src/common/rglsurf.c

#ifndef lint
static const char RCSid[] = "$Id: rglsurf.c,v 3.11 2003/11/14 17:22:06 schorsch Exp $";
#endif
/*
 * Convert Radiance -> OpenGL surfaces.
 */

#include "copyright.h"

#include "radogl.h"

#ifndef NSLICES
#define NSLICES         18              /* number of quadric slices */
#endif
#ifndef NSTACKS
#define NSTACKS         10              /* number of quadric stacks */
#endif

MATREC  *curmat = NULL;                 /* current material */

static int      curpolysize = 0;        /* outputting triangles/quads */

static GLUquadricObj    *gluqo;         /* shared quadric object */
static GLUtesselator    *gluto;         /* shared tessallation object */

static char     *glu_rout = "unk";      /* active GLU routine */

#define NOPOLY()        if (curpolysize) {glEnd(); curpolysize = 0;} else


void
setmaterial(mp, cent, ispoly)   /* prepare for new material */
register MATREC *mp;
FVECT   cent;
int     ispoly;
{
        if (mp != curmat && domats) {
                NOPOLY();
                domatobj(curmat = mp, cent);
        } else if (!ispoly) {
                NOPOLY();
        }
}


double
polyarea(cent, norm, n, v)      /* compute polygon area & normal */
FVECT   cent, norm;     /* returned center and normal */
int     n;              /* number of vertices */
register FVECT  v[];    /* vertex list */
{
        FVECT   v1, v2, v3;
        double  d;
        register int    i;

        norm[0] = norm[1] = norm[2] = 0.;
        v1[0] = v[1][0] - v[0][0];
        v1[1] = v[1][1] - v[0][1];
        v1[2] = v[1][2] - v[0][2];
        for (i = 2; i < n; i++) {
                v2[0] = v[i][0] - v[0][0];
                v2[1] = v[i][1] - v[0][1];
                v2[2] = v[i][2] - v[0][2];
                fcross(v3, v1, v2);
                norm[0] += v3[0];
                norm[1] += v3[1];
                norm[2] += v3[2];
                VCOPY(v1, v2);
        }
        if (cent != NULL) {                     /* compute center also */
                cent[0] = cent[1] = cent[2] = 0.;
                for (i = n; i--; ) {
                        cent[0] += v[i][0];
                        cent[1] += v[i][1];
                        cent[2] += v[i][2];
                }
                d = 1./n;
                cent[0] *= d; cent[1] *= d; cent[2] *= d;
        }
        return(normalize(norm)*.5);
}


static void
glu_error(en)                   /* report an error as a warning */
GLenum  en;
{
        sprintf(errmsg, "GLU error %s: %s", glu_rout, gluErrorString(en));
        error(WARNING, errmsg);
}


static void
myCombine(coords, vertex_data, weight, dataOut)
register GLdouble       coords[3];
GLdouble        *vertex_data[4];
GLfloat weight[4];
GLdouble        **dataOut;
{
        register GLdouble       *newvert;

        newvert = (GLdouble *)malloc(3*sizeof(GLdouble));
        if (newvert == NULL)
                error(SYSTEM, "out of memory in myCombine");
        VCOPY(newvert, coords);         /* no data, just coordinates */
        *dataOut = newvert;
}


static void
newtess()                       /* allocate GLU tessellation object */
{
        if ((gluto = gluNewTess()) == NULL)
                error(INTERNAL, "gluNewTess failed");
        gluTessCallback(gluto, GLU_TESS_BEGIN, glBegin);
        gluTessCallback(gluto, GLU_TESS_VERTEX, glVertex3dv);
        gluTessCallback(gluto, GLU_TESS_END, glEnd);
        gluTessCallback(gluto, GLU_TESS_COMBINE, myCombine);
        gluTessCallback(gluto, GLU_TESS_ERROR, glu_error);
        gluTessProperty(gluto, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NONZERO);
}


static void
newquadric()                    /* allocate GLU quadric structure */
{
        if ((gluqo = gluNewQuadric()) == NULL)
                error(INTERNAL, "gluNewQuadric failed");
        gluQuadricDrawStyle(gluqo, GLU_FILL);
        gluQuadricCallback(gluqo, GLU_ERROR, glu_error);
}


int
o_face(o)                       /* convert a face */
register OBJREC *o;
{
        double  area;
        FVECT   norm, cent;
        register int    i;

        if ((o->oargs.nfargs < 9) | (o->oargs.nfargs % 3))
                objerror(o, USER, "bad # real arguments");
        area = polyarea(cent, norm, o->oargs.nfargs/3, (FVECT *)o->oargs.farg);
        if (area <= FTINY)
                return(0);
        if (dolights)                                   /* check for source */
                doflatsrc((MATREC *)o->os, cent, norm, area);
        setmaterial((MATREC *)o->os, cent, 1);          /* set material */
        if (o->oargs.nfargs/3 != curpolysize) {
                if (curpolysize) glEnd();
                curpolysize = o->oargs.nfargs/3;
                if (curpolysize == 3)
                        glBegin(GL_TRIANGLES);
                else if (curpolysize == 4)
                        glBegin(GL_QUADS);
        }
        glNormal3d((GLdouble)norm[0], (GLdouble)norm[1], (GLdouble)norm[2]);
        if (curpolysize > 4) {
                if (gluto == NULL) newtess();
                glu_rout = "tessellating polygon";
                gluTessNormal(gluto, (GLdouble)norm[0],
                                (GLdouble)norm[1], (GLdouble)norm[2]);
                gluTessBeginPolygon(gluto, NULL);
                gluTessBeginContour(gluto);
#ifdef SMLFLT
                error(INTERNAL, "bad code segment in o_face");
#endif
                for (i = 0; i < curpolysize; i++)
                        gluTessVertex(gluto, (GLdouble *)(o->oargs.farg+3*i),
                                        (void *)(o->oargs.farg+3*i));
                gluTessEndContour(gluto);
                gluTessEndPolygon(gluto);
                curpolysize = 0;
        } else {
                for (i = 0; i < curpolysize; i++)
                        glVertex3d((GLdouble)o->oargs.farg[3*i],
                                        (GLdouble)o->oargs.farg[3*i+1],
                                        (GLdouble)o->oargs.farg[3*i+2]);
        }
        return(0);
}


void
surfclean()                     /* clean up surface routines */
{
        setmaterial(NULL, NULL, 0);
        if (gluqo != NULL) {
                gluDeleteQuadric(gluqo);
                gluqo = NULL;
        }
        if (gluto != NULL) {
                gluDeleteTess(gluto);
                gluto = NULL;
        }
        rgl_checkerr("in surfclean");
}


int
o_sphere(o)                     /* convert a sphere */
register OBJREC *o;
{
                                        /* check arguments */
        if (o->oargs.nfargs != 4)
                objerror(o, USER, "bad # real arguments");
        if (o->oargs.farg[3] < -FTINY) {
                o->otype = o->otype==OBJ_SPHERE ? OBJ_BUBBLE : OBJ_SPHERE;
                o->oargs.farg[3] = -o->oargs.farg[3];
        } else if (o->oargs.farg[3] <= FTINY)
                return(0);
        if (dolights)
                dosphsrc((MATREC *)o->os, o->oargs.farg,
                                PI*o->oargs.farg[3]*o->oargs.farg[3]);
        setmaterial((MATREC *)o->os, o->oargs.farg, 0);
        if (gluqo == NULL) newquadric();
        glu_rout = "making sphere";
        gluQuadricOrientation(gluqo,
                        o->otype==OBJ_BUBBLE ? GLU_INSIDE : GLU_OUTSIDE);
        gluQuadricNormals(gluqo, GLU_SMOOTH);
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
                        (GLdouble)o->oargs.farg[2]);
        gluSphere(gluqo, (GLdouble)o->oargs.farg[3], NSLICES, NSTACKS);
        glPopMatrix();
        return(0);
}


int
o_cone(o)                       /* convert a cone or cylinder */
register OBJREC *o;
{
        double  x1, y1, h, d;
        FVECT   cent;
        register int    iscyl;

        iscyl = (o->otype==OBJ_CYLINDER) | (o->otype==OBJ_TUBE);
        if (o->oargs.nfargs != (iscyl ? 7 : 8))
                objerror(o, USER, "bad # real arguments");
        if (o->oargs.farg[6] < -FTINY) {
                o->oargs.farg[6] = -o->oargs.farg[6];
                if (iscyl)
                        o->otype = o->otype==OBJ_CYLINDER ?
                                        OBJ_TUBE : OBJ_CYLINDER;
                else {
                        if ((o->oargs.farg[7] = -o->oargs.farg[7]) < -FTINY)
                                objerror(o, USER, "illegal radii");
                        o->otype = o->otype==OBJ_CONE ? OBJ_CUP : OBJ_CONE;
                }
        } else if (!iscyl && o->oargs.farg[7] < -FTINY)
                objerror(o, USER, "illegal radii");
        if (o->oargs.farg[6] <= FTINY && (iscyl || o->oargs.farg[7] <= FTINY))
                return(0);
        if (!iscyl) {
                if (o->oargs.farg[6] < 0.)      /* complains for tiny neg's */
                        o->oargs.farg[6] = 0.;
                if (o->oargs.farg[7] < 0.)
                        o->oargs.farg[7] = 0.;
        }
        h = sqrt(dist2(o->oargs.farg,o->oargs.farg+3));
        if (h <= FTINY)
                return(0);
        cent[0] = .5*(o->oargs.farg[0] + o->oargs.farg[3]);
        cent[1] = .5*(o->oargs.farg[1] + o->oargs.farg[4]);
        cent[2] = .5*(o->oargs.farg[2] + o->oargs.farg[5]);
        setmaterial((MATREC *)o->os, cent, 0);
        if (gluqo == NULL) newquadric();
        glu_rout = "making cylinder";
        gluQuadricOrientation(gluqo, (o->otype==OBJ_CUP) | (o->otype==OBJ_TUBE) ?
                        GLU_INSIDE : GLU_OUTSIDE);
        gluQuadricNormals(gluqo, GLU_SMOOTH);
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
                                        /* do base translation */
        glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
                        (GLdouble)o->oargs.farg[2]);
                                        /* compute height & rotation angle */
        x1 = o->oargs.farg[1] - o->oargs.farg[4];
        y1 = o->oargs.farg[3] - o->oargs.farg[0];
        /* z1 = 0; */
        d = x1*x1 + y1*y1;
        if (d <= FTINY*FTINY)
                x1 = 1.;
        else
                d = 180./PI * asin(sqrt(d) / h);
        if (o->oargs.farg[5] < o->oargs.farg[2])
                d = 180. - d;
        if (d > FTINY)
                glRotated(d, (GLdouble)x1, (GLdouble)y1, 0.);
        gluCylinder(gluqo, o->oargs.farg[6], o->oargs.farg[iscyl ? 6 : 7],
                        h, NSLICES, 1);
        glPopMatrix();
        return(0);
}


int
o_ring(o)                       /* convert a ring */
register OBJREC *o;
{
        double  x1, y1, d, h;

        if (o->oargs.nfargs != 8)
                objerror(o, USER, "bad # real arguments");
        if (o->oargs.farg[7] < o->oargs.farg[6]) {
                register double d = o->oargs.farg[7];
                o->oargs.farg[7] = o->oargs.farg[6];
                o->oargs.farg[6] = d;
        }
        if (o->oargs.farg[6] < -FTINY)
                objerror(o, USER, "negative radius");
        if (o->oargs.farg[6] < 0.)              /* complains for tiny neg's */
                o->oargs.farg[6] = 0.;
        if (o->oargs.farg[7] - o->oargs.farg[6] <= FTINY)
                return(0);
        h = VLEN(o->oargs.farg+3);
        if (h <= FTINY)
                return(0);
        if (dolights)
                doflatsrc((MATREC *)o->os, o->oargs.farg, o->oargs.farg+3, 
                                PI*(o->oargs.farg[7]*o->oargs.farg[7] -
                                        o->oargs.farg[6]*o->oargs.farg[6]));
        setmaterial((MATREC *)o->os, o->oargs.farg, 0);
        if (gluqo == NULL) newquadric();
        glu_rout = "making disk";
        gluQuadricOrientation(gluqo, GLU_OUTSIDE);
        gluQuadricNormals(gluqo, GLU_FLAT);
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
                        (GLdouble)o->oargs.farg[2]);
                                        /* compute rotation angle */
        x1 = -o->oargs.farg[4];
        y1 = o->oargs.farg[3];
        /* z1 = 0; */
        d = x1*x1 + y1*y1;
        if (d <= FTINY*FTINY)
                x1 = 1.;
        else
                d = 180./PI * asin(sqrt(d) / h);
        if (o->oargs.farg[5] < 0.)
                d = 180. - d;
        if (d > FTINY)
                glRotated(d, (GLdouble)x1, (GLdouble)y1, 0.);
        gluDisk(gluqo, o->oargs.farg[6], o->oargs.farg[7], NSLICES, 1);
        glPopMatrix();
        return(0);
}
Revision:	3.12
Committed:	Tue Mar 30 20:40:03 2004 UTC (20 years, 1 month ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad4R1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9
Changes since 3.11:	+5 -5 lines
Log Message:	ANSI-discovered fixes thanks to Schorsh
#	User	Rev	Content
1	gwlarson	3.1	#ifndef lint
2	greg	3.12	static const char RCSid[] = "$Id: rglsurf.c,v 3.11 2003/11/14 17:22:06 schorsch Exp $";
3	gwlarson	3.1	#endif
4			/*
5			* Convert Radiance -> OpenGL surfaces.
6			*/
7
8	greg	3.5	#include "copyright.h"
9	greg	3.4
10	gwlarson	3.1	#include "radogl.h"
11
12			#ifndef NSLICES
13			#define NSLICES 18 /* number of quadric slices */
14			#endif
15			#ifndef NSTACKS
16			#define NSTACKS 10 /* number of quadric stacks */
17			#endif
18
19			MATREC curmat = NULL; / current material */
20
21			static int curpolysize = 0; /* outputting triangles/quads */
22
23			static GLUquadricObj gluqo; / shared quadric object */
24			static GLUtesselator gluto; / shared tessallation object */
25
26			static char glu_rout = "unk"; / active GLU routine */
27
28			#define NOPOLY() if (curpolysize) {glEnd(); curpolysize = 0;} else
29
30
31	greg	3.4	void
32	gwlarson	3.1	setmaterial(mp, cent, ispoly) /* prepare for new material */
33			register MATREC *mp;
34			FVECT cent;
35			int ispoly;
36			{
37			if (mp != curmat && domats) {
38			NOPOLY();
39			domatobj(curmat = mp, cent);
40	schorsch	3.11	} else if (!ispoly) {
41	gwlarson	3.1	NOPOLY();
42	schorsch	3.11	}
43	gwlarson	3.1	}
44
45
46			double
47			polyarea(cent, norm, n, v) /* compute polygon area & normal */
48			FVECT cent, norm; /* returned center and normal */
49			int n; /* number of vertices */
50			register FVECT v[]; /* vertex list */
51			{
52			FVECT v1, v2, v3;
53			double d;
54			register int i;
55
56			norm[0] = norm[1] = norm[2] = 0.;
57			v1[0] = v[1][0] - v[0][0];
58			v1[1] = v[1][1] - v[0][1];
59			v1[2] = v[1][2] - v[0][2];
60			for (i = 2; i < n; i++) {
61			v2[0] = v[i][0] - v[0][0];
62			v2[1] = v[i][1] - v[0][1];
63			v2[2] = v[i][2] - v[0][2];
64			fcross(v3, v1, v2);
65			norm[0] += v3[0];
66			norm[1] += v3[1];
67			norm[2] += v3[2];
68			VCOPY(v1, v2);
69			}
70			if (cent != NULL) { /* compute center also */
71			cent[0] = cent[1] = cent[2] = 0.;
72			for (i = n; i--; ) {
73			cent[0] += v[i][0];
74			cent[1] += v[i][1];
75			cent[2] += v[i][2];
76			}
77			d = 1./n;
78			cent[0] = d; cent[1] = d; cent[2] *= d;
79			}
80			return(normalize(norm)*.5);
81			}
82
83
84	greg	3.4	static void
85	gwlarson	3.2	glu_error(en) /* report an error as a warning */
86	gwlarson	3.1	GLenum en;
87			{
88			sprintf(errmsg, "GLU error %s: %s", glu_rout, gluErrorString(en));
89			error(WARNING, errmsg);
90			}
91
92
93	gwlarson	3.3	static void
94			myCombine(coords, vertex_data, weight, dataOut)
95			register GLdouble coords[3];
96			GLdouble *vertex_data[4];
97			GLfloat weight[4];
98			GLdouble **dataOut;
99			{
100			register GLdouble *newvert;
101
102			newvert = (GLdouble )malloc(3sizeof(GLdouble));
103			if (newvert == NULL)
104			error(SYSTEM, "out of memory in myCombine");
105			VCOPY(newvert, coords); /* no data, just coordinates */
106			*dataOut = newvert;
107			}
108
109
110	schorsch	3.10	static void
111	gwlarson	3.1	newtess() /* allocate GLU tessellation object */
112			{
113			if ((gluto = gluNewTess()) == NULL)
114			error(INTERNAL, "gluNewTess failed");
115	greg	3.6	gluTessCallback(gluto, GLU_TESS_BEGIN, glBegin);
116			gluTessCallback(gluto, GLU_TESS_VERTEX, glVertex3dv);
117	gwlarson	3.1	gluTessCallback(gluto, GLU_TESS_END, glEnd);
118	gwlarson	3.3	gluTessCallback(gluto, GLU_TESS_COMBINE, myCombine);
119	gwlarson	3.1	gluTessCallback(gluto, GLU_TESS_ERROR, glu_error);
120			gluTessProperty(gluto, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NONZERO);
121			}
122
123
124	schorsch	3.10	static void
125	gwlarson	3.1	newquadric() /* allocate GLU quadric structure */
126			{
127			if ((gluqo = gluNewQuadric()) == NULL)
128			error(INTERNAL, "gluNewQuadric failed");
129			gluQuadricDrawStyle(gluqo, GLU_FILL);
130			gluQuadricCallback(gluqo, GLU_ERROR, glu_error);
131			}
132
133
134	greg	3.4	int
135	gwlarson	3.1	o_face(o) /* convert a face */
136			register OBJREC *o;
137			{
138			double area;
139			FVECT norm, cent;
140			register int i;
141
142	schorsch	3.11	if ((o->oargs.nfargs < 9) \| (o->oargs.nfargs % 3))
143	gwlarson	3.1	objerror(o, USER, "bad # real arguments");
144			area = polyarea(cent, norm, o->oargs.nfargs/3, (FVECT *)o->oargs.farg);
145			if (area <= FTINY)
146	greg	3.7	return(0);
147	gwlarson	3.1	if (dolights) /* check for source */
148	greg	3.4	doflatsrc((MATREC *)o->os, cent, norm, area);
149			setmaterial((MATREC )o->os, cent, 1); / set material */
150	gwlarson	3.1	if (o->oargs.nfargs/3 != curpolysize) {
151			if (curpolysize) glEnd();
152			curpolysize = o->oargs.nfargs/3;
153			if (curpolysize == 3)
154			glBegin(GL_TRIANGLES);
155			else if (curpolysize == 4)
156			glBegin(GL_QUADS);
157			}
158			glNormal3d((GLdouble)norm[0], (GLdouble)norm[1], (GLdouble)norm[2]);
159			if (curpolysize > 4) {
160			if (gluto == NULL) newtess();
161			glu_rout = "tessellating polygon";
162			gluTessNormal(gluto, (GLdouble)norm[0],
163			(GLdouble)norm[1], (GLdouble)norm[2]);
164			gluTessBeginPolygon(gluto, NULL);
165			gluTessBeginContour(gluto);
166			#ifdef SMLFLT
167			error(INTERNAL, "bad code segment in o_face");
168			#endif
169			for (i = 0; i < curpolysize; i++)
170			gluTessVertex(gluto, (GLdouble )(o->oargs.farg+3i),
171			(void )(o->oargs.farg+3i));
172			gluTessEndContour(gluto);
173			gluTessEndPolygon(gluto);
174			curpolysize = 0;
175			} else {
176			for (i = 0; i < curpolysize; i++)
177			glVertex3d((GLdouble)o->oargs.farg[3*i],
178			(GLdouble)o->oargs.farg[3*i+1],
179			(GLdouble)o->oargs.farg[3*i+2]);
180			}
181	greg	3.7	return(0);
182	gwlarson	3.1	}
183
184
185	greg	3.4	void
186	gwlarson	3.1	surfclean() /* clean up surface routines */
187			{
188			setmaterial(NULL, NULL, 0);
189			if (gluqo != NULL) {
190			gluDeleteQuadric(gluqo);
191			gluqo = NULL;
192			}
193			if (gluto != NULL) {
194			gluDeleteTess(gluto);
195			gluto = NULL;
196			}
197			rgl_checkerr("in surfclean");
198			}
199
200
201	greg	3.4	int
202	gwlarson	3.1	o_sphere(o) /* convert a sphere */
203			register OBJREC *o;
204			{
205			/* check arguments */
206			if (o->oargs.nfargs != 4)
207			objerror(o, USER, "bad # real arguments");
208			if (o->oargs.farg[3] < -FTINY) {
209			o->otype = o->otype==OBJ_SPHERE ? OBJ_BUBBLE : OBJ_SPHERE;
210			o->oargs.farg[3] = -o->oargs.farg[3];
211			} else if (o->oargs.farg[3] <= FTINY)
212	greg	3.7	return(0);
213	gwlarson	3.1	if (dolights)
214	greg	3.4	dosphsrc((MATREC *)o->os, o->oargs.farg,
215	gwlarson	3.1	PIo->oargs.farg[3]o->oargs.farg[3]);
216	greg	3.4	setmaterial((MATREC *)o->os, o->oargs.farg, 0);
217	gwlarson	3.1	if (gluqo == NULL) newquadric();
218			glu_rout = "making sphere";
219			gluQuadricOrientation(gluqo,
220			o->otype==OBJ_BUBBLE ? GLU_INSIDE : GLU_OUTSIDE);
221			gluQuadricNormals(gluqo, GLU_SMOOTH);
222			glMatrixMode(GL_MODELVIEW);
223			glPushMatrix();
224			glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
225			(GLdouble)o->oargs.farg[2]);
226			gluSphere(gluqo, (GLdouble)o->oargs.farg[3], NSLICES, NSTACKS);
227			glPopMatrix();
228	greg	3.7	return(0);
229	gwlarson	3.1	}
230
231
232	greg	3.4	int
233	gwlarson	3.1	o_cone(o) /* convert a cone or cylinder */
234			register OBJREC *o;
235			{
236			double x1, y1, h, d;
237			FVECT cent;
238			register int iscyl;
239
240	schorsch	3.11	iscyl = (o->otype==OBJ_CYLINDER) \| (o->otype==OBJ_TUBE);
241	gwlarson	3.1	if (o->oargs.nfargs != (iscyl ? 7 : 8))
242	greg	3.4	objerror(o, USER, "bad # real arguments");
243	gwlarson	3.1	if (o->oargs.farg[6] < -FTINY) {
244			o->oargs.farg[6] = -o->oargs.farg[6];
245			if (iscyl)
246			o->otype = o->otype==OBJ_CYLINDER ?
247			OBJ_TUBE : OBJ_CYLINDER;
248			else {
249			if ((o->oargs.farg[7] = -o->oargs.farg[7]) < -FTINY)
250			objerror(o, USER, "illegal radii");
251			o->otype = o->otype==OBJ_CONE ? OBJ_CUP : OBJ_CONE;
252			}
253			} else if (!iscyl && o->oargs.farg[7] < -FTINY)
254			objerror(o, USER, "illegal radii");
255			if (o->oargs.farg[6] <= FTINY && (iscyl \|\| o->oargs.farg[7] <= FTINY))
256	greg	3.12	return(0);
257	gwlarson	3.3	if (!iscyl) {
258			if (o->oargs.farg[6] < 0.) /* complains for tiny neg's */
259			o->oargs.farg[6] = 0.;
260			if (o->oargs.farg[7] < 0.)
261			o->oargs.farg[7] = 0.;
262			}
263	greg	3.9	h = sqrt(dist2(o->oargs.farg,o->oargs.farg+3));
264			if (h <= FTINY)
265	greg	3.12	return(0);
266	gwlarson	3.1	cent[0] = .5*(o->oargs.farg[0] + o->oargs.farg[3]);
267			cent[1] = .5*(o->oargs.farg[1] + o->oargs.farg[4]);
268			cent[2] = .5*(o->oargs.farg[2] + o->oargs.farg[5]);
269	greg	3.4	setmaterial((MATREC *)o->os, cent, 0);
270	gwlarson	3.1	if (gluqo == NULL) newquadric();
271			glu_rout = "making cylinder";
272	schorsch	3.11	gluQuadricOrientation(gluqo, (o->otype==OBJ_CUP) \| (o->otype==OBJ_TUBE) ?
273	gwlarson	3.1	GLU_INSIDE : GLU_OUTSIDE);
274			gluQuadricNormals(gluqo, GLU_SMOOTH);
275			glMatrixMode(GL_MODELVIEW);
276			glPushMatrix();
277			/* do base translation */
278			glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
279			(GLdouble)o->oargs.farg[2]);
280			/* compute height & rotation angle */
281			x1 = o->oargs.farg[1] - o->oargs.farg[4];
282			y1 = o->oargs.farg[3] - o->oargs.farg[0];
283			/* z1 = 0; */
284	greg	3.8	d = x1x1 + y1y1;
285			if (d <= FTINY*FTINY)
286			x1 = 1.;
287			else
288			d = 180./PI * asin(sqrt(d) / h);
289	gwlarson	3.1	if (o->oargs.farg[5] < o->oargs.farg[2])
290			d = 180. - d;
291			if (d > FTINY)
292			glRotated(d, (GLdouble)x1, (GLdouble)y1, 0.);
293			gluCylinder(gluqo, o->oargs.farg[6], o->oargs.farg[iscyl ? 6 : 7],
294			h, NSLICES, 1);
295			glPopMatrix();
296	greg	3.7	return(0);
297	gwlarson	3.1	}
298
299
300	greg	3.4	int
301	gwlarson	3.1	o_ring(o) /* convert a ring */
302			register OBJREC *o;
303			{
304	greg	3.8	double x1, y1, d, h;
305	gwlarson	3.1
306			if (o->oargs.nfargs != 8)
307	greg	3.4	objerror(o, USER, "bad # real arguments");
308	gwlarson	3.1	if (o->oargs.farg[7] < o->oargs.farg[6]) {
309			register double d = o->oargs.farg[7];
310			o->oargs.farg[7] = o->oargs.farg[6];
311			o->oargs.farg[6] = d;
312			}
313			if (o->oargs.farg[6] < -FTINY)
314			objerror(o, USER, "negative radius");
315			if (o->oargs.farg[6] < 0.) /* complains for tiny neg's */
316			o->oargs.farg[6] = 0.;
317			if (o->oargs.farg[7] - o->oargs.farg[6] <= FTINY)
318	greg	3.12	return(0);
319	greg	3.9	h = VLEN(o->oargs.farg+3);
320			if (h <= FTINY)
321	greg	3.12	return(0);
322	gwlarson	3.1	if (dolights)
323	greg	3.4	doflatsrc((MATREC *)o->os, o->oargs.farg, o->oargs.farg+3,
324	gwlarson	3.1	PI(o->oargs.farg[7]o->oargs.farg[7] -
325			o->oargs.farg[6]*o->oargs.farg[6]));
326	greg	3.4	setmaterial((MATREC *)o->os, o->oargs.farg, 0);
327	gwlarson	3.1	if (gluqo == NULL) newquadric();
328			glu_rout = "making disk";
329			gluQuadricOrientation(gluqo, GLU_OUTSIDE);
330			gluQuadricNormals(gluqo, GLU_FLAT);
331			glMatrixMode(GL_MODELVIEW);
332			glPushMatrix();
333			glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
334			(GLdouble)o->oargs.farg[2]);
335			/* compute rotation angle */
336			x1 = -o->oargs.farg[4];
337			y1 = o->oargs.farg[3];
338			/* z1 = 0; */
339	greg	3.8	d = x1x1 + y1y1;
340			if (d <= FTINY*FTINY)
341			x1 = 1.;
342			else
343			d = 180./PI * asin(sqrt(d) / h);
344	gwlarson	3.1	if (o->oargs.farg[5] < 0.)
345			d = 180. - d;
346			if (d > FTINY)
347			glRotated(d, (GLdouble)x1, (GLdouble)y1, 0.);
348			gluDisk(gluqo, o->oargs.farg[6], o->oargs.farg[7], NSLICES, 1);
349			glPopMatrix();
350	greg	3.7	return(0);
351	gwlarson	3.1	}