triquad.c

Intro/: Directory containing introductory examples. HelloWorld.c A simple program that draws a bo

#include <phigs.h>			/* get HP-PHIGS definitions for C */
#include <stdio.h>			/* get standard I/O definitions */
#include <math.h>			/* link with library "-lm" */

#define Longitudes	30		/* sections along equator and... */
#define Latitudes	15		/* from pole to pole of sphere */

main()					/* file "TriQuad.c" */
{
    Pint	WorkstnID = 1;		/* workstation identifier */
    Pint	ConnID;			/* connection identifier */
    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */
    Pint	TheStructure = 1;	/* structure ID (chosen by user) */
    Pvertex3_array Sphere;		/* globe (with latitudes/longitudes) */
    Ppoint3	SpherePts[Latitudes + 1][Longitudes + 1];
    Pvertex3_list Belt;			/* strip girdling the globe */
    Ppoint3	BeltPts[62];		/* data points of belt */
    Pgcolr	Black, White;		/* working colours */
    Pvec3	Vector;			/* for various scales/translations */
    float	Theta, Phi, CosPhi;	/* working variables */
    Pmatrix3	xform;			/* transformation matrix */
    int	Longitude, Latitude, I; 	/* loop control variables */
    int	Error;				/* error-return variable */
    float	rad();			/* forward reference */

    popen_phigs((char *) stderr, 0);	/* errors go to "stderr" */
    pescape_u4("/dev/screen/phigs_window", &ConnID);
    popen_ws(WorkstnID, (void *) ConnID, WorkstnType);
    Black.colr_type = PCOLR_RGB;
    Black.colr_value.colr_rep.rgb.red	= 0.0;
    Black.colr_value.colr_rep.rgb.green = 0.0;
    Black.colr_value.colr_rep.rgb.blue	= 0.0;
    White.colr_type = PCOLR_RGB;
    White.colr_value.colr_rep.rgb.red	= 1.0;
    White.colr_value.colr_rep.rgb.green = 1.0;
    White.colr_value.colr_rep.rgb.blue	= 1.0;
    popen_struct(TheStructure);
    /*--- define the data bases --------------------------------------------*/
    Sphere.dims.size_x = Longitudes+1;
    Sphere.dims.size_y = Latitudes+1;
    Sphere.num_data_per_vertex = 0;
    for (Longitude = 0; Longitude <= Longitudes; Longitude++) {
	Theta = 360.0 * Longitude / Longitudes;
	for (Latitude = 0; Latitude <= Latitudes; Latitude++) {
	    Phi = -89.99 + 179.98 * Latitude / Latitudes;
	    CosPhi = cos(rad(Phi));
	    SpherePts[Latitude][Longitude].x = CosPhi * cos(rad(Theta));
	    SpherePts[Latitude][Longitude].y = CosPhi * sin(rad(Theta));
	    SpherePts[Latitude][Longitude].z = sin(rad(Phi));
	}
    }
    Sphere.vertex_points = &(SpherePts[0][0]);
    Sphere.vertex_colrvs.colr_reps.rgb = NULL;
    Sphere.vertex_norms = NULL;
    Sphere.vertex_data = NULL;
    Belt.num_vertices = 62;
    Belt.num_data_per_vertex = 0;
    for (Longitude = 0; Longitude <= Longitudes; Longitude++) {
	Theta = 360.0 * (Longitude+1) / Longitudes;
	BeltPts[2 * Longitude	 ].x = 1.4 * cos(rad(Theta));
	BeltPts[2 * Longitude	 ].y = 1.4 * sin(rad(Theta));
	BeltPts[2 * Longitude	 ].z = 0.15;
	BeltPts[2 * Longitude + 1].x = 1.4 * cos(rad(Theta));
	BeltPts[2 * Longitude + 1].y = 1.4 * sin(rad(Theta));
	BeltPts[2 * Longitude + 1].z = -0.15;
    }
    Belt.vertex_points = BeltPts;
    Belt.vertex_colrvs.colr_reps.rgb = NULL;
    Belt.vertex_norms = NULL;
    Belt.vertex_data = NULL;
    /*--- render the sphere and its encircling belt ------------------------*/
    pset_hlhsr_mode(WorkstnID, PHRZBF);
    pset_int_style(PSTYLE_SOLID);
    pset_int_colr(&Black);
    pset_edge_flag(PEDGE_ON);
    pset_edge_colr(&White);
    protate_x(rad(110.0), &Error, xform);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    protate_z(rad(-20.0), &Error, xform);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    Vector.delta_x = Vector.delta_y = Vector.delta_z = 0.35;
    pscale3(&Vector, &Error, xform);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    Vector.delta_x = Vector.delta_y = Vector.delta_z = 0.5;
    ptranslate3(&Vector, &Error, xform);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    pquad_mesh3_data(PCOLR_RGB, NULL, NULL, &Sphere);
    ptri_strip3_data(PCOLR_RGB, NULL, NULL, &Belt);
    pclose_struct();
    ppost_struct(WorkstnID, TheStructure, 1.0);
    pupd_ws(WorkstnID, PFLAG_PERFORM);
    pclose_ws(WorkstnID);
    pclose_phigs();
}
/****************************************************************************/
float rad(deg)
float	deg;
{
    return (deg * 3.14159265358979 / 180.0);	/* convert deg to radians */
}