    interpolate_zcoord(job, p1, A[0], fstz, A[n - 1], sndz));
        }
    }
    gvputs(job,   " ]\n");
    gvprintf(job, "  crossSection [ %.3f %.3f, %.3f %.3f, %.3f %.3f, %.3f %.3f ]\n",
            obj->penwidth, obj->penwidth, -obj->penwidth,
            obj->penwidth, -obj->penwidth, -obj->penwidth,
            obj->penwidth, -obj->penwidth);
    gvputs(job,   "}\n");
    gvprintf(job, " appearance DEF E%d Appearance {\n", AGSEQ(e));
    gvputs(job,   "   material Material {\n"
                  "   ambientIntensity 0.33\n");
    gvprintf(job, "   diffuseColor %.3f %.3f %.3f\n",
            obj->pencolor.u.rgba[0] / 255.,
            obj->pencolor.u.rgba[1] / 255.,
            obj->pencolor.u.rgba[2] / 255.);
    gvputs(job,   "   }\n"
                  " }\n"
                  "}\n");
}
 
static void doArrowhead (GVJ_t *job, pointf * A)
{
    obj_state_t *obj = job->obj;
    edge_t *e = obj->u.e;
    double rad, ht, y;
    pointf p0;      /* center of triangle base */
    state_t *state = job->context;
 
    p0.x = (A[0].x + A[2].x)/2.0;
    p0.y = (A[0].y + A[2].y)/2.0;
    rad = DIST(A[0],A[2])/2.0;
    ht = DIST(p0,A[1]);
 
    y = (state->CylHt + ht)/2.0;
 
    gvputs(job,   "Transform {\n");
    if (nearTail (job, A[1], e)) {
        state->TailHt = ht;
        gvprintf(job, "  translation 0 %.3f 0\n", -y);
        gvprintf(job, "  rotation 0 0 1 %.3f\n", M_PI);
    }
    else {
        state->HeadHt = ht;
        gvprintf(job, "  translation 0 %.3f 0\n", y);
    }
    gvputs(job,   "  children [\n"
                  "    Shape {\n");
    gvprintf(job, "      geometry Cone {bottomRadius %.3f height %.3f }\n",
        rad, ht);
    gvputs(job,   "      appearance Appearance {\n"
                  "        material Material {\n"
                  "          ambientIntensity 0.33\n");
    gvprintf(job, "          diffuseColor %.3f %.3f %.3f\n",
            obj->pencolor.u.rgba[0] / 255.,
            obj->pencolor.u.rgba[1] / 255.,
            obj->pencolor.u.rgba[2] / 255.);
    gvputs(job,   "        }\n"
                  "      }\n"
                  "    }\n"
                  "  ]\n"
                  "}\n");
}
 
static void vrml_polygon(GVJ_t *job, pointf *A, size_t np, int filled) {
    obj_state_t *obj = job->obj;
    node_t *n;
    edge_t *e;
    double z = obj->z;
    pointf p, mp;
    gdPoint *points;
    int pen;
    double theta;
    state_t *state = job->context;
 
    switch (obj->type) {
    case ROOTGRAPH_OBJTYPE:
        gvprintf(job, " Background { skyColor %.3f %.3f %.3f }\n",
            obj->fillcolor.u.rgba[0] / 255.,
            obj->fillcolor.u.rgba[1] / 255.,
            obj->fillcolor.u.rgba[2] / 255.);
        state->Saw_skycolor = true;
        break;
    case CLUSTER_OBJTYPE:
        break;
    case NODE_OBJTYPE:
        n = obj->u.n;
        pen = set_penstyle(job, state->im);
        points = gv_calloc(np, sizeof(gdPoint));
        for (size_t i = 0; i < np; i++) {
            mp = vrml_node_point(job, n, A[i]);
            points[i].x = ROUND(mp.x);
            points[i].y = ROUND(mp.y);
        }
        assert(np <= INT_MAX);
        if (filled)
            gdImageFilledPolygon(state->im, points, (int)np, color_index(state->im, obj->fillcolor));
        gdImagePolygon(state->im, points, (int)np, pen);
        free(points);
 
        gvputs(job,   "Shape {\n"
                      "  appearance Appearance {\n"
                      "    material Material {\n"
                      "      ambientIntensity 0.33\n"
                      "        diffuseColor 1 1 1\n"
                      "    }\n");
        gvprintf(job, "    texture ImageTexture { url \"node%d.png\" }\n", AGSEQ(n));
        gvputs(job,   "  }\n"
                      "  geometry Extrusion {\n"
                      "    crossSection [");
        for (size_t i = 0; i < np; i++) {
            p.x = A[i].x - ND_coord(n).x;
            p.y = A[i].y - ND_coord(n).y;
            gvprintf(job, " %.3f %.3f,", p.x, p.y);
        }
        p.x = A[0].x - ND_coord(n).x;
        p.y = A[0].y - ND_coord(n).y;
        gvprintf(job, " %.3f %.3f ]\n", p.x, p.y);
        gvprintf(job, "    spine [ %.5g %.5g %.5g, %.5g %.5g %.5g ]\n",
                ND_coord(n).x, ND_coord(n).y, z - .01,
                ND_coord(n).x, ND_coord(n).y, z + .01);
        gvputs(job,   "  }\n"
                      "}\n");
        break;
    case EDGE_OBJTYPE:
        e = obj->u.e;
        if (np != 3) {
            static atomic_flag flag;
            if (!atomic_flag_test_and_set(&flag)) {
                agwarningf(
                  "vrml_polygon: non-triangle arrowheads not supported - ignoring\n");
            }
        }
        if (state->IsSegment) {
            doArrowhead (job, A);
            return;
        }
        p.x = p.y = 0.0;
        for (size_t i = 0; i < np; i++) {
            p.x += A[i].x;
            p.y += A[i].y;
        }
        p.x /= (int)np;
        p.y /= (int)np;
 
        /* it is bad to know that A[1] is the aiming point, but we do */
        theta =
            atan2((A[0].y + A[2].y) / 2.0 - A[1].y,
                  (A[0].x + A[2].x) / 2.0 - A[1].x) + M_PI / 2.0;
 
        z = GETZ(job,obj,p,e);
 
        /* FIXME: arrow vector ought to follow z coord of Bézier */
        gvputs(job,   "Transform {\n");
        gvprintf(job, "  translation %.3f %.3f %.3f\n", p.x, p.y, z);
        gvputs(job,   "  children [\n"
                      "    Transform {\n");
        gvprintf(job, "      rotation 0 0 1 %.3f\n", theta);
        gvputs(job,   "      children [\n"
                      "        Shape {\n");
        gvprintf(job, "          geometry Cone {bottomRadius %.3f height %.3f }\n",
                obj->penwidth * 2.5, obj->penwidth * 10.0);
        gvprintf(job, "          appearance USE E%d\n", AGSEQ(e));
        gvputs(job,   "        }\n"
                      "      ]\n"
                      "    }\n"
                      "  ]\n"
                      "}\n");
        break;
    default:
        UNREACHABLE();
    }
}
 
static void doSphere(GVJ_t *job, pointf p, double z, double rx) {
    obj_state_t *obj = job->obj;
 
    gvputs(job,   "Transform {\n");
    gvprintf(job, "  translation %.3f %.3f %.3f\n", p.x, p.y, z);
    gvprintf(job, "  scale %.3f %.3f %.3f\n", rx, rx, rx);
    gvputs(job,   "  children [\n"
                  "    Transform {\n"
                  "      children [\n"
                  "        Shape {\n"
                  "          geometry Sphere { radius 1.0 }\n"
                  "          appearance Appearance {\n"
                  "            material Material {\n"
                  "              ambientIntensity 0.33\n");
    gvprintf(job, "              diffuseColor %.3f %.3f %.3f\n", 
            obj->pencolor.u.rgba[0] / 255.,
            obj->pencolor.u.rgba[1] / 255.,
            obj->pencolor.u.rgba[2] / 255.);
    gvputs(job,   "            }\n"
                  "          }\n"
                  "        }\n"
                  "      ]\n"
                  "    }\n"
                  "  ]\n"
                  "}\n");
}
 
static void vrml_ellipse(GVJ_t * job, pointf * A, int filled)
{
    obj_state_t *obj = job->obj;
    node_t *n;
    edge_t *e;
    double z = obj->z;
    double rx, ry;
    int dx, dy;
    pointf npf, nqf;
    point np;
    int pen;
    state_t *state = job->context;
 
    rx = A[1].x - A[0].x;
    ry = A[1].y - A[0].y;
 
    switch (obj->type) {
    case ROOTGRAPH_OBJTYPE:
    case CLUSTER_OBJTYPE:
        break;
    case NODE_OBJTYPE:
        n = obj->u.n;
        if (shapeOf(n) == SH_POINT) {
            doSphere(job, A[0], z, rx);
            return;
        }
        pen = set_penstyle(job, state->im);
 
        npf = vrml_node_point(job, n, A[0]);
        nqf = vrml_node_point(job, n, A[1]);
 
        dx = ROUND(2 * (nqf.x - npf.x));
        dy = ROUND(2 * (nqf.y - npf.y));
 
        PF2P(npf, np);
 
        if (filled)
            gdImageFilledEllipse(state->im, np.x, np.y, dx, dy, color_index(state->im, obj->fillcolor));
        gdImageArc(state->im, np.x, np.y, dx, dy, 0, 360, pen);
 
        gvputs(job,   "Transform {\n");
        gvprintf(job, "  translation %.3f %.3f %.3f\n", A[0].x, A[0].y, z);
        gvprintf(job, "  scale %.3f %.3f 1\n", rx, ry);
        gvputs(job,   "  children [\n"
                      "    Transform {\n"
                      "      rotation 1 0 0   1.57\n"
                      "      children [\n"
                      "        Shape {\n"
                      "          geometry Cylinder { side FALSE }\n"
                      "          appearance Appearance {\n"
                      "            material Material {\n"
                      "              ambientIntensity 0.33\n"
                      "              diffuseColor 1 1 1\n"
                      "            }\n");
        gvprintf(job, "            texture ImageTexture { url \"node%d.png\" }\n", AGSEQ(n));
        gvputs(job,   "          }\n"
                      "        }\n"
                      "      ]\n"
                      "    }\n"
                      "  ]\n"
                      "}\n");
        break;
    case EDGE_OBJTYPE:
        e = obj->u.e;
        z = GETZ(job,obj,A[0],e);
 
        gvputs(job,   "Transform {\n");
        gvprintf(job, "  translation %.3f %.3f %.3f\n", A[0].x, A[0].y, z);
        gvputs(job,   "  children [\n"
                      "    Shape {\n");
        gvprintf(job, "      geometry Sphere {radius %.3f }\n", rx);
        gvprintf(job, "      appearance USE E%d\n", AGSEQ(e));
        gvputs(job,   "    }\n"
                      "  ]\n"
                      "}\n");
        break;
    default:
        UNREACHABLE();
    }
}
 
static gvrender_engine_t vrml_engine = {
    vrml_begin_job,
    vrml_end_job,
    0,                          /* vrml_begin_graph */
    0,                          /* vrml_end_graph */
    0,                          /* vrml_begin_layer */
    0,                          /* vrml_end_layer */
    vrml_begin_page,
    vrml_end_page,
    0,                          /* vrml_begin_cluster */
    0,                          /* vrml_end_cluster */
    0,                          /* vrml_begin_nodes */
    0,                          /* vrml_end_nodes */
    0,                          /* vrml_begin_edges */
    0,                          /* vrml_end_edges */
    vrml_begin_node,
    vrml_end_node,
    vrml_begin_edge,
    vrml_end_edge,
    0,                          /* vrml_begin_anchor */
    0,                          /* vrml_end_anchor */
    0,                          /* vrml_begin_label */
    0,                          /* vrml_end_label */
    vrml_textspan,
    0,                          /* vrml_resolve_color */
    vrml_ellipse,
    vrml_polygon,
    vrml_bezier,
    0,                          /* vrml_polyline  - FIXME */
    0,                          /* vrml_comment */
    0,                          /* vrml_library_shape */
};
 
static gvrender_features_t render_features_vrml = {
    GVRENDER_DOES_Z,            /* flags */
    0.,                         /* default pad - graph units */
    NULL,                       /* knowncolors */
    0,                          /* sizeof knowncolors */
    RGBA_BYTE,                  /* color_type */
};
 
static gvdevice_features_t device_features_vrml = {
    GVDEVICE_BINARY_FORMAT
      | GVDEVICE_NO_WRITER,     /* flags */
    {0.,0.},                    /* default margin - points */
    {0.,0.},                    /* default page width, height - points */
    {72.,72.},                  /* default dpi */
};
#endif                          /* HAVE_GD_PNG */
 
gvplugin_installed_t gvrender_vrml_types[] = {
#ifdef HAVE_GD_PNG
    {FORMAT_VRML, "vrml", 1, &vrml_engine, &render_features_vrml},
#endif
    {0, NULL, 0, NULL, NULL}
};
 
gvplugin_installed_t gvdevice_vrml_types[] = {
#ifdef HAVE_GD_PNG
    {FORMAT_VRML, "vrml:vrml", 1, NULL, &device_features_vrml},
#endif
    {0, NULL, 0, NULL, NULL}
};