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GEARS.C
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C/C++ Source or Header
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1992-10-26
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7KB
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/*
* gears.c - Create a set of gears. Each gear face has 144 vertices, and
* contains concavities. Note that the first 3 vertices of all polygons
* define the two edges of a convex section of the polygon. Background
* square floor is reflective. Some gears are clipped.
* Five light sources.
*
* Version: 2.2 (11/17/87)
* Author: Eric Haines, 3D/Eye, Inc.
*
* SIZE_FACTOR determines the number of polygons output.
* Total gears = SF**3: concave polygons = 2 * SF**3
* rectangles = 4*TEETH * SF**3
*
* SIZE_FACTOR # gears # gear faces # rectangles
* 1 1 2 144
* 2 8 16 1152
* 3 27 54 3888
* 4 64 128 9216
*/
#include <stdio.h>
#include <math.h>
#ifdef MAC
#include <console.h>
#endif
#include "def.h"
#include "lib.h"
#define SIZE_FACTOR 2
/* define number of teeth on a gear - must be a multiple of 4 */
#define TEETH 32
/* define ratio of radius taken up by teeth and the gear thickness */
#define EDGE_RATIO 0.1
#define DEPTH_RATIO 0.1
/* Create gear tooth */
static void
create_tooth(double gear_angle, double tooth_angle,
COORD4 *center, COORD4 *outer_pt,
COORD4 *inner_pt, COORD4 *edge_pts)
{
MATRIX mx ;
lib_create_rotate_matrix( mx
, Z_AXIS
, gear_angle - 0.19 * tooth_angle ) ;
lib_transform_coord( &edge_pts[0], outer_pt, mx ) ;
ADD2_COORD( edge_pts[0], *center ) ;
lib_create_rotate_matrix( mx
, Z_AXIS
, gear_angle + 0.19 * tooth_angle ) ;
lib_transform_coord( &edge_pts[1], outer_pt, mx ) ;
ADD2_COORD( edge_pts[1], *center ) ;
lib_create_rotate_matrix( mx
, Z_AXIS
, gear_angle + 0.3 * tooth_angle ) ;
lib_transform_coord( &edge_pts[2], inner_pt, mx ) ;
ADD2_COORD( edge_pts[2], *center ) ;
lib_create_rotate_matrix( mx
, Z_AXIS
, gear_angle + 0.7 * tooth_angle ) ;
lib_transform_coord( &edge_pts[3], inner_pt, mx ) ;
ADD2_COORD( edge_pts[3], *center ) ;
}
/* Create gear */
static void
create_gear(COORD4 *center, double offset_angle, double outer_radius,
double inner_radius, double thickness)
{
COORD4 side_pts[4], gear_pts[4*TEETH], outer_pt, inner_pt ;
long next_side, num_side, num_teeth ;
double gear_angle, tooth_angle ;
outer_pt.x = outer_radius ;
outer_pt.y = 0.0 ;
outer_pt.z = 0.0 ;
outer_pt.w = 1.0 ;
inner_pt.x = inner_radius ;
inner_pt.y = 0.0 ;
inner_pt.z = 0.0 ;
inner_pt.w = 1.0 ;
tooth_angle = 2.0 * PI / (double)TEETH ;
/* output gear top */
for ( num_teeth = 0 ; num_teeth < TEETH ; ++num_teeth ) {
gear_angle = offset_angle +
2.0 * PI * (double)num_teeth / (double)TEETH ;
create_tooth( gear_angle
, tooth_angle
, center
, &outer_pt
, &inner_pt
, &gear_pts[num_teeth*4]
) ;
}
lib_output_polygon(4*TEETH, gear_pts);
/* output teeth */
for ( num_side = 0 ; num_side < 4 * TEETH ; ++num_side ) {
next_side = ( num_side + 1 ) % ( 4 * TEETH ) ;
COPY_COORD( side_pts[0], gear_pts[num_side] ) ;
COPY_COORD( side_pts[1], gear_pts[num_side] ) ;
side_pts[1].z -= thickness ;
COPY_COORD( side_pts[2], gear_pts[next_side] ) ;
side_pts[2].z -= thickness ;
COPY_COORD( side_pts[3], gear_pts[next_side] ) ;
lib_output_polygon(4, side_pts);
}
/* output gear bottom */
outer_pt.z = inner_pt.z = -thickness ;
for ( num_teeth = 0 ; num_teeth < TEETH ; ++num_teeth ) {
gear_angle = offset_angle -
2.0 * PI * (double)num_teeth / (double)TEETH ;
create_tooth( gear_angle
, -tooth_angle
, center
, &outer_pt
, &inner_pt
, &gear_pts[num_teeth*4]
) ;
}
lib_output_polygon(4*TEETH, gear_pts);
}
void
main(int argc, char *argv[])
{
COORD4 back_color, gear_color ;
COORD4 center_pt, floor[4], light, offset, zero_pt ;
COORD4 from, at, up, dir;
double angle, color_scale, outer_radius, thickness ;
long ix, iy, iz ;
/* We are using Polyray */
lib_set_raytracer(OUTPUT_POLYRAY);
/* output viewpoint */
SET_COORD( from, -1.1, -2.1, 2.6 ) ;
SET_COORD( at, 0.0, 0.0, 0.0 ) ;
SET_COORD( up, 0.0, 0.0, 1.0 ) ;
lib_output_viewpoint( &from, &at, &up, 45.0, 1.0, 1.0, 256, 256);
/* output background color - UNC sky blue */
SET_COORD( back_color, 0.078, 0.361, 0.753 ) ;
lib_output_background_color( &back_color ) ;
/* output light sources */
SET_COORD4( light, 2.0, 4.0, 4.0, 0.45 ) ;
lib_output_light( &light ) ;
SET_COORD4( light, -2.0, 4.0, 3.0, 0.45 ) ;
lib_output_light( &light ) ;
SET_COORD4( light, 2.0, -2.5, 2.5, 0.45 ) ;
lib_output_light( &light ) ;
SET_COORD4( light, -1.0, -4.0, 2.0, 0.45 ) ;
lib_output_light( &light ) ;
/* just behind the eye */
SET_COORD4( light, -1.111, -2.121, 2.626, 0.45 ) ;
lib_output_light( &light ) ;
/* output floor polygon - off white */
SET_COORD( back_color, 1.0, 0.85, 0.7 ) ;
lib_output_color(&back_color, 0.1, 0.9, 0.0, 0.0, 0.0, 0.0, 0.0);
SET_COORD( floor[0], 2.0, 2.0, 0.0 ) ;
SET_COORD( floor[1], -2.0, 2.0, 0.0 ) ;
SET_COORD( floor[2], -2.0, -2.0, 0.0 ) ;
SET_COORD( floor[3], 2.0, -2.0, 0.0 ) ;
lib_output_polygon(4, floor);
outer_radius = 1.0 / ((double)SIZE_FACTOR -
(double)(SIZE_FACTOR - 1) * EDGE_RATIO / 2.0);
/* calculate first gear center */
zero_pt.x = zero_pt.y = -1.0 + outer_radius ;
zero_pt.z = 1.0 ;
/* calculate offset */
offset.x = offset.y = outer_radius * ( 2.0 - EDGE_RATIO ) ;
offset.z = -1.0 / (double)SIZE_FACTOR ;
/* create gears */
for ( iz = 0 ; iz < SIZE_FACTOR ; ++iz ) {
center_pt.z = zero_pt.z + (double)iz * offset.z ;
for ( iy = 0 ; iy < SIZE_FACTOR ; ++iy ) {
center_pt.y = zero_pt.y + (double)iy * offset.y ;
for ( ix = 0 ; ix < SIZE_FACTOR ; ++ix ) {
center_pt.x = zero_pt.x + (double)ix * offset.x ;
/* output pseudo-random gear color */
SET_COORD(gear_color,
0.01 + FRACTION( (double)(ix*3+iy*2+iz+1)*5.0/7.0 ),
0.01 + FRACTION( (double)(iy*3+iz*2+ix+1)*3.0/7.0 ),
0.01 + FRACTION( (double)(iz*3+ix*2+iy+1)*2.0/7.0 ));
color_scale = MAX3( gear_color.x, gear_color.y, gear_color.z );
gear_color.x /= color_scale ;
gear_color.y /= color_scale ;
gear_color.z /= color_scale ;
if ((ix*4 + iy*2 + iz ) % 5 == 0)
lib_output_color(&gear_color, 0.1, 0.2, 0.0, 0.0, 0.0,
0.7, 1.1);
else
lib_output_color(&gear_color, 0.2, 0.8, 0.0, 0.0, 0.0, 0.0, 0.0);
/* output gear */
angle = PI * (double)( (ix+iy+iz) % 2 ) / (double)(TEETH);
thickness = MIN( DEPTH_RATIO, 1.0 / ( 2.0 * (double)SIZE_FACTOR));
create_gear(¢er_pt, angle, outer_radius,
(1.0 - EDGE_RATIO) * outer_radius, thickness);
}
}
}
}