/* ====================================================================== rings.c Ernie Wright 02 Jun 05 This version has been modified to fit your TV. ====================================================================== */ /* * rings.c - Create objects with 6 pentagonal rings which connect the midpoints * of the edges of a dodecahedron. A pyramid of these objects is formed, * which the viewer looks upon from the point. A plane is placed behind * the pyramid for shadows. Three light sources. * * Author: Eric Haines * * size_factor determines the number of objects output. * Each object has 30 cylinders and 30 spheres. * Total objects = SF*SF + (SF-1)*(SF-1) + ... + 1 plus 1 backdrop square. * formula for # of spheres or cylinders = 5*SF*(SF+1)*(2*SF+1) * * size_factor # spheres # cylinders # squares * 1 30 30 1 * 2 150 150 1 * 3 420 420 1 * * 7 4200 4200 1 */ #include #include #include #include "lwmod.h" #include "def.h" #include "lib.h" static int size_factor; static int output_format = 0; static char *spdName = "Rings"; /* if spread out is > 1, succeeding layers spread out more */ #define SPREAD_OUT 1 /* Create the set of 30 points needed to generate the rings */ static void create_dodec( minor_radius, vertex ) double minor_radius ; COORD3 vertex[30] ; { int num_vertex, num_pentagon ; double scale, x_rotation, z_rotation ; COORD3 temp_vertex ; MATRIX x_matrix, z_matrix ; /* scale object to fit in a sphere of radius 1 */ scale = 1.0 / ( 1.0 + minor_radius ) ; /* * define one pentagon as on the XY plane, with points starting along +X * and N fifths of the way around the Z axis. */ for ( num_vertex = 0 ; num_vertex < 5 ; ++num_vertex ) { vertex[num_vertex][X] = scale * cos((double)num_vertex * 2.0*PI/5.0 ) ; vertex[num_vertex][Y] = scale * sin((double)num_vertex * 2.0*PI/5.0 ) ; vertex[num_vertex][Z] = 0.0 ; vertex[num_vertex][W] = 1.0 ; } /* * find the rotation angle (in radians) along the X axis: * angle between two adjacent dodecahedron faces. */ x_rotation = 2.0 * acos( cos( (double)(PI/3.0) ) / sin( (double)(PI/5.0) ) ) ; lib_create_rotate_matrix( x_matrix, X_AXIS, x_rotation ) ; /* * Find each of the other 5 pentagons: rotate along the X axis, * then rotate on the Z axis. */ for ( num_pentagon = 1 ; num_pentagon < 6 ; ++num_pentagon ) { /* * find the rotation angle (in radians) along the Z axis: * 1/10th plus N fifths of the way around * 2 * PI. */ z_rotation = PI*( 2.0*(double)(num_pentagon-1)+1.0 ) / 5.0 ; lib_create_rotate_matrix( z_matrix, Z_AXIS, z_rotation ) ; for ( num_vertex = 0 ; num_vertex < 5 ; ++num_vertex ) { lib_transform_point( temp_vertex , vertex[num_vertex] , x_matrix ) ; lib_transform_point( vertex[5*num_pentagon+num_vertex] , temp_vertex , z_matrix ) ; } } } void spdRings( int sf ) { int prev_elem, num_elem, num_depth, num_objx, num_objz, ci; double radius, spread, y_diff, xz_diff ; COORD4 base_pt, apex_pt, light ; COORD3 from, at, up ; COORD3 wvec ; COORD3 back_color, ring_color[6] ; COORD3 wall[4], offset, dodec[30] ; double lscale; size_factor = sf; radius = 0.07412 ; /* cone and sphere radius */ /* calculate spread of objects */ spread = 1 / sin( (double)( PI/8.0 ) ) ; if ( SPREAD_OUT <= spread ) { y_diff = spread / SPREAD_OUT ; xz_diff = 1.0 ; } else { y_diff = 1.0 ; xz_diff = SPREAD_OUT / spread ; } /* output background color - UNC sky blue */ /* NOTE: Do this BEFORE lib_output_viewpoint(), for display_init() */ /* note that the background color should never be seen */ SET_COORD3( back_color, 0.078, 0.361, 0.753 ) ; lib_output_background_color( back_color ) ; /* output viewpoint */ SET_COORD3( from, -1.0, -spread, 0.5 ) ; SET_COORD3( at, from[X], from[Y] + 1.0, from[Z] ) ; SET_COORD3( up, 0.0, 0.0, 1.0 ) ; lib_output_viewpoint( from, at, up, 45.0, 1.0, 1.0, 512, 512); /* * For raytracers that don't scale the light intensity, * we will do it for them */ #define NUM_LIGHTS 3 lscale = 1.0 / sqrt(NUM_LIGHTS); /* output light source */ SET_COORD4( light, 3.0, -spread, 3.0, lscale ) ; lib_output_light( light ) ; SET_COORD4( light, -4.0, -spread, 1.0, lscale ) ; lib_output_light( light ) ; SET_COORD4( light, 2.0, -spread, -4.0, lscale ) ; lib_output_light( light ) ; /* output wall polygon - white */ SET_COORD3( back_color, 1.0, 1.0, 1.0 ) ; lib_output_color(spdName, 1, back_color, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0); /* just spans 45 degree view + 1% */ wvec[Y] = y_diff * ( size_factor + 1 ) ; wvec[X] = wvec[Z] = 1.01 * ( wvec[Y] - from[Y] ) * tan( PI / 8.0 ) ; SET_COORD3( wall[0], wvec[X]+from[X], wvec[Y], wvec[Z]+from[Z] ) ; SET_COORD3( wall[1], -wvec[X]+from[X], wvec[Y], wvec[Z]+from[Z] ) ; SET_COORD3( wall[2], -wvec[X]+from[X], wvec[Y], -wvec[Z]+from[Z] ) ; SET_COORD3( wall[3], wvec[X]+from[X], wvec[Y], -wvec[Z]+from[Z] ) ; lib_output_polygon( 4, wall ) ; /* set up ring colors - RGB and complements */ SET_COORD3( ring_color[0], 1.0, 0.0, 0.0 ) ; SET_COORD3( ring_color[1], 0.0, 1.0, 0.0 ) ; SET_COORD3( ring_color[2], 0.0, 0.0, 1.0 ) ; SET_COORD3( ring_color[3], 0.0, 1.0, 1.0 ) ; SET_COORD3( ring_color[4], 1.0, 0.0, 1.0 ) ; SET_COORD3( ring_color[5], 1.0, 1.0, 0.0 ) ; create_dodec( radius, dodec ) ; /* radius of osculating cylinders and spheres (no derivation given) */ base_pt[W] = apex_pt[W] = radius ; lwMonitorBegin( spdName, "Creating rings.", size_factor ); for ( num_depth = 0 ; num_depth < size_factor ; ++num_depth ) { if ( lwMonitorStep( 1 )) return; offset[Y] = y_diff * (double)(num_depth+1) ; for ( num_objz = 0 ; num_objz <= num_depth ; ++num_objz ) { offset[Z] = xz_diff * (double)(2*num_objz - num_depth) ; for ( num_objx = 0 ; num_objx <= num_depth ; ++num_objx ) { offset[X] = xz_diff * (double)(2*num_objx - num_depth) ; for ( num_elem = 0 ; num_elem < 30 ; ++num_elem ) { ci = num_elem / 5; COPY_COORD3( base_pt, dodec[num_elem] ) ; ADD2_COORD3( base_pt, offset ) ; if ( num_elem%5 == 0 ) { prev_elem = num_elem + 4 ; /* new ring beginning - output color */ lib_output_color( spdName, ci + 2, ring_color[ ci ], 0.0, 0.5, 0.2, 0.3, 37.0, 0.0, 0.0 ); } else { prev_elem = num_elem - 1 ; } COPY_COORD3( apex_pt, dodec[prev_elem] ) ; ADD2_COORD3( apex_pt, offset ) ; lib_output_cylcone( base_pt, apex_pt, output_format ) ; lib_output_sphere( base_pt, output_format ) ; } } } } lwMonitorDone(); }