From http://www.jwz.org/xscreensaver/xscreensaver-5.27.tar.gz

[xscreensaver] / hacks / shadebobs.c

diff --git a/hacks/shadebobs.c b/hacks/shadebobs.c
index 64fa82c9772d7e28b3ba7a87d3f74e4fd00fd6e1..d1361dd3aa4f23ed8d460cb3d65f73e7efe9e22d 100644 (file)
--- a/hacks/shadebobs.c
+++ b/hacks/shadebobs.c
@@ -147,8 +147,11 @@ static void MoveShadeBob( struct state *st, SShadeBob *pShadeBob )
        pShadeBob->nAngle          += pShadeBob->nAngleInc;
        pShadeBob->nAngleDelta -= pShadeBob->nAngleInc;
 
-       if( pShadeBob->nAngle >= st->iDegreeCount )     pShadeBob->nAngle -= st->iDegreeCount;
-       else if( pShadeBob->nAngle < 0 )                pShadeBob->nAngle += st->iDegreeCount;
+       /* Since it can happen that nAngle < 0 and nAngle + iDegreeCount >= iDegreeCount
+          on floating point, we set some marginal value.
+       */
+       if( pShadeBob->nAngle + 0.5 >= st->iDegreeCount )       pShadeBob->nAngle -= st->iDegreeCount;
+       else if( pShadeBob->nAngle < -0.5 )             pShadeBob->nAngle += st->iDegreeCount;
        
        if( ( pShadeBob->nAngleInc>0.0F  && pShadeBob->nAngleDelta<pShadeBob->nAngleInc ) ||
            ( pShadeBob->nAngleInc<=0.0F && pShadeBob->nAngleDelta>pShadeBob->nAngleInc ) )