/*
* screw.c
*
* FUNCTION:
* Draws a screw shape.
*
* HISTORY:
* -- created by Linas Vepstas October 1991
* -- heavily modified to draw more texas shapes, Feb 1993, Linas
* -- converted to use GLUT -- December 1995, Linas
*
*/
#include "extrusion.h"
#include <stdlib.h>
#include <math.h>
/* =========================================================== */
#define SCALE 1.3
#define CONTOUR(x,y) { \
double ax, ay, alen; \
contour[i][0] = SCALE * (x); \
contour[i][1] = SCALE * (y); \
if (i!=0) { \
ax = contour[i][0] - contour[i-1][0]; \
ay = contour[i][1] - contour[i-1][1]; \
alen = 1.0 / sqrt (ax*ax + ay*ay); \
ax *= alen; ay *= alen; \
norms [i-1][0] = ay; \
norms [i-1][1] = -ax; \
} \
i++; \
}
#define NUM_PTS (25)
static double contour [NUM_PTS][2];
static double norms [NUM_PTS][2];
static void init_contour (void)
{
int i;
/* outline of extrusion */
i=0;
CONTOUR (1.0, 1.0);
CONTOUR (1.0, 2.9);
CONTOUR (0.9, 3.0);
CONTOUR (-0.9, 3.0);
CONTOUR (-1.0, 2.9);
CONTOUR (-1.0, 1.0);
CONTOUR (-2.9, 1.0);
CONTOUR (-3.0, 0.9);
CONTOUR (-3.0, -0.9);
CONTOUR (-2.9, -1.0);
CONTOUR (-1.0, -1.0);
CONTOUR (-1.0, -2.9);
CONTOUR (-0.9, -3.0);
CONTOUR (0.9, -3.0);
CONTOUR (1.0, -2.9);
CONTOUR (1.0, -1.0);
CONTOUR (2.9, -1.0);
CONTOUR (3.0, -0.9);
CONTOUR (3.0, 0.9);
CONTOUR (2.9, 1.0);
CONTOUR (1.0, 1.0); /* repeat so that last normal is computed */
}
/* =========================================================== */
/* controls shape of object */
extern float lastx;
extern float lasty;
void InitStuff_screw (void)
{
int style;
/* configure the pipeline */
style = TUBE_JN_CAP;
style |= TUBE_CONTOUR_CLOSED;
style |= TUBE_NORM_FACET;
style |= TUBE_JN_ANGLE;
gleSetJoinStyle (style);
init_contour();
}
/* =========================================================== */
void DrawStuff_screw (void) {
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3f (0.5, 0.6, 0.6);
/* set up some matrices so that the object spins with the mouse */
glPushMatrix ();
/* glTranslatef (0.0, 0.0, -80.0); */
/* glRotatef (130.0, 0.0, 1.0, 0.0); */
/* glRotatef (65.0, 1.0, 0.0, 0.0); */
/* draw the brand and the handle */
gleScrew (20, contour, norms,
NULL, -6.0, 9.0, lasty);
glPopMatrix ();
}
/* ===================== END OF FILE ================== */
