/* view-cyl.c 1.1 */
/*
    Copyright 1992, 1993 O'Reilly and Associates, Inc.  Permission to
    use, copy, and modify this program is hereby granted, as long as
    this copyright notice appears in each copy of the program source
    code.
*/

#include "book_utils.h"

/* Globals. */
static PEXStructure	model;   
static Display		*dpy;
static Window		window;
static PEXRenderer	renderer;
static unsigned int	view_num = 1;

/* Constants */
#define NUM_SEGS	32
#define CYL_RADIUS	1.0
#define CYL_HEIGHT	1.0
#define AXIS_LENGTH	0.3

static void
initialize_view( view_table )
    PEXLookupTable	view_table;
{
    PEXCoord		view_ref_pt, prp;
    PEXVector		view_up_vec, view_plane_normal;
    PEXCoord2D		view_window[2];
    double		view_plane, front_plane, back_plane;
    PEXNPCSubVolume	viewport;
    PEXViewEntry	view;
    int			err, perspective;

    /* Compute the view orientation transform. */
    view_ref_pt.x = 0;
    view_ref_pt.y = 0;
    view_ref_pt.z = 0;
    
    view_up_vec.x = 0;
    view_up_vec.y = 1;
    view_up_vec.z = 0;
    
    view_plane_normal.x = 1;
    view_plane_normal.y = 1;
    view_plane_normal.z = 1;
    err = PEXViewOrientationMatrix( &view_ref_pt,
				    &view_plane_normal,
				    &view_up_vec,
				    view.orientation );
    
    /* The view mapping parameters. */
    perspective = False;
    view_plane = 0;
    prp.x = 0; prp.y = 0; prp.z = 10;
    view_window[0].x = -1.5; view_window[1].x = 1.5;
    view_window[0].y = -1.5; view_window[1].y = 1.5;
    back_plane       = -1.5; front_plane      = 1.5;
    viewport.min.x = 0; viewport.max.x = 1;
    viewport.min.y = 0; viewport.max.y = 1;
    viewport.min.z = 0; viewport.max.z = 1;
    
    /* Compute the view mapping transform. */
    err = PEXViewMappingMatrix( view_window, &viewport, perspective,
			        &prp, view_plane, back_plane,
			        front_plane, view.mapping );
    
    /* The view clipping parameters. */
    view.clip_flags = PEXClippingAll;
    view.clip_limits = viewport;
    
    /* Set the view. */
    PEXSetTableEntries( dpy, view_table, view_num, 1,
		        PEXLUTView, (PEXPointer) &view );
}

void
create_model()
{
    PEXCoord		vertices[4*(NUM_SEGS+1)];
    PEXCoord		*top, *bot, *sides;
    PEXListOfVertex	lines[NUM_SEGS+3];
    PEXCoord		center;
    PEXStructure	axes, cylinder;
    PEXColor		color;
    double		angle, delta;
    int			i;

    /* Create the axes structure. */
    center.x = center.y = center.z = 0;
    axes = ora_build_axes_struct( dpy, &center, AXIS_LENGTH );
    
    
    /* Create the cylinder structure. */
    cylinder = PEXCreateStructure( dpy );
    
    /* Build the cylinder, a polyline set with data primitive. */
    top = vertices;
    lines[0].count = NUM_SEGS + 1;
    lines[0].vertices.no_data = top;
    
    bot = top + NUM_SEGS + 1;
    lines[1].count = NUM_SEGS + 1;
    lines[1].vertices.no_data = bot;
    
    sides = bot + NUM_SEGS + 1;
    
    /* Calculate the vertices for the polylines. */
    angle = 0;
    delta = (2 * M_PI) / NUM_SEGS;
    for ( i = 0; i < NUM_SEGS + 1; i++, angle += delta ) {
	/* The top circle. */
	top[i].x = center.x + CYL_RADIUS * cos( angle );
	top[i].y = center.y + 0.5 * CYL_HEIGHT;
	top[i].z = center.z + CYL_RADIUS * sin( angle );
	
	/* The bottom circle. */
	bot[i].x = top[i].x;
	bot[i].y = center.y - 0.5 * CYL_HEIGHT;
	bot[i].z = top[i].z;

	/* The side polylines. */
	if ( i <= NUM_SEGS ) {
	    lines[i+2].count = 2;
	    lines[i+2].vertices.no_data = sides;
	    sides[0] = top[i];
	    sides[1] = bot[i];
	
	    /* Move the vertex pointer two vertices forward. */
	    sides += 2;
	}
    }
    
    /* Create the cylinder. */
    SET_COLOR( 1, 1, 1, color );
    PEXSetLineColor( dpy, cylinder, PEXOCStore,
		     PEXColorTypeRGB, &color );
    PEXPolylineSetWithData( dpy, cylinder, PEXOCStore, PEXGANone,
			    PEXColorTypeRGB, NUM_SEGS+2, lines );

    
    /* Create the top-level structure. */
    model = PEXCreateStructure( dpy );

    /* Make all following primitives use the selected view. */
    PEXSetViewIndex( dpy, model, PEXOCStore, view_num );
    
    /* Execute the structures containing the primitives. */
    PEXExecuteStructure( dpy, model, PEXOCStore, cylinder );
    PEXExecuteStructure( dpy, model, PEXOCStore, axes );
}

static void
redraw()
{
    XClearWindow( dpy, window );
    PEXRenderNetwork( dpy, window, renderer, model );
    XFlush( dpy );
}

#define WIN_GEOM	"500x500+50+50"

main( argc, argv )
    int		argc;
    char	*argv[];
{
    XEvent			event;
    XVisualInfo			vis_info;
    XStandardColormap		cmap_info;
    PEXColorApproxEntry		capx_info;
    PEXRendererAttributes	rattrs;
    PEXExtensionInfo		*pexinfo;
    XColor			bkgd_color;
    int				done = 0;
    
    /* Open a display and initialize PEX. */
    dpy = ora_init_pex( argv, &pexinfo );
    if ( !dpy ) exit(1);
    
    /* Determine the best visual to use. */
    ora_find_best_visual( dpy, &vis_info );

    /* Get a standard colormap for the visual. */
    if ( !ora_get_standard_colormap( dpy, &vis_info, &cmap_info ) ) {
	fprintf ( stderr, "Cannot find a standard colormap\n" );
	exit(1);
    }
    ora_set_stdcmap_approx( &vis_info, &cmap_info, &capx_info );

    /* Create the window. */
    bkgd_color.red = bkgd_color.green = bkgd_color.blue = 0;
    bkgd_color.flags = DoRed | DoGreen | DoBlue;
    window = ora_create_window( dpy, &vis_info, &cmap_info,
			        WIN_GEOM, &bkgd_color );
    
    /* Create the model and set up the PEX renderer. */
    if ( STRUCTURE_SPT( pexinfo ) ) {
	create_model();
	renderer = ora_setup_renderer( dpy, window, &capx_info,
				       &rattrs );
    } else {
	fprintf( stderr, "Structures not supported.\n" );
	exit(1);
    }
    
    /* Initialize the view. */
    initialize_view( rattrs.view_table );
    
    /* Read and respond to X events. */
    XSelectInput( dpy, window, ButtonPressMask |  ExposureMask );
    while ( !done ) {
	XNextEvent( dpy, &event );
	switch ( event.type ) {
	case ButtonPress:
	    done = 1;
	    break;

	case Expose:
	    /* Flush remaining Expose events, then redraw. */
	    while ( XCheckTypedWindowEvent( dpy, window,
					    Expose, &event ) )
		; /* empty statement */
	    redraw();
	    break;
	}
    }
    
    XCloseDisplay( dpy );
    return 0;
}