#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 SetGColr(Vl,Rd,Gr,Bl)	Vl.colr_type = PCOLR_RGB;		\				Vl.colr_value.colr_rep.rgb.red   = Rd;	\				Vl.colr_value.colr_rep.rgb.green = Gr;	\				Vl.colr_value.colr_rep.rgb.blue  = Bl#define deg 	*3.14159265358979323/180/* convert deg to rad */#define	FirstColour	0.0, 0.0, 0.0	/* dimmest colour: black */#define	LastColour	1.0, 1.0, 1.0	/* brightest colour: white */main()					/* file "GrayRamp.c" */{    Pint	WorkstnID = 1;		/* workstation identifier */    Pint	ConnID;			/* connection identifier */    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */    Pint	SphereStruc=1, Scene=2;	/* structure IDs (chosen by user) */    static Pfloat WeightVecVals[3] = {0.30, 0.59, 0.11};    static Pfloat_list WeightVector = {3, WeightVecVals};    static Pint	Lights[3] = {1, 2, 3};	/* light-state array */    Pint_list	LightsOn, LightsOff;	/* light-state variables */    Pmatrix3	Matrix;			/* transformation matrix */    static Ppoint3 Loc    = {0.0, 0.0, 0.0};	/* for building a matrix */    static Pvec3   Shift1 = {0.3, 0.7, 0.7};	/* for building a matrix */    static Pvec3   Shift2 = {0.7, 0.3, 0.3};	/* for building a matrix */    static Pvec3   Scale  = {0.3, 0.3, 0.3};	/* for building a matrix */    Pint	Error;			/* error-return variable */    popen_phigs((char *) stderr, 0);	/* errors go to "stderr" */    pescape_u4("/dev/screen/phigs_window", &ConnID);    popen_ws(WorkstnID, (void *) ConnID, WorkstnType);    pescape_u250(WorkstnID, 0);		/* set colour environment: direct */    popen_struct(SphereStruc);    CreateSphere(32, 16);		/* define the sphere structure */    pclose_struct();    DefineLightSources(WorkstnID);	/* define all lights */    popen_struct(Scene);    DefineColourRamp(WorkstnID, FirstColour, LastColour, 101, 1,      &WeightVector);    pset_colr_map_ind(1);    pset_facet_cull_mode(PFACET_CULL_BACKFACING);    pset_int_style(PSTYLE_SOLID);    pset_refl_model(PREFL_MODEL_AMB_DIFF_SPEC_REFL);    pset_int_shad_method(PINT_SHAD_METHOD_NONE);    SetReflectanceProperties(WorkstnID,      1.0, 1.0, 1.0,			/* amb/diff/spec reflections */      1.0, 1.0, 1.0,			/* specular colour */      20.0);				/* specular exponent */    LightsOn.num_ints = 3;    LightsOn.ints = Lights;    LightsOff.num_ints = 0;    pset_light_source_st(&LightsOn, &LightsOff);    pbuild_tran_matrix3(&Loc, &Shift1, -60 deg, 30 deg, -5 deg, &Scale,      &Error, Matrix);    pset_local_tran3(Matrix, PTYPE_REPLACE);    pexec_struct(SphereStruc);    pset_int_shad_method(PINT_SHAD_METHOD_COLR);    pbuild_tran_matrix3(&Loc, &Shift2, -60 deg, 30 deg, -5 deg, &Scale,      &Error, Matrix);    pset_local_tran3(Matrix, PTYPE_REPLACE);    pexec_struct(SphereStruc);    pclose_struct();    ppost_struct(WorkstnID, Scene, 1.0);    pclose_ws(WorkstnID);    pclose_phigs();}/****************************************************************************/CreateSphere(Longitudes, Latitudes)Pint	Longitudes, Latitudes;{    /*--- arbitrary limit of 50 for number of latitudes and longitudes -----*/    Pfloat	Sphere[3][51][51];		    Pint	Longitude, Latitude, I;		/* loop control variables */    Pfloat	Theta, Phi, CosPhi;		/* working variables */    Ppoint3	Vertices[4];			/* vertex XYZ data */    Pfacet	Facets;				/* facet data */    Pvertex3_set VertexSet;			/* vertex data */    Pvertex3_list VertexList[1];    static Prgb	Red       = {1.0, 0.0, 0.0};	/* RGB for red */    static Prgb	LightBlue = {0.0, 0.5, 0.7};	/* RGB for a light blue */    /*---- define sphere's data base ----------------------------------------*/    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(Phi deg);	    Sphere[0][Longitude][Latitude] = CosPhi * cos(Theta deg);	    Sphere[1][Longitude][Latitude] = CosPhi * sin(Theta deg);	    Sphere[2][Longitude][Latitude] = sin(Phi deg);	}    }    /*--- create the sphere out of unicolour patches -----------------------*/    Facets.num_data_per_facet = 0;    Facets.facet_norm = NULL;    Facets.facet_data = NULL;    VertexSet.num_lists = 1;    VertexSet.vertices = VertexList;    VertexList[0].num_vertices = 4;    VertexList[0].num_data_per_vertex = 0;    VertexList[0].vertex_points = Vertices;    VertexList[0].vertex_colrvs.colr_reps.rgb = NULL;    VertexList[0].vertex_norms = (Pvec3 *) Vertices;    VertexList[0].vertex_data = NULL;    for (Latitude = 0; Latitude < Latitudes; Latitude++) {	for (Longitude = 0; Longitude < Longitudes; Longitude++) {	    Vertices[0].x = Sphere[0][Longitude][Latitude];	    Vertices[0].y = Sphere[1][Longitude][Latitude];	    Vertices[0].z = Sphere[2][Longitude][Latitude];	    Vertices[1].x = Sphere[0][Longitude + 1][Latitude];	    Vertices[1].y = Sphere[1][Longitude + 1][Latitude];	    Vertices[1].z = Sphere[2][Longitude + 1][Latitude];	    Vertices[2].x = Sphere[0][Longitude + 1][Latitude + 1];	    Vertices[2].y = Sphere[1][Longitude + 1][Latitude + 1];	    Vertices[2].z = Sphere[2][Longitude + 1][Latitude + 1];	    Vertices[3].x = Sphere[0][Longitude][Latitude + 1];	    Vertices[3].y = Sphere[1][Longitude][Latitude + 1];	    Vertices[3].z = Sphere[2][Longitude][Latitude + 1];	    if ((Longitude >> 1) & 1)		Facets.facet_colrv = (void *) &LightBlue;	    else		Facets.facet_colrv = (void *) &Red;	    pfill_area_set3_data(PCOLR_RGB, &Facets, NULL, &VertexSet);	}    }    return;}/****************************************************************************/SetReflectanceProperties(WorkstnID, AmbientRefl, DiffuseRefl, SpecRefl,  SpecR, SpecG, SpecB, SpecExp)Pint	WorkstnID;		/* workstation ID */Pfloat	AmbientRefl;		/* ambient refl. coefficient (0.0->1.0) */Pfloat	DiffuseRefl;		/* diffuse refl. coefficient (0.0->1.0) */Pfloat	SpecRefl;		/* specular refl coefficient (0.0->1.0) */Pfloat	SpecR, SpecG, SpecB;	/* specular reflection colour */Pfloat	SpecExp;		/* specular exponent ("shininess") */{    Prefl_prop	ReflProp;        ReflProp.type = PREFL_PROPS_SIMPLE_REFL;    ReflProp.data.simple_refl.amb_coeff  = AmbientRefl;    ReflProp.data.simple_refl.diff_coeff = DiffuseRefl;    ReflProp.data.simple_refl.spec_coeff = SpecRefl;    ReflProp.data.simple_refl.spec_colr.colr_type = PCOLR_RGB;    ReflProp.data.simple_refl.spec_colr.colr_value.colr_rep.rgb.red   = SpecR;    ReflProp.data.simple_refl.spec_colr.colr_value.colr_rep.rgb.green = SpecG;    ReflProp.data.simple_refl.spec_colr.colr_value.colr_rep.rgb.blue  = SpecB;    ReflProp.data.simple_refl.spec_exp = SpecExp;    pset_refl_props(&ReflProp);}/****************************************************************************/DefineLightSources(WorkstnID)Pint	WorkstnID;{    DefineLightSource(WorkstnID, 1,	/* light source 1 */      PLIGHT_SOURCE_AMB,		/*   ambient */      0.4, 0.4, 0.4,			/*   colour (dark gray) */      0.0, 0.0, 0.0,			/*   position (unused) */      0.0, 0.0, 0.0,			/*   direction (unused) */      0.0, 0.0, 0.0, 0.0);		/*   conc/spread/atten (unused) */    DefineLightSource(WorkstnID, 2,	/* light source 2 */      PLIGHT_SOURCE_DIR,		/*   directional */      0.8, 0.8, 0.8,			/*   colour (dim white) */      0.0, 0.0, 0.0,			/*   position (unused) */      10.0, 10.0, -10.0,		/*   direction */      0.0, 0.0, 0.0, 0.0);		/*   conc/spread/atten (unused) */    DefineLightSource(WorkstnID, 3,	/* light source 3 */      PLIGHT_SOURCE_DIR,		/*   directional */      0.7, 0.7, 0.7,			/*   colour (dim white) */      0.0, 0.0, 0.0,			/*   position (unused) */      -10.0, -10.0, -2.0,		/*   direction */      0.0, 0.0, 0.0, 0.0);		/*   conc/spread/atten (unused) */}/****************************************************************************/DefineLightSource(WorkstnID, LightNo, LightType, R, G, B, X, Y, Z, dX, dY, dZ,  Exponent, Spread, Att1, Att2)Pint	WorkstnID;			/* workstation ID */Pint	LightNo, LightType;		/* index and type */Pfloat	R, G, B;			/* colour */Pfloat	X, Y, Z;			/* position (positional) */Pfloat	dX, dY, dZ;			/* direction (all but ambient) */Pfloat	Exponent;			/* concentration exponent (spot) */Pfloat	Spread;				/* spread angle (spot) */Pfloat	Att1, Att2;			/* attenuation factors (pos., spot) */{    Plight_source_rep	LightSource;	/* light source representation */    LightSource.type = LightType;    switch (LightType) {	case PLIGHT_SOURCE_AMB:	    SetGColr(LightSource.data.amb.colr, R, G, B);	    break;	case PLIGHT_SOURCE_DIR:	    SetGColr(LightSource.data.dir.colr, R, G, B);	    LightSource.data.dir.dir.delta_x = dX;	    LightSource.data.dir.dir.delta_y = dY;	    LightSource.data.dir.dir.delta_z = dZ;	    break;	case PLIGHT_SOURCE_POS:	    SetGColr(LightSource.data.pos.colr, R, G, B);	    LightSource.data.pos.pos.x = X;	    LightSource.data.pos.pos.y = Y;	    LightSource.data.pos.pos.z = Z;	    LightSource.data.pos.c1 = Att1;	    LightSource.data.pos.c2 = Att2;	    break;	case PLIGHT_SOURCE_SPOT:	    SetGColr(LightSource.data.spot.colr, R, G, B);	    LightSource.data.spot.pos.x = X;	    LightSource.data.spot.pos.y = Y;	    LightSource.data.spot.pos.z = Z;	    LightSource.data.spot.dir.delta_x = dX;	    LightSource.data.spot.dir.delta_y = dY;	    LightSource.data.spot.dir.delta_z = dZ;	    LightSource.data.spot.concent_exp = Exponent;	    LightSource.data.spot.c1 = Att1;	    LightSource.data.spot.c2 = Att2;	    LightSource.data.spot.spread_angle = Spread;	    break;    }    pset_light_source_rep(WorkstnID, LightNo, &LightSource);}/****************************************************************************/DefineColourRamp(WorkstnID, FirstR, FirstG, FirstB, LastR, LastG, LastB,  RampSize, CMappingIndex, WeightVector)Pint		WorkstnID;			/* workstation identifier */Pfloat		FirstR, FirstG, FirstB;		/* RGB of first colour */Pfloat		LastR, LastG, LastB;		/* RGB of last colour */Pint		RampSize;			/* size of ramp */Pint		CMappingIndex;			/* colr mapping table index */Pfloat_list	*WeightVector;			/* for colr->gray conversion */{    Pcolr_map_rep ColourMapRep;			/* c-mapping representation */    Prgb	Colours[256];			/* max needed */    Pcolrv_list	ColourList;			/* list of colours */    Pfloat	DeltaR, DeltaG, DeltaB;		/* diff: colr(i), colr(i+1) */    Pint	Error;				/* error-return variable */    Pint	I;				/* loop control variable */    DeltaR = (LastR - FirstR) / (RampSize - 1);    DeltaG = (LastG - FirstG) / (RampSize - 1);    DeltaB = (LastB - FirstB) / (RampSize - 1);    for (I = 0; I < RampSize; I++) {	Colours[I].red   = FirstR + DeltaR * I;	Colours[I].green = FirstG + DeltaG * I;	Colours[I].blue  = FirstB + DeltaB * I;    }    ColourList.colrs.colr_reps.rgb = Colours;    ColourList.num_colrs = RampSize;    ColourMapRep.method = PCOLR_MAP_METHOD_PSEUDO;    ColourMapRep.data.pseudo.model = PMODEL_RGB;    ColourMapRep.data.pseudo.weight_vector.num_floats=WeightVector->num_floats;    ColourMapRep.data.pseudo.weight_vector.floats = WeightVector->floats;    ColourMapRep.data.pseudo.colrs = ColourList;    pset_colr_map_rep(WorkstnID, CMappingIndex, &ColourMapRep);}