/* rotate-mb.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"
#include "mbx.h"

static Display			*dpy;
static Window			window;
static PEXRenderer		renderer;
static Multibuffer		buffers[2], cur_buf;

/* The triangle's coordinates. */
static PEXCoord2D points[] = {{.4,.5},{.6,.5},{.5,.9}};

static void
redraw( angle )
    double		angle;
{
    PEXColor		color;
    PEXMatrix3x3	xform;
    static PEXCoord2D	center = {0.5, 0.5};
    static PEXVector2D	shift = {0,0}, scale = {1,1};
    
    /* Redraw into the off-screen buffer. */
    PEXBeginRendering( dpy, cur_buf, renderer ); {
	/* Build the transform for the new angle. */
	PEXBuildTransform2D( &center, &shift, angle, &scale, xform );
	PEXSetLocalTransform2D( dpy, renderer, PEXOCRender,
			        PEXReplace, xform );
	
	/* Create the primitive. */
	PEXSetInteriorStyle( dpy, renderer, PEXOCRender,
			    PEXInteriorStyleSolid );
	SET_COLOR( 1, 0, 0, color ); /* red */
	PEXSetSurfaceColor( dpy, renderer, PEXOCRender,
			    PEXColorTypeRGB, &color );
	PEXFillArea2D( dpy, renderer, PEXOCRender, PEXShapeConvex,
		       True, 3, points );
    }
    PEXEndRendering( dpy, renderer, True );

    /* Display the buffer. */
    XmbufDisplayBuffers( dpy, 1, &cur_buf, 0, 0 );
    XFlush( dpy );
    
    /* Make the undisplayed buffer the drawing buffer. */
    cur_buf = (cur_buf == buffers[0] ? buffers[1] : buffers[0]);
}

#define WIN_GEOM	"500x500+50+50"

main( argc, argv )
    int		argc;
    char	*argv[];
{
    XEvent			event;
    XVisualInfo			vis_info;
    XColor			bkgd_color;
    XStandardColormap		cmap_info;
    PEXColorApproxEntry		capx_info;
    PEXRendererAttributes	rattrs;
    PEXExtensionInfo		*pexinfo;
    int				done = 0;
    double			angle = 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 );
    
    /* Set up the PEX renderer. */
    if ( IMMED_MODE_SPT( pexinfo ) ) {
	renderer = ora_setup_renderer( dpy, window, &capx_info,
				       &rattrs );
    } else {
	fprintf( stderr, "No immediate mode.\n" );
	exit(1);
    }
    
    /* Create the MBX buffers. */
    if ( ora_create_mbx_buffers( dpy, window, 2, buffers ) )
	/* Set the current buffer to buffer 1. */
	cur_buf = buffers[1];
    else	
	exit( 1 );
    
    /* 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( angle );
	    break;
	case ButtonPress:
	    switch( event.xbutton.button ) {
	    case Button1:
		/* Rotate. */
		for ( angle = 2*M_PI - M_PI/60;
		      angle > 0;
		      angle -= M_PI/60 ) {
			redraw( angle );
		}		    
		
		/* Reset to initial position. */
		redraw( angle = 0 );
		break;
	    default:
		done = 1;
		break;
	    }
	    break;
	}
    }

    XmbufDestroyBuffers( dpy, window );
    XCloseDisplay( dpy );
    return 0;
}