/// <summary>
/// Function to return the object.
/// </summary>
/// <returns>The object created or updated by this builder.</returns>
/// <exception cref="GorgonException">Thrown if the polygonal sprite has less than 3 vertices.</exception>
/// <remarks>
/// <para>
/// This will return a <see cref="GorgonPolySprite"/> for use with the <see cref="Gorgon2D.DrawPolygonSprite"/> method. The object returned implements <see cref="IDisposable"/>, so it is the
/// responsibility of the user to dispose of the object when they are done with it.
/// </para>
/// <para>
/// <note type="warning">
/// <para>
/// A polygon sprite must have a minimum of 3 vertices. If it does not, then this method will throw an exception.
/// </para>
/// </note>
/// </para>
/// </remarks>
/// <seealso cref="GorgonPolySprite"/>
/// <seealso cref="Gorgon2D"/>
public GorgonPolySprite Build()
{
if (_workingSprite.RwVertices.Count < 3)
{
throw new GorgonException(GorgonResult.CannotCreate, Resources.GOR2D_ERR_POLY_SPRITE_NOT_ENOUGH_VERTS);
}
var newSprite = new GorgonPolySprite();
CopySprite(newSprite, _workingSprite);
newSprite.Renderable.ActualVertexCount = newSprite.RwVertices.Count;
if ((newSprite.Renderable.Vertices == null) || (newSprite.Renderable.Vertices.Length < newSprite.RwVertices.Count))
{
newSprite.Renderable.Vertices = new Gorgon2DVertex[newSprite.RwVertices.Count];
}
for (int i = 0; i < newSprite.RwVertices.Count; ++i)
{
newSprite.Renderable.Vertices[i] = newSprite.RwVertices[i].Vertex;
}
// Enforce clockwise ordering.
_triangulator.EnsureWindingOrder(newSprite.Renderable.Vertices, WindingOrder.CounterClockwise);
// Split the polygon hull into triangles.
(GorgonNativeBuffer <int> indices, DX.RectangleF bounds) = _triangulator.Triangulate(newSprite.Renderable.Vertices, WindingOrder.CounterClockwise);
GorgonNativeBuffer <Gorgon2DVertex> vertexData = newSprite.Renderable.Vertices.ToNativeBuffer();
try
{
newSprite.Renderable.IndexBuffer = new GorgonIndexBuffer(Graphics, new GorgonIndexBufferInfo
{
Binding = VertexIndexBufferBinding.None,
Use16BitIndices = false,
IndexCount = indices.Length,
Usage = ResourceUsage.Immutable
}, indices);
newSprite.Renderable.VertexBuffer = GorgonVertexBufferBinding.CreateVertexBuffer(Graphics, new GorgonVertexBufferInfo
{
Usage = ResourceUsage.Immutable,
Binding = VertexIndexBufferBinding.None,
SizeInBytes = Gorgon2DVertex.SizeInBytes * newSprite.RwVertices.Count
}, vertexData);
newSprite.Renderable.ActualVertexCount = newSprite.RwVertices.Count;
newSprite.Renderable.IndexCount = indices.Length;
newSprite.Bounds = new DX.RectangleF(newSprite.Position.X, newSprite.Position.Y, bounds.Width, bounds.Height);
}
finally
{
vertexData?.Dispose();
indices?.Dispose();
}
return(newSprite);
}
