/*
 *  FILE: dualpf.c
 *  Support routines for converting a single-playfield Intuition screen
 *  into a dual-playfield screen and back.
 *
 *  Public Domain, but keep my name in it as the original author.
 *  31-Aug-88	Jan Sven Trabandt   first release version
 */


#include "gimmelib/gimmefuncs.h"


short makeDualPlayfield( screen, ri, reldepth )
    struct Screen   *screen;
    struct RasInfo  *ri;
    SHORT	    reldepth;
{
    SHORT   depth;

#ifdef GIMME_WIMPY
    if( !screen ) {
	return( -1 );
    }
#endif
    if( (screen->ViewPort.Modes & DUALPF)
	|| reldepth < -1 || reldepth > 0 || screen->BitMap.Depth > 3 ) {
	return( -1 );
    }
    depth = screen->BitMap.Depth + reldepth;
    if( depth > 3 ) {
	return( -1 );
    }
    ri->BitMap = gimmeBitMap( depth, screen->Width, screen->Height );
    if( !ri->BitMap ) {
	return( -1 );
    }
    ri->Next = NULL;
    ri->RxOffset = 0;
    ri->RyOffset = 0;
    Forbid();
    screen->ViewPort.RasInfo->Next = ri;
    screen->ViewPort.Modes |= DUALPF;
    Permit();
    MakeScreen( screen );
    RethinkDisplay();
    return( 0 );
} /* makeDualPlayfield */


short unmakeDualPlayfield( screen )
    struct Screen   *screen;
{
    struct RasInfo  *ri;
    struct BitMap   *bm;

#ifdef GIMME_WIMPY
    if( !screen ) {
	return( -1 );
    }
#endif
    if( !(screen->ViewPort.Modes & DUALPF) ) {
	return( -1 );
    }
    Forbid();
    ri = screen->ViewPort.RasInfo->Next;
    bm = ri->BitMap;
    ri->BitMap = NULL;
    screen->ViewPort.RasInfo->Next = NULL;
    screen->ViewPort.Modes &= ~(DUALPF | PFBA);
    Permit();
    MakeScreen( screen );
    RethinkDisplay();
    if( bm ) {
	getRidOfBitMap( bm );
    }
    return( 0 );
} /* unmakeDualPlayfield */