Learning Maya 3/Learning_Maya_3.iso/docs/mel_scripts/includes/subSurface.mel

Text File | 2000-05-17 | 5.1 KB | 227 lines

// Copyright (C) 1997-2000 Alias|Wavefront,
// a division of Silicon Graphics Limited.
//
// The information in this file is provided for the exclusive use of the
// licensees of Alias|Wavefront.  Such users have the right to use, modify,
// and incorporate this code into other products for purposes authorized
// by the Alias|Wavefront license agreement, without fee.
//
// ALIAS|WAVEFRONT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
// INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
// EVENT SHALL ALIAS|WAVEFRONT BE LIABLE FOR ANY SPECIAL, INDIRECT OR
// CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
// DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
// TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
//
//
//    Description :
//        To extract a bounded portion on a NURBS surface defined
//        by four selected isoparams on the surface.
//
//    Usage :
//        Select 4 isoparams which enclose a region on a NURBS surface.
//        execute the script "subSurface" :
//        return the name of the nurbs surface extracted.

proc float[] minMaxSrfRange( string $srf )
//
//
//
{
    float $range[] ;
    string $attr = $srf + ".mnu" ;
    $range[0] = `getAttr $attr` ;
    $attr = $srf + ".mnv" ;
    $range[1] = `getAttr $attr` ;
    $attr = $srf + ".mxu" ;
    $range[2] = `getAttr $attr` ;
    $attr = $srf + ".mxv" ;
    $range[3] = `getAttr $attr` ;
    return $range ;
}

proc string extractSubSurface(
    string $srf,
    float $umin,
    float $vmin,
    float $umax,
    float $vmax )
//
//    Description :
//
{
    string $extract = "" ;
    //
    // detach surface  along umin, umax
    //
    string $diru = " -d 1 " ;
    string $resultsu[] ;
    string $cmd = "detachSurface " ;
    $cmd += " -ch 0 " ;
    $cmd += " -rpo 0 " ;
    $cmd += $diru ;
    $cmd += " -p " ;
    $cmd += $umin ;
    $cmd += " -p " ;
    $cmd += $umax ;
    $cmd += " " ;

    $cmd += $srf  ;
    $resultsu = eval($cmd) ;
    if( size($resultsu) == 0 ) return $extract ;

    // get the piece we really want.
    //
    int $found = -1 ;
    int $n = size($resultsu) ;
    float $midu = 0.5 * ( $umin + $umax ) ;
    float $minu, $minv ;
    float $maxu, $maxv ;
    for( $i = 0 ; $i < $n ; $i++ ) {
        float $rangeu[] ;
        $rangeu = minMaxSrfRange( $resultsu[$i] ) ;
        if( $midu <= $rangeu[2] && $midu >= $rangeu[0] ) {
            $found = $i;
            break ;
        }
    }
    if( $found == -1  )  {
        print("failed in detach along u...\n") ;
        delete $resultsu ;
        return $extract ;
    }

    // cut the found surface in v direction.
    //
    string $dirv = " -d 0 " ;
    $cmd = "detachSurface " ;
    $cmd += " -ch 0 " ;
    $cmd += " -rpo 0 " ;
    $cmd += $dirv ;
    $cmd += " -p " ;
    $cmd += $vmin ;
    $cmd += " -p " ;
    $cmd += $vmax ;
    string $ssrf = $resultsu[$found] ;
    $cmd += " " ;
    $cmd += $ssrf ;
    string $resultsv[] = eval($cmd) ;
    if( size($resultsv) == 0 ) {
        delete $resultsu ;
        return $extract ;
    }
    int $n = size($resultsv) ;
    float $midv = 0.5 * ( $vmin + $vmax ) ;
    for( $i = 0 ; $i < $n ; $i++ ) {
        float $rangev[] ;
        $rangev = minMaxSrfRange( $resultsv[$i] ) ;
        if( $midv <= $rangev[3] && $midv >= $rangev[1] ) {
            $found = $i;
            break ;
        }
    }

    delete $resultsu ;
    if( $found == -1  )  {
        print("failed in detach along v...\n") ;
        delete $resultsv ;
        return $extract ;
    }

    $extract = $resultsv[$found] ;
    for( $i = 0 ; $i < $n ; $i++ ) {
        if( $i != $found ) delete $resultsv[$i] ;
    }
    return $extract ;
}

global proc string subSurface()
//
// Description :
//        To extract only the enclosed portion of
//        the surface defined by the four selected
//        isoparms on the surface.
//
//
{

    // get the surface from the select list.
    //
    global int $gSelectIsoparmsBit;

    string $slist[] = `ls -sl` ;
    if( size($slist) == 0 ) {
        error "select a nurbs surface.";
        return "" ;
    }

    string $srf[] ;
    $srf = `filterExpand -ex true -sm $gSelectIsoparmsBit $slist` ;
    if( size($srf) != 4 ) {
        error "select bounded NURBS surface region defined by four isoparms.";
        return "" ;
    }

    // get the surface. and the region (min,max) in
    // (u,v).
    //
    int $i ;
    float $uvals[] ;
    float $vvals[] ;
    float $minu, $minv ;
    float $maxu, $maxv ;
    int $uindex = 0 ;
    int $vindex = 0 ;

    for( $i = 0 ; $i < 4 ; $i++ ) {
        string $foundUStr = `match "\\.u\\[" $srf[$i]`;
        string $foundVStr = `match "\\.v\\[" $srf[$i]`;
        int $foundU = 0 ;
        if(size($foundUStr) > 0 ) $foundU = 1 ;
        int $foundV = 0 ;
        if(size($foundVStr) > 0 ) $foundV = 1 ;
        if( !$foundU && !$foundV ) continue ;

        string $buffer[] ;
        string $token = "[" ;
        tokenize($srf[$i], "[", $buffer);

        // get the parameter value.
        //
        string $b[] ;
        $token = "]" ;
        tokenize( $buffer[1], $token, $b) ;

        if( $foundU ) {
            $uvals[$uindex] = $b[0] ;
            $uindex++ ;
        } else if( $foundV ) {
            $vvals[$vindex] = $b[0] ;
            $vindex++ ;
        }
    }

    string $buffer[] ;
    tokenize($srf[0], ".", $buffer);
    string $surface = $buffer[0];

    $umin = $uvals[0] ;
    $umax = $uvals[1] ;
    if( $uvals[0] > $uvals[1] ) {
        $umin = $uvals[1] ;
        $umax = $uvals[0] ;
    }

    $vmin = $vvals[0] ;
    $vmax = $vvals[1] ;
    if( $vvals[0] > $vvals[1] ) {
        $vmin = $vvals[1] ;
        $vmax = $vvals[0] ;
    }

    string $subSrf = extractSubSurface($surface,$umin,$vmin,$umax,$vmax);
    select -r $subSrf ;
    return $subSrf ;
}