flatsmooth.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 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	RampSize	50		/* size of colour ramps */
#define	Black		0.0, 0.0, 0.0	/* RGB for black */
#define	White		1.0, 1.0, 1.0	/* RGB for white */
#define	Blue		0.0, 0.0, 1.0	/* RGB for blue */
#define	Green		0.0, 1.0, 0.0	/* RGB for green */
#define	Yellow		1.0, 1.0, 0.0	/* RGB for yellow */
#define	Red		1.0, 0.0, 0.0	/* RGB for red */

main()					/* file "FlatSmooth.c" */
{
    Pint	WorkstnID = 1;		/* workstation identifier */
    Pint	ConnID;			/* connection identifier */
    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */
    Pint	FillArea = 1, Scene = 2;/* structure IDs chosen by user */
    Pgcolr	Colour;			/* for color table value */
    Pmatrix3	Matrix;			/* for transformation matrices */
    static Pfloat WeightVecVals[3] = 	/* for determining colour index */
		{1.0, 0.0, 0.0};	/* arbitrarily use red */
    static Pfloat_list	WeightVector = {3, WeightVecVals};
    static char	String[2][15] = 	/* for textual labels */
		{"Flat Shading", "Smooth Shading"};
    static Pvec	NullVec = {0.0, 0.0};	/* for panno_text_rel */
    Ppoint	Loc;			/* location of annotation text */
    Pvec3	Vec;			/* for translation */
    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 color env: direct */
    pescape_u240(WorkstnID, 1);		/* turn off dithering (cell=1x1) */
    /*--- define the filled areas ------------------------------------------*/
    popen_struct(FillArea);
    CreatePrimitives();			/* make filled areas */
    pclose_struct();
    /*--- define whole scene -----------------------------------------------*/
    popen_struct(Scene);
    DefineColourRamps(WorkstnID, 1, &WeightVector);
    pset_colr_map_ind(1);
    pset_text_font(-4);
    /*--- white text, which is in second entry of color list ---------------*/
    SetGColr(Colour, 2.0 / (3 * RampSize + 2), 0.0, 0.0);
    pset_text_colr(&Colour);
    pset_anno_char_ht(0.05);
    Loc.x = 0.1, Loc.y = 0.9;
    panno_text_rel(&Loc, &NullVec, String[0]);
    Loc.x = 0.1, Loc.y = 0.4;
    panno_text_rel(&Loc, &NullVec, String[1]);
    pset_int_style(PSTYLE_SOLID);
    pset_refl_model(PREFL_MODEL_NO_REFL);
    pset_int_shad_method(PINT_SHAD_METHOD_NONE);
    pexec_struct(FillArea);
    Vec.delta_x = 0.0, Vec.delta_y = -0.5, Vec.delta_z = 0.0;
    ptranslate3(&Vec, &Error, Matrix);
    pset_local_tran3(Matrix, PTYPE_REPLACE);
    pset_int_shad_method(PINT_SHAD_METHOD_COLR);
    pexec_struct(FillArea);
    pclose_struct();
    /*--- close up shop ----------------------------------------------------*/
    ppost_struct(WorkstnID, Scene, 1.0);
    pclose_ws(WorkstnID);
    pclose_phigs();
}
/****************************************************************************/
CreatePrimitives()
{
    Ppoint3	Points[4];		/* XYZ data */
    Pfacet	Facets;			/* facet data */
    Pvertex3_set VertexSet;		/* vertex data */
    Pvertex3_list VertexList[1];	/* array of lists for set */
    Ppoint3	Vertices[4];		/* vertices' XYZ data */
    Prgb	FacetColour;		/* direct RGB color */
    Prgb	VertexColour[4];	/* direct RGB color */
    Pfloat	Colour, dColour;	/* value to increment Colour */
    Pint	I, J;			/* loop control variables */

    Facets.num_data_per_facet = 0;
    Facets.facet_norm = NULL;
    Facets.facet_data = NULL;
    Facets.facet_colrv = (void *) &FacetColour;
    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 = VertexColour;
    VertexList[0].vertex_norms = NULL;
    VertexList[0].vertex_data = NULL;

    Colour = 3.0/(3 * RampSize + 2);
    dColour = (3 * RampSize)/(3.0 * RampSize + 2)/9;
    for (I = 0; I < 10; I++) {
	for (J = 0; J < 4; J++) {
	    Vertices[J].x = (I + 1 + (J == 1 || J == 2)) / 12.0;
	    Vertices[J].y = 0.55 + 0.3 * (J >= 2);
	    Vertices[J].z = 0.0;
	}
	FacetColour.red   = Colour;
	FacetColour.green = FacetColour.blue  = 0.0;
	VertexColour[0].red   =  Colour;
	VertexColour[0].green =  VertexColour[0].blue = 0.0;
	VertexColour[1].red   =  Colour + dColour;
	VertexColour[1].green =  VertexColour[1].blue = 0.0;
	VertexColour[2].red   =  Colour + dColour;
	VertexColour[2].green =  VertexColour[2].blue = 0.0;
	VertexColour[3].red   =  Colour;
	VertexColour[3].green =  VertexColour[3].blue = 0.0;
	pfill_area_set3_data(PCOLR_RGB, &Facets, NULL, &VertexSet);
	Colour += dColour;
    }
}
/****************************************************************************/
DefineColourRamps(WorkstnID, CMappingIndex, WeightVector)
Pint		WorkstnID;		/* workstation identifier */
Pint		CMappingIndex;		/* colour mapping table index */
Pfloat_list	*WeightVector;		/* for colour->gray conversion */
{
    Pcolr_map_rep	ColourMapRep;		/* c-mapping representation */
    Prgb		Colours[256];		/* max needed */
    Pcolrv_list		ColourList;		/* list of colours */
    Pint		Error;			/* error-return variable */
    Pint		Idx;			/* ramp-starting locations */

    Idx = 0;				/* start location of 2-entry ramp */
    DefineColourRamp(Black, White, Idx, 2, Colours);
    Idx = Idx + 2;			/* increment by size of last ramp */
    DefineColourRamp(Blue, Green, Idx, RampSize, Colours);
    Idx = Idx + RampSize;		/* increment by size of last ramp */
    DefineColourRamp(Green, Yellow, Idx, RampSize + 1, Colours);
    Idx = Idx + RampSize;		/* increment by size of last ramp */
    DefineColourRamp(Yellow, Red, Idx, RampSize, Colours);
    ColourList.num_colrs = 2 + 3 * RampSize;	/* b/w ramp + 3 colr ramps */
    ColourList.colrs.colr_reps.rgb = Colours;
    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);
}
/****************************************************************************/
DefineColourRamp(R1, G1, B1, R2, G2, B2, Idx, RampSz, Colours)
Pfloat	R1, G1, B1, R2, G2, B2;		/* extremes of ramp */
Pint	Idx;				/* location in Colours array */
Pint	RampSz;				/* "local ramp size" */
Prgb	Colours[];			/* array being filled */
{
    Pfloat	dR, dG, dB;		/* diff. between colr(i), colr(i+1) */
    Pint	I;			/* loop control variable */

    dR = (R2 - R1) / (RampSz - 1);
    dG = (G2 - G1) / (RampSz - 1);
    dB = (B2 - B1) / (RampSz - 1);
    for (I = 0; I < RampSz; I++) {
	Colours[Idx + I].red   = R1 + dR * I;
	Colours[Idx + I].green = G1 + dG * I;
	Colours[Idx + I].blue  = B1 + dB * I;
    }
}