/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public GraphicMatchingDemo(DemosGame game)
: base(game)
{
//When creating a collision shape based on a model, the graphic will generally be offset at first.
//This is because the collision shape computes the center of mass and offsets itself to align with the local origin.
//That offset must be applied to the graphic to make it match the collision shape.
//Check out the documentation page for more information:
//http://bepuphysics.codeplex.com/wikipage?title=Shape%20Recentering
var model = game.Content.Load<Model>("guy");
BEPUutilities.Vector3[] vertices;
int[] indices;
ModelDataExtractor.GetVerticesAndIndicesFromModel(model, out vertices, out indices);
//Create an entity based on the model.
ConvexHull hull = new ConvexHull(vertices, 10);
Space.Add(hull);
//Create a graphic for the hull. The BEPUphysicsDrawer will also automatically receive a visualization of the convex hull which we can compare our graphic against.
//The graphic will be offset from the collision shape because we have not attempted to offset it to match the collision shape's origin.
var graphic = new DisplayEntityModel(hull, model, game.ModelDrawer);
game.ModelDrawer.Add(graphic);
//Now let's create another entity from the same vertices.
hull = new ConvexHull(vertices, 10);
Space.Add(hull);
//Note that the prefab entity type ConvexHull uses the ConvexHullShape constructor internally, which outputs the computed center of the shape
//prior to offset. The ConvexHull constructor sets the entity's Position to that position so that the initial world space location of the vertices
//matches what was passed into the constructor.
//The same process could be performed using this code:
//Vector3 computedCenter;
//var shape = new ConvexHullShape(vertices, out computedCenter); //<-- It spits out the computed center here; this is what is used to offset the graphic!
//var entity = new Entity(shape, 10);
//entity.Position = computedCenter;
//Space.Add(entity);
//For more information about constructing entities, check out the EntityConstructionDemo.
//But for now, let's just use the prefab entity type. As mentioned earlier, the constructor set the entity's Position using the computed center.
//Since we didn't overwrite it with some other position yet, we can still use it.
graphic = new DisplayEntityModel(hull, model, game.ModelDrawer);
graphic.LocalTransform = Matrix.CreateTranslation(-hull.Position);
game.ModelDrawer.Add(graphic);
//This graphic is perfectly aligned with the collision shape! Hooray!
Box ground = new Box(new Vector3(0, -1.5f, 0), 50, 1, 50);
Space.Add(ground);
game.Camera.Position = new Vector3(0, 6, 15);
}
