/******************************************************************************
 * Spine Runtime Software License - Version 1.1
 * 
 * Copyright (c) 2013, Esoteric Software
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms in whole or in part, with
 * or without modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. A Spine Essential, Professional, Enterprise, or Education License must
 *    be purchased from Esoteric Software and the license must remain valid:
 *    http://esotericsoftware.com/
 * 2. Redistributions of source code must retain this license, which is the
 *    above copyright notice, this declaration of conditions and the following
 *    disclaimer.
 * 3. Redistributions in binary form must reproduce this license, which is the
 *    above copyright notice, this declaration of conditions and the following
 *    disclaimer, in the documentation and/or other materials provided with the
 *    distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 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;
using System.Collections.Generic;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework;

namespace Spine {
	public class SkeletonRenderer {
		GraphicsDevice device;
		SpriteBatcher batcher;
		BasicEffect effect;
		RasterizerState rasterizerState;
		float[] vertices = new float[8];
		BlendState defaultBlendState;

		private bool premultipliedAlpha;
		public bool PremultipliedAlpha { get { return premultipliedAlpha; } set { premultipliedAlpha = value; } }

		public SkeletonRenderer (GraphicsDevice device) {
			this.device = device;

			batcher = new SpriteBatcher();

			effect = new BasicEffect(device);
			effect.World = Matrix.Identity;
			effect.View = Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 1.0f), Vector3.Zero, Vector3.Up);
			effect.TextureEnabled = true;
			effect.VertexColorEnabled = true;

			rasterizerState = new RasterizerState();
			rasterizerState.CullMode = CullMode.None;

			Bone.yDown = true;
		}

		public void Begin () {
			defaultBlendState = premultipliedAlpha ? BlendState.AlphaBlend : BlendState.NonPremultiplied;

			device.RasterizerState = rasterizerState;
			device.BlendState = defaultBlendState;

			effect.Projection = Matrix.CreateOrthographicOffCenter(0, device.Viewport.Width, device.Viewport.Height, 0, 1, 0);
		}

		public void End () {
			foreach (EffectPass pass in effect.CurrentTechnique.Passes) {
				pass.Apply();
				batcher.Draw(device);
			}
		}

		public void Draw (Skeleton skeleton) {
			List<Slot> drawOrder = skeleton.DrawOrder;
			float x = skeleton.X, y = skeleton.Y;
			float skeletonR = skeleton.R, skeletonG = skeleton.G, skeletonB = skeleton.B, skeletonA = skeleton.A;
			for (int i = 0, n = drawOrder.Count; i < n; i++) {
				Slot slot = drawOrder[i];
				RegionAttachment regionAttachment = slot.Attachment as RegionAttachment;
				if (regionAttachment != null) {
					BlendState blend = slot.Data.AdditiveBlending ? BlendState.Additive : defaultBlendState;
					if (device.BlendState != blend) {
						End();
						device.BlendState = blend;
					}

					SpriteBatchItem item = batcher.CreateBatchItem();
					AtlasRegion region = (AtlasRegion)regionAttachment.RendererObject;
					item.Texture = (Texture2D)region.page.rendererObject;

					Color color;
					float a = skeletonA * slot.A;
					if (premultipliedAlpha)
						color = new Color(skeletonR * slot.R * a, skeletonG * slot.G * a, skeletonB * slot.B * a, a);
					else
						color = new Color(skeletonR * slot.R, skeletonG * slot.G, skeletonB * slot.B, a);
					item.vertexTL.Color = color;
					item.vertexBL.Color = color;
					item.vertexBR.Color = color;
					item.vertexTR.Color = color;

					float[] vertices = this.vertices;
					regionAttachment.ComputeWorldVertices(x, y, slot.Bone, vertices);
					item.vertexTL.Position.X = vertices[RegionAttachment.X1];
					item.vertexTL.Position.Y = vertices[RegionAttachment.Y1];
					item.vertexTL.Position.Z = 0;
					item.vertexBL.Position.X = vertices[RegionAttachment.X2];
					item.vertexBL.Position.Y = vertices[RegionAttachment.Y2];
					item.vertexBL.Position.Z = 0;
					item.vertexBR.Position.X = vertices[RegionAttachment.X3];
					item.vertexBR.Position.Y = vertices[RegionAttachment.Y3];
					item.vertexBR.Position.Z = 0;
					item.vertexTR.Position.X = vertices[RegionAttachment.X4];
					item.vertexTR.Position.Y = vertices[RegionAttachment.Y4];
					item.vertexTR.Position.Z = 0;

					float[] uvs = regionAttachment.UVs;
					item.vertexTL.TextureCoordinate.X = uvs[RegionAttachment.X1];
					item.vertexTL.TextureCoordinate.Y = uvs[RegionAttachment.Y1];
					item.vertexBL.TextureCoordinate.X = uvs[RegionAttachment.X2];
					item.vertexBL.TextureCoordinate.Y = uvs[RegionAttachment.Y2];
					item.vertexBR.TextureCoordinate.X = uvs[RegionAttachment.X3];
					item.vertexBR.TextureCoordinate.Y = uvs[RegionAttachment.Y3];
					item.vertexTR.TextureCoordinate.X = uvs[RegionAttachment.X4];
					item.vertexTR.TextureCoordinate.Y = uvs[RegionAttachment.Y4];
				}
			}
		}
	}
}