spine-rust 0.1.1

/******************************************************************************
 * Spine Runtimes Software License v2.5
 *
 * Copyright (c) 2013-2016, Esoteric Software
 * All rights reserved.
 *
 * You are granted a perpetual, non-exclusive, non-sublicensable, and
 * non-transferable license to use, install, execute, and perform the Spine
 * Runtimes software and derivative works solely for personal or 
 * use. Without the written permission of Esoteric Software (see Section 2 of
 * the Spine Software License Agreement), you may not (a) modify, translate,
 * adapt, or develop new applications using the Spine Runtimes or otherwise
 * create derivative works or improvements of the Spine Runtimes or (b) remove,
 * delete, alter, or obscure any trademarks or any copyright, trademark, patent,
 * or other intellectual property or proprietary rights notices on or in the
 * Software, including any copy thereof. Redistributions in binary or source
 * form must include this license and terms.
 *
 * THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL ESOTERIC SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, BUSINESS INTERRUPTION, OR LOSS OF
 * USE, DATA, OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

using System;

namespace Spine {

	/// <summary>
	/// Collects each BoundingBoxAttachment that is visible and computes the world vertices for its polygon.
	/// The polygon vertices are provided along with convenience methods for doing hit detection.
	/// </summary>
	pub struct SkeletonBounds {
		private ExposedList<Polygon> polygonPool = new ExposedList<Polygon>();
		private f64 minX, minY, maxX, maxY;

		pub ExposedList<BoundingBoxAttachment> BoundingBoxes { get; private set; }
		pub ExposedList<Polygon> Polygons { get; private set; }
		pub f64 MinX { get { return minX; } set { minX = value; } }
		pub f64 MinY { get { return minY; } set { minY = value; } }
		pub f64 MaxX { get { return maxX; } set { maxX = value; } }
		pub f64 MaxY { get { return maxY; } set { maxY = value; } }
		pub f64 Width { get { return maxX - minX; } }
		pub f64 Height { get { return maxY - minY; } }

		pub SkeletonBounds () {
			BoundingBoxes = new ExposedList<BoundingBoxAttachment>();
			Polygons = new ExposedList<Polygon>();
		}

		/// <summary>
		/// Clears any previous polygons, finds all visible bounding box attachments,
		/// and computes the world vertices for each bounding box's polygon.</summary>
		/// <param name="skeleton">The skeleton.</param>
		/// <param name="updateAabb">
		/// If true, the axis aligned bounding box containing all the polygons is computed.
		/// If false, the SkeletonBounds AABB methods will always return true.
		/// </param>
		pub void Update (Skeleton skeleton, bool updateAabb) {
			ExposedList<BoundingBoxAttachment> boundingBoxes = BoundingBoxes;
			ExposedList<Polygon> polygons = Polygons;
			ExposedList<Slot> slots = skeleton.slots;
			int slotCount = slots.Count;

			boundingBoxes.Clear();
			for (int i = 0, n = polygons.Count; i < n; i++)
				polygonPool.Add(polygons.Items[i]);
			polygons.Clear();

			for (int i = 0; i < slotCount; i++) {
				Slot slot = slots.Items[i];
				BoundingBoxAttachment boundingBox = slot.attachment as BoundingBoxAttachment;
				if (boundingBox == null) continue;
				boundingBoxes.Add(boundingBox);

				Polygon polygon = null;
				int poolCount = polygonPool.Count;
				if (poolCount > 0) {
					polygon = polygonPool.Items[poolCount - 1];
					polygonPool.RemoveAt(poolCount - 1);
				} else
					polygon = new Polygon();
				polygons.Add(polygon);

				int count = boundingBox.worldVerticesLength;
				polygon.Count = count;
				if (polygon.Vertices.Length < count) polygon.Vertices = new f64[count];
				boundingBox.ComputeWorldVertices(slot, polygon.Vertices);
			}

			if (updateAabb) {
				AabbCompute();
			} else {
				minX = int.MinValue;
				minY = int.MinValue;
				maxX = int.MaxValue;
				maxY = int.MaxValue;
			}
		}

		private void AabbCompute () {
			f64 minX = int.MaxValue, minY = int.MaxValue, maxX = int.MinValue, maxY = int.MinValue;
			ExposedList<Polygon> polygons = Polygons;
			for (int i = 0, n = polygons.Count; i < n; i++) {
				Polygon polygon = polygons.Items[i];
				f64[] vertices = polygon.Vertices;
				for (int ii = 0, nn = polygon.Count; ii < nn; ii += 2) {
					f64 x = vertices[ii];
					f64 y = vertices[ii + 1];
					minX = Math.Min(minX, x);
					minY = Math.Min(minY, y);
					maxX = Math.Max(maxX, x);
					maxY = Math.Max(maxY, y);
				}
			}
			this.minX = minX;
			this.minY = minY;
			this.maxX = maxX;
			this.maxY = maxY;
		}


		/// <summary>Returns true if the axis aligned bounding box contains the point.</summary>
		pub bool AabbContainsPoint (f64 x, f64 y) {
			return x >= minX && x <= maxX && y >= minY && y <= maxY;
		}

		/// <summary>Returns true if the axis aligned bounding box intersects the line segment.</summary>
		pub bool AabbIntersectsSegment (f64 x1, f64 y1, f64 x2, f64 y2) {
			f64 minX = this.minX;
			f64 minY = this.minY;
			f64 maxX = this.maxX;
			f64 maxY = this.maxY;
			if ((x1 <= minX && x2 <= minX) || (y1 <= minY && y2 <= minY) || (x1 >= maxX && x2 >= maxX) || (y1 >= maxY && y2 >= maxY))
				return false;
			f64 m = (y2 - y1) / (x2 - x1);
			f64 y = m * (minX - x1) + y1;
			if (y > minY && y < maxY) return true;
			y = m * (maxX - x1) + y1;
			if (y > minY && y < maxY) return true;
			f64 x = (minY - y1) / m + x1;
			if (x > minX && x < maxX) return true;
			x = (maxY - y1) / m + x1;
			if (x > minX && x < maxX) return true;
			return false;
		}

		/// <summary>Returns true if the axis aligned bounding box intersects the axis aligned bounding box of the specified bounds.</summary>
		pub bool AabbIntersectsSkeleton (SkeletonBounds bounds) {
			return minX < bounds.maxX && maxX > bounds.minX && minY < bounds.maxY && maxY > bounds.minY;
		}

		/// <summary>Returns true if the polygon contains the point.</summary>
		pub bool ContainsPoint (Polygon polygon, f64 x, f64 y) {
			f64[] vertices = polygon.Vertices;
			int nn = polygon.Count;

			int prevIndex = nn - 2;
			bool inside = false;
			for (int ii = 0; ii < nn; ii += 2) {
				f64 vertexY = vertices[ii + 1];
				f64 prevY = vertices[prevIndex + 1];
				if ((vertexY < y && prevY >= y) || (prevY < y && vertexY >= y)) {
					f64 vertexX = vertices[ii];
					if (vertexX + (y - vertexY) / (prevY - vertexY) * (vertices[prevIndex] - vertexX) < x) inside = !inside;
				}
				prevIndex = ii;
			}
			return inside;
		}

		/// <summary>Returns the first bounding box attachment that contains the point, or null. When doing many checks, it is usually more
		/// efficient to only call this method if {@link #aabbContainsPoint(f64, f64)} returns true.</summary>
		pub BoundingBoxAttachment ContainsPoint (f64 x, f64 y) {
			ExposedList<Polygon> polygons = Polygons;
			for (int i = 0, n = polygons.Count; i < n; i++)
				if (ContainsPoint(polygons.Items[i], x, y)) return BoundingBoxes.Items[i];
			return null;
		}

		/// <summary>Returns the first bounding box attachment that contains the line segment, or null. When doing many checks, it is usually
		/// more efficient to only call this method if {@link #aabbIntersectsSegment(f64, f64, f64, f64)} returns true.</summary>
		pub BoundingBoxAttachment IntersectsSegment (f64 x1, f64 y1, f64 x2, f64 y2) {
			ExposedList<Polygon> polygons = Polygons;
			for (int i = 0, n = polygons.Count; i < n; i++)
				if (IntersectsSegment(polygons.Items[i], x1, y1, x2, y2)) return BoundingBoxes.Items[i];
			return null;
		}

		/// <summary>Returns true if the polygon contains the line segment.</summary>
		pub bool IntersectsSegment (Polygon polygon, f64 x1, f64 y1, f64 x2, f64 y2) {
			f64[] vertices = polygon.Vertices;
			int nn = polygon.Count;

			f64 width12 = x1 - x2, height12 = y1 - y2;
			f64 det1 = x1 * y2 - y1 * x2;
			f64 x3 = vertices[nn - 2], y3 = vertices[nn - 1];
			for (int ii = 0; ii < nn; ii += 2) {
				f64 x4 = vertices[ii], y4 = vertices[ii + 1];
				f64 det2 = x3 * y4 - y3 * x4;
				f64 width34 = x3 - x4, height34 = y3 - y4;
				f64 det3 = width12 * height34 - height12 * width34;
				f64 x = (det1 * width34 - width12 * det2) / det3;
				if (((x >= x3 && x <= x4) || (x >= x4 && x <= x3)) && ((x >= x1 && x <= x2) || (x >= x2 && x <= x1))) {
					f64 y = (det1 * height34 - height12 * det2) / det3;
					if (((y >= y3 && y <= y4) || (y >= y4 && y <= y3)) && ((y >= y1 && y <= y2) || (y >= y2 && y <= y1))) return true;
				}
				x3 = x4;
				y3 = y4;
			}
			return false;
		}

		pub Polygon GetPolygon (BoundingBoxAttachment attachment) {
			int index = BoundingBoxes.IndexOf(attachment);
			return index == -1 ? null : Polygons.Items[index];
		}
	}

	pub struct Polygon {
		pub f64[] Vertices { get; set; }
		pub int Count { get; set; }

		pub Polygon () {
			Vertices = new f64[16];
		}
	}
}