/* quadmesh.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"

#define WIN_GEOM	"500x500+50+50"

/* Structure ID */
static PEXStructure	struct_id;

/* Miscellaneous constants we use. */
#define NUM_X_INTERVALS		20
#define NUM_Z_INTERVALS		20
#define NUM_X_POINTS		(NUM_X_INTERVALS + 1)
#define NUM_Z_POINTS		(NUM_Z_INTERVALS + 1)
#define X0			0.5
#define Z0			0.5

static void
create_structure( dpy )
    Display	*dpy;
{
    PEXColor		color;
    PEXCoord		vertices[NUM_X_POINTS * NUM_Z_POINTS];
    PEXCoord		origin;
    PEXArrayOfVertex	verts;
    PEXStructure	axes;
    PEXArrayOfFacetData	dummy;
    unsigned int	facet_data_flag, vertex_data_flag;
    int			i, j, index;
    double		x, dx, z, dz;
    
    /* Generate the points for the surface. */
    dx = 1.0 / (NUM_X_INTERVALS);
    dz = 1.0 / (NUM_Z_INTERVALS);
    for ( j = 0, z = 0.0; j < NUM_Z_POINTS; j++, z += dz ) {
	for ( i = 0, x = 0.0; i < NUM_X_POINTS; i++, x += dx ) {
	    index = j * NUM_X_POINTS + i;
	    vertices[index].x = x;
	    vertices[index].y =
		(x - X0) * (x - X0) + (z - Z0) * (z - Z0);
	    vertices[index].z = z;
	}
    }
    
    /* Create the structure. */
    struct_id = PEXCreateStructure( dpy );
    
    /* Set the view index. */
    PEXSetViewIndex( dpy, struct_id, PEXOCStore, 1 );
    
    /* Build the axes. */
    origin.x = origin.y = origin.z = 0;
    axes = ora_build_axes_struct( dpy, &origin, 0.6 );
    PEXExecuteStructure( dpy, struct_id, PEXOCStore, axes );
    
    /* Distinguish between front and back faces. */
    PEXSetFacetDistinguishFlag( dpy, struct_id, PEXOCStore, True );
    
    /* Set the interior style and color for front faces. */
    PEXSetInteriorStyle( dpy, struct_id, PEXOCStore,
			 PEXInteriorStyleHollow );
    SET_COLOR( 1, 1, 1, color ); /* white */
    PEXSetSurfaceColor( dpy, struct_id, PEXOCStore,
		        PEXColorTypeRGB, &color );

    /* Set the back interior style and color for back faces. */
    PEXSetBFInteriorStyle( dpy, struct_id, PEXOCStore,
			   PEXInteriorStyleSolid );
    PEXSetBFSurfaceColor( dpy, struct_id, PEXOCStore,
			  PEXColorTypeRGB, &color );
    
    /* Create the quadrilateral mesh. */
    facet_data_flag = PEXGANone;
    vertex_data_flag = PEXGANone;
    verts.no_data = vertices;
    PEXQuadrilateralMesh( dpy, struct_id, PEXOCStore, PEXShapeConvex,
			  facet_data_flag, vertex_data_flag,
			  PEXColorTypeRGB, dummy,
			  NUM_Z_POINTS, NUM_X_POINTS, verts );
}

static void
redraw( dpy, window, renderer )
    Display	*dpy;
    Window	window;
    PEXRenderer	renderer;
{
    XClearWindow( dpy, window );
    PEXRenderNetwork( dpy, window, renderer, struct_id );
    XFlush( dpy );
}

extern void set_view();

main( argc, argv )
    int		argc;
    char	*argv[];
{
    Display			*dpy;
    Window			window;
    XEvent			event;
    XVisualInfo			vis_info;
    XColor			bkgd_color;
    XStandardColormap		cmap_info;
    PEXColorApproxEntry		capx_info;
    PEXRenderer			renderer;
    PEXRendererAttributes	rattrs;
    PEXExtensionInfo		*pexinfo;
    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, giving it a gray background. */
    bkgd_color.red = bkgd_color.green = bkgd_color.blue = 0x5555;
    bkgd_color.flags = DoRed | DoGreen | DoBlue;
    window = ora_create_window( dpy, &vis_info, &cmap_info, WIN_GEOM,
			        &bkgd_color );
    
    /* Create the structure and Set up the PEX renderer. */
    if ( STRUCTURE_SPT( pexinfo ) ) {
	create_structure( dpy );
	renderer = ora_setup_renderer( dpy, window, &capx_info,
				       &rattrs );
    } else {
	fprintf( stderr, "Structures not supported.\n" );
	exit(1);
    }
    
    set_view( dpy, rattrs.view_table );
    
    /* Read and respond to X events. */
    XSelectInput( dpy, window, ExposureMask | ButtonPressMask );
    while ( !done ) {
	XNextEvent( dpy, &event );
	switch ( event.type ) {
	case Expose:
	    /* Flush remaining Expose events, then redraw. */
	    while ( XCheckTypedWindowEvent( dpy, window,
					    Expose, &event ) )
		; /* empty statement */
	    redraw( dpy, window, renderer );
	    break;
	case ButtonPress:
	    done = 1;
	    break;
	}
    }

    XCloseDisplay( dpy );
    return 0;
}

static void
set_view( dpy, view_table )
    Display		*dpy;
    PEXLookupTable	view_table;
{
    PEXViewEntry	view;
    PEXCoord2D		window[2];
    double		view_plane, front_plane, back_plane;
    PEXCoord		prp;
    PEXNPCSubVolume	viewport;

    /* The view orientation parameters. */
    static PEXCoord	view_ref_pt = {0.5, 0.5, 0.5};
    static PEXVector	view_plane_normal = {-0.5, 0.5, 1};
    static PEXVector	view_up_vec = {0,1,0};

    /* Compute the view orientation transform. */
    (void)PEXViewOrientationMatrix( &view_ref_pt, &view_plane_normal,
				    &view_up_vec, view.orientation );
    
    /* The view mapping parameters. */
    prp.x = 1; prp.y = 0.5; prp.z = 10;
    window[0].x = -0.8; window[1].x = 0.8;
    window[0].y = -0.9; window[1].y = 0.7;
    front_plane = 5; view_plane = 0; back_plane = -1;
    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. */
    (void)PEXViewMappingMatrix( window, &viewport, True, &prp,
			        view_plane, back_plane, front_plane,
			        view.mapping );
    
    /* The view clipping parameters. */
    view.clip_flags = PEXClippingAll;
    view.clip_limits = viewport;
    
    /* Set view 1. */
    PEXSetTableEntries( dpy, view_table, 1, 1, PEXLUTView,
		       (PEXPointer) &view );
}