flatshading.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 deg 			*3.1415926535897932384/180    /* deg to rad */

main()					/* file "FlatShading.c" */
{
    Pint	WorkstnID = 1;		/* workstation identifier */
    Pint	ConnID;			/* connection identifier */
    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */
    Pint	Cube = 1, Scene = 2;	/* structure identifiers */
    Pgcolr	White;			/* for white interiors, edges */
    Pint_list	LightsOn, LightsOff;	/* for setting light source state */
    Pint	AllLights[4] = {1, 2, 3, 4};
    Pvec3	Vec;			/* for various scaling/translation */
    Pmatrix3	xform;			/* transformation 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 env: direct */
    DefineCube(Cube);
    DefineLightSources(WorkstnID);
    ppost_struct(WorkstnID, Scene, 1.0);
    /*=== define the scene =================================================*/
    popen_struct(Scene);
    pset_facet_cull_mode(PFACET_CULL_BACKFACING);
    pset_edge_flag(PEDGE_ON);
    SetGColr(White, 1.0, 1.0, 1.0);
    pset_edge_colr(&White);
    pset_int_style(PSTYLE_SOLID);
    pset_int_colr(&White);
    pset_refl_model(PREFL_MODEL_AMB_DIFF_REFL);
    LightsOn.num_ints = 4;
    LightsOn.ints = AllLights;
    LightsOff.num_ints = 0;
    pset_light_source_st(&LightsOn, &LightsOff);
    /*--- create modelling transformation ----------------------------------*/
    Vec.delta_x = 0.3, Vec.delta_y = 0.3, Vec.delta_z = 0.3;
    pscale3(&Vec, &Error, xform);
    if (Error) printf("Error", Error, " in pscale3.\n"), exit(1);
    pset_local_tran3(xform, PTYPE_REPLACE);
    protate_y(15 deg, &Error, xform);
    if (Error) printf("Error", Error, " in protate_y.\n"), exit(1);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    protate_x(15 deg, &Error, xform);
    if (Error) printf("Error", Error, " in protate_x.\n"), exit(1);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    Vec.delta_x = 0.5, Vec.delta_y = 0.5, Vec.delta_z = 0.5;
    ptranslate3(&Vec, &Error, xform);
    if (Error) printf("Error", Error, " in ptranslate3.\n"), exit(1);
    pset_local_tran3(xform, PTYPE_POSTCONCAT);
    pexec_struct(Cube);			/* execute structure */
    pclose_struct();			/* close structure */
    /*=== close up shop ====================================================*/
    pclose_ws(WorkstnID);
    pclose_phigs();
}
/****************************************************************************/
DefineCube(Cube)
Pint	Cube;
{
    static Ppoint3		TopPts[5] =
       {{-1.0,  1.0, -1.0}, {-1.0,  1.0,  1.0}, { 0.0,  1.0,  1.0},
	{ 1.0,  1.0,  0.0}, { 1.0,  1.0, -1.0}};
    static Ppoint_list3		Top = {5, TopPts};
    static Ppoint_list_list3	TopList = {1, &Top};
    static Ppoint3		BottomPts[4] =
       {{-1.0, -1.0,  1.0}, {-1.0, -1.0, -1.0}, { 1.0, -1.0, -1.0},
	{ 1.0, -1.0,  1.0}};
    static Ppoint_list3		Bottom = {4, BottomPts};
    static Ppoint_list_list3	BottomList = {1, &Bottom};
    static Ppoint3		RightPts[5] =
       {{ 1.0, -1.0, -1.0}, { 1.0,  1.0, -1.0}, { 1.0,  1.0,  0.0},
	{ 1.0,  0.0,  1.0}, { 1.0, -1.0,  1.0}};
    static Ppoint_list3		Right = {5, RightPts};
    static Ppoint_list_list3	RightList = {1, &Right};
    static Ppoint3		LeftPts[4] =
       {{-1.0, -1.0,  1.0}, {-1.0,  1.0,  1.0}, {-1.0,  1.0, -1.0},
	{-1.0, -1.0, -1.0}};
    static Ppoint_list3		Left = {4, LeftPts};
    static Ppoint_list_list3	LeftList = {1, &Left};
    static Ppoint3		FrontPts[5] =
       {{ 1.0, -1.0,  1.0}, { 1.0,  0.0,  1.0}, { 0.0,  1.0,  1.0},
	{-1.0,  1.0,  1.0}, {-1.0, -1.0,  1.0}};
    static Ppoint_list3		Front = {5, FrontPts};
    static Ppoint_list_list3	FrontList = {1, &Front};
    static Ppoint3		BackPts[4] =
       {{-1.0, -1.0, -1.0}, {-1.0,  1.0, -1.0}, { 1.0,  1.0, -1.0},
	{ 1.0, -1.0, -1.0}};
    static Ppoint_list3		Back = {4, BackPts};
    static Ppoint_list_list3	BackList = {1, &Back};
    static Ppoint3		CornerPts[3] =
       {{ 1.0,  0.0,  1.0}, { 1.0,  1.0,  0.0}, { 0.0,  1.0,  1.0}};
    static Ppoint_list3		Corner = {3, CornerPts};
    static Ppoint_list_list3	CornerList = {1, &Corner};

    popen_struct(Cube);
    pfill_area_set3(&TopList);		/* \				   */
    pfill_area_set3(&RightList);	/*  \				   */
    pfill_area_set3(&FrontList);	/*   \  pfill_area_set3 is used	   */
    pfill_area_set3(&BottomList);	/*    > instead of pfill_area3	   */
    pfill_area_set3(&LeftList);		/*   /	so edges would be visible  */
    pfill_area_set3(&BackList);		/*  /				   */
    pfill_area_set3(&CornerList);	/* /				   */
    pclose_struct();
}
/****************************************************************************/
DefineLightSources(WorkstnID)
Pint	WorkstnID;
{
    DefineLightSource(WorkstnID, 1,	/* light source 1 */
      PLIGHT_SOURCE_AMB,		/*   ambient */
      0.2, 0.2, 0.2,			/*   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_POS,		/*   positional */
      0.6, 0.0, 0.0,			/*   colour (dark red) */
      0.0, 5.0, 0.0,			/*   position */
      0.0, 0.0, 0.0,			/*   direction (unused) */
      0.0, 0.0, 1.0, 0.0);		/*   conc/spread (unused), atten */
    DefineLightSource(WorkstnID, 3,	/* light source 3 */
      PLIGHT_SOURCE_DIR,		/*   directional */
      0.0, 0.0, 0.7,			/*   colour (dark blue) */
      0.0, 0.0, 0.0,			/*   position (unused) */
      0.0, 0.0, -5.0,			/*   direction */
      0.0, 0.0, 0.0, 0.0);		/*   conc/spread/atten (unused) */
    DefineLightSource(WorkstnID, 4,	/* light source 4 */
      PLIGHT_SOURCE_POS,		/*   positional */
      0.0, 0.5, 0.0,			/*   colour (dark green) */
      -1.5, 0.0, 0.0,			/*   position */
      0.0, 0.0, 0.0,			/*   direction (unused) */
      0.0, 0.0, 1.0, 0.0);		/*   conc/spread (unused), atten */
}
/****************************************************************************/
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);
}