private void drawCurve(ICurve3D curve, int color, Vector3 position) {
SimpleMaterial lineMaterial = new SimpleMaterial();
lineMaterial.setUseSingleColor(true);
Stack<Vector3> points = new Stack<Vector3>();
for (int i = 0; i <= NUM_POINTS; i++) {
Vector3 pos = curve.calculatePoint((float) i / (float) NUM_POINTS);
points.add(pos);
}
Line3D line = new Line3D(points, 1, color);
line.setMaterial(lineMaterial);
line.setPosition(position);
getCurrentScene().addChild(line);
}
public void initScene() {
SimpleMaterial material = new SimpleMaterial();
material.setUseSingleColor(true);
// -- "curve1" will be the original curve. Note that we create two curves for
// demonstration purposes only. You'd typically create one curve and then
// reparametrize it.
CatmullRomCurve3D curve1 = new CatmullRomCurve3D();
CatmullRomCurve3D curve2 = new CatmullRomCurve3D();
for (int i = 0; i < 16; i++) {
// -- generate a random point within certain limits
Vector3 pos = new Vector3(-1 + (Math.random() * 2), -1.2f + (Math.random() * 2.4f), 0);
curve1.addPoint(pos);
curve2.addPoint(pos);
// -- add a wireframe cube so we can see what the original
// points were
Cube s = new Cube(.06f);
s.setMaterial(material);
s.setColor(CURVE1_COLOR);
s.setPosition(pos);
s.setDrawingMode(GLES20.GL_LINES);
addChild(s);
}
// -- draw the first curve
drawCurve(curve1, CURVE1_COLOR, new Vector3());
BaseObject3D pathFollowObject = new Sphere(.04f, 16, 16);
pathFollowObject.setColor(CURVE1_COLOR);
pathFollowObject.setMaterial(material);
addChild(pathFollowObject);
// -- animate a sphere that follow the first curve.
// This shows the non constant speed of a non parametrized curve.
TranslateAnimation3D anim = new TranslateAnimation3D(curve1);
anim.setDuration(ANIMATION_DURATION);
anim.setTransformable3D(pathFollowObject);
anim.setRepeatMode(RepeatMode.REVERSE_INFINITE);
registerAnimation(anim);
anim.play();
// -- reparametrize the curve for uniform distribution
curve2.reparametrizeForUniformDistribution(curve2.getPoints().size() * 4);
List<Vector3> points = curve2.getPoints();
// -- put spheres on the curve where the new points are
for (int i = 0; i < points.size(); i++) {
Vector3 pos = points.get(i);
Sphere s = new Sphere(.02f, 4, 4);
s.setMaterial(material);
s.setColor(CURVE2_COLOR);
s.setPosition(pos);
addChild(s);
}
// -- draw the second, reparametrized, curve
drawCurve(curve2, CURVE2_COLOR, new Vector3());
pathFollowObject = new Sphere(.04f, 16, 16);
pathFollowObject.setColor(CURVE2_COLOR);
pathFollowObject.setMaterial(material);
addChild(pathFollowObject);
// -- animate a sphere on the second curve.
// This shows a more or less constant speed of a parametrized curve.
anim = new TranslateAnimation3D(curve2);
anim.setDuration(ANIMATION_DURATION);
anim.setTransformable3D(pathFollowObject);
anim.setRepeatMode(RepeatMode.REVERSE_INFINITE);
registerAnimation(anim);
anim.play();
}