DirectX Media SDK DirectAnimation Tutorial

The 3-D animation

the length of the first segment of the animation in seconds

NumberBvr period = toBvr(6);

time-varying angle, does a complete cycle per period

NumberBvr aniAngle = mul(localTime, mul(toBvr(2),

div(toBvr(Math.PI), period)));

A translation between front and back Z limits used for travel of the center of the geometric image. The limits are related to the extent of the picture.

NumberBvr distOfTravel = mul(toBvr(20), maxHalfExtent);
Transform3Bvr trans = translate(toBvr(0), toBvr(0),

mul(neg(distOfTravel), sin(aniAngle)));

a rotation with rate "aniAngle" around a time varying axis

Transform3Bvr rot = rotate(vector3(sin(aniAngle), cos(aniAngle),

div(sin(aniAngle), toBvr(2))), aniAngle);

tumbling in 3-D animation, performs a complete cycle in one "period":

Transform3Bvr rot1 = compose(trans, rot);

open page animation, opens in one quarter of "period":

Transform3Bvr rot2 =

compose(translate(neg(xUpperRight), toBvr(0), toBvr(0)),

compose(rotate(yVector3, neg(aniAngle)),

translate(xUpperRight, toBvr(0), toBvr(0))));

close page animation, closes in one quarter of "period":

Transform3Bvr rot3 =

compose(translate(neg(xUpperRight), toBvr(0), toBvr(0)),

the -PI/2 is to pick up from where the page open animation left of

compose(rotate(yVector3, add(div(neg(toBvr(Math.PI)), toBvr(2)), aniAngle)),

translate(xUpperRight, toBvr(0), toBvr(0))));

the cyclic animation of the geoimage: - tumbling in 3-D in one "period" - open page in quarter of "period" - close page in quarter of "period"

NumberBvr quarterPeriod = div(period, toBvr(4));
Transform3Bvr loopingTrans = Transform3Bvr.newUninitBvr();
loopingTrans.init(until(rot1, timer(period),

until(rot2, timer(quarterPeriod),

until(rot3, timer(quarterPeriod), loopingTrans))));

GeometryBvr loopingGeoImage = geoImage.transform(loopingTrans);