//

//	This example creates point locators at random surface locations,

//	and positions a Null at each of these point locators.

//	

//	Even if these point locators are simply randomly constructed,

//	this example shows how to do it in the most accurate way,

//	which is to specify subtriangles which correspond to the actual

//	polygon triangulation.

//

NewScene( null, false );

var SphereGeom = CreatePrim("Sphere", "MeshSurface").ActivePrimitive.Geometry;

var NbPtLocators = 50;

var PolygonIndexArray = new Array(NbPtLocators);

var SubTriangleVertexArray = new Array(NbPtLocators*3);

var SubTriangleWeightArray = new Array(NbPtLocators*3);

var Polygons = SphereGeom.Polygons;

for(i = 0; i < NbPtLocators; i++) {

	PolygonIndexArray[i] = Math.floor(Math.random() * 0.999999 * Polygons.Count);

	var Polygon = Polygons.Item(PolygonIndexArray[i]);

	var SubTri = Math.floor(Math.random() * 0.999999 * (Polygon.NbPoints-2));

	var PolygonVertices = Polygon.Vertices;

	var TriangleSubIndices = Polygon.TriangleSubIndexArray.toArray();

	SubTriangleVertexArray[i*3] = PolygonVertices.Item(TriangleSubIndices[SubTri*3]).Index;

	SubTriangleVertexArray[i*3+1] = PolygonVertices.Item(TriangleSubIndices[SubTri*3+1]).Index;

	SubTriangleVertexArray[i*3+2] = PolygonVertices.Item(TriangleSubIndices[SubTri*3+2]).Index;

	var W1 = Math.random();

	var W2 = Math.random();

	var W3 = Math.random();

	var WSum = W1+W2+W3;

	SubTriangleWeightArray[i*3] = W1/WSum;

	SubTriangleWeightArray[i*3+1] = W2/WSum;

	SubTriangleWeightArray[i*3+2] = W3/WSum;

}

var RandomPointLocators = SphereGeom.ConstructPointLocators(PolygonIndexArray, SubTriangleVertexArray, SubTriangleWeightArray);

CreateNullsAtPointLocations(SphereGeom, RandomPointLocators);

function CreateNullsAtPointLocations( InGeom, InPointLocators )

{

	var SpherePositions = InGeom.EvaluatePositions(InPointLocators).toArray();

	var SphereNormals = InGeom.EvaluateNormals(InPointLocators).toArray();

	var TempVector = XSIMath.CreateVector3();

	var TempRotation = XSIMath.CreateRotation();

	for (i = 0; i < SpherePositions.length; i+=3)

	{

		var NullObj = GetPrim( "Null" );

		TempVector.Set(SpherePositions[i], SpherePositions[i+1], SpherePositions[i+2]);

		NullObj.LocalTranslation = TempVector;

		TempVector.Set(SphereNormals[i], SphereNormals[i+1], SphereNormals[i+2]);

		TempRotation.SetFromXYZAxes( TempVector, TempVector, TempVector );

		NullObj.LocalRotation = TempRotation;

	}

}