/*
* twistoid.c
*
* FUNCTION:
* Show extrusion of open contours. Also, show how torsion is applied.
*
* HISTORY:
* -- linas Vepstas October 1991
* -- heavily modified to draw corrugated surface, Feb 1993, Linas
* -- modified to demo twistoid March 1993
* -- port to glut Linas Vepstas March 1995
*/
#include "extrusion.h"
#include <math.h>
#include <stdlib.h>
/* Some <math.h> files do not define M_PI... */
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
/* controls shape of object */
extern float lastx;
extern float lasty;
#define OPENGL_10
/* =========================================================== */
#define NUM_TOID1_PTS 5
static double toid1_points[NUM_TOID1_PTS][3];
static float toid1_colors [NUM_TOID1_PTS][3];
static double toid1_twists [NUM_TOID1_PTS];
#define TSCALE (6.0)
#define TPTS(x,y) { \
toid1_points[i][0] = TSCALE * (x); \
toid1_points[i][1] = TSCALE * (y); \
toid1_points[i][2] = TSCALE * (0.0); \
i++; \
}
#define TCOLS(r,g,b) { \
toid1_colors[i][0] = (r); \
toid1_colors[i][1] = (g); \
toid1_colors[i][2] = (b); \
i++; \
}
#define TXZERO() { \
toid1_twists[i] = 0.0; \
i++; \
}
static void init_toid1_line (void)
{
int i;
i=0;
TPTS (-1.1, 0.0);
TPTS (-1.0, 0.0);
TPTS (0.0, 0.0);
TPTS (1.0, 0.0);
TPTS (1.1, 0.0);
i=0;
TCOLS (0.8, 0.8, 0.5);
TCOLS (0.8, 0.4, 0.5);
TCOLS (0.8, 0.8, 0.3);
TCOLS (0.4, 0.4, 0.5);
TCOLS (0.8, 0.8, 0.5);
i=0;
TXZERO ();
TXZERO ();
TXZERO ();
TXZERO ();
TXZERO ();
}
/* =========================================================== */
#define SCALE 0.6
#define TWIST(x,y) { \
double ax, ay, alen; \
twistation[i][0] = SCALE * (x); \
twistation[i][1] = SCALE * (y); \
if (i!=0) { \
ax = twistation[i][0] - twistation[i-1][0]; \
ay = twistation[i][1] - twistation[i-1][1]; \
alen = 1.0 / sqrt (ax*ax + ay*ay); \
ax *= alen; ay *= alen; \
twist_normal [i-1][0] = - ay; \
twist_normal [i-1][1] = ax; \
} \
i++; \
}
#define NUM_TWIS_PTS (20)
static double twistation [NUM_TWIS_PTS][2];
static double twist_normal [NUM_TWIS_PTS][2];
static void init_tripples (void)
{
int i;
double angle;
double co, si;
/* outline of extrusion */
i=0;
/* first, draw a semi-curcular "hump" */
while (i< 11) {
angle = M_PI * ((double) i) / 10.0;
co = cos (angle);
si = sin (angle);
TWIST ((-7.0 -3.0*co), 1.8*si);
}
/* now, a zig-zag corrugation */
while (1) {
if (i >= NUM_TWIS_PTS) break;
TWIST ((-10.0 +(double) i), 0.0);
if (i >= NUM_TWIS_PTS) break;
TWIST ((-9.5 +(double) i), 1.0);
}
}
/* =========================================================== */
#define V3F(x,y,z) { \
float vvv[3]; \
vvv[0] = x; vvv[1] = y; vvv[2] = z; v3f (vvv); \
}
#define N3F(x,y,z) { \
float nnn[3]; \
nnn[0] = x; nnn[1] = y; nnn[2] = z; n3f (nnn); \
}
/* =========================================================== */
void DrawStuff_twistoid (void) {
int i;
toid1_twists[2] = (lastx-121.0) / 8.0;
i=3;
/*
TPTS (1.0, lasty /400.0);
TPTS (1.1, 1.1 * lasty / 400.0);
*/
TPTS (1.0, -(lasty-121.0) /200.0);
TPTS (1.1, -1.1 * (lasty-121.0) / 200.0);
#ifdef IBM_GL_32
rotate (230, 'x');
rotate (230, 'y');
scale (1.8, 1.8, 1.8);
if (mono_color) {
RGBcolor (178, 178, 204);
twist_extrusion (NUM_TWIS_PTS, twistation, twist_normal,
NULL, NUM_TOID1_PTS, toid1_points, NULL, toid1_twists);
} else {
twist_extrusion (NUM_TWIS_PTS, twistation, twist_normal,
NULL, NUM_TOID1_PTS, toid1_points, toid1_colors, toid1_twists);
}
#endif
#ifdef OPENGL_10
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glFrontFace(GL_CW); /* jwz */
/* set up some matrices so that the object spins with the mouse */
glPushMatrix ();
/* glTranslatef (0.0, 0.0, -80.0); */
/* glRotated (43.0, 1.0, 0.0, 0.0); */
/* glRotated (43.0, 0.0, 1.0, 0.0); */
glScaled (1.8, 1.8, 1.8);
gleTwistExtrusion (NUM_TWIS_PTS, twistation, twist_normal,
NULL, NUM_TOID1_PTS, toid1_points, NULL, toid1_twists);
glPopMatrix ();
#endif
}
/* =========================================================== */
void InitStuff_twistoid (void)
{
int js;
init_toid1_line ();
init_tripples ();
#ifdef IBM_GL_32
js = getjoinstyle ();
js &= ~TUBE_CONTOUR_CLOSED;
setjoinstyle (js);
#endif
#ifdef OPENGL_10
js = gleGetJoinStyle ();
js &= ~TUBE_CONTOUR_CLOSED;
gleSetJoinStyle (js);
#endif
}
/* ------------------ end of file -------------------- */
