//----------------------------------------------

//            NGUI: Next-Gen UI kit

// Copyright © 2011-2013 Tasharen Entertainment

//----------------------------------------------



using UnityEngine;

using System.Collections.Generic;



/// <summary>

/// Generated geometry class. All widgets have one.

/// This class separates the geometry creation into several steps, making it possible to perform

/// actions selectively depending on what has changed. For example, the widget doesn't need to be

/// rebuilt unless something actually changes, so its geometry can be cached. Likewise, the widget's

/// transformed coordinates only change if the widget's transform moves relative to the panel,

/// so that can be cached as well. In the end, using this class means using more memory, but at

/// the same time it allows for significant performance gains, especially when using widgets that

/// spit out a lot of vertices, such as UILabels.

/// </summary>



public class UIGeometry

{

	/// <summary>

	/// Widget's vertices (before they get transformed).

	/// </summary>



	public BetterList<Vector3> verts = new BetterList<Vector3>();



	/// <summary>

	/// Widget's texture coordinates for the geometry's vertices.

	/// </summary>



	public BetterList<Vector2> uvs = new BetterList<Vector2>();



	/// <summary>

	/// Array of colors for the geometry's vertices.

	/// </summary>



	public BetterList<Color32> cols = new BetterList<Color32>();



	// Relative-to-panel vertices, normal, and tangent

	BetterList<Vector3> mRtpVerts = new BetterList<Vector3>();

	Vector3 mRtpNormal;

	Vector4 mRtpTan;



	/// <summary>

	/// Whether the geometry contains usable vertices.

	/// </summary>



	public bool hasVertices { get { return (verts.size > 0); } }



	/// <summary>

	/// Whether the geometry has usable transformed vertex data.

	/// </summary>



	public bool hasTransformed { get { return (mRtpVerts != null) && (mRtpVerts.size > 0) && (mRtpVerts.size == verts.size); } }



	/// <summary>

	/// Step 1: Prepare to fill the buffers -- make them clean and valid.

	/// </summary>



	public void Clear ()

	{

		verts.Clear();

		uvs.Clear();

		cols.Clear();

		mRtpVerts.Clear();

	}



	/// <summary>

	/// Step 2: After the buffers have been filled, apply the specified pivot offset to the generated geometry.

	/// </summary>



	public void ApplyOffset (Vector3 pivotOffset)

	{

		for (int i = 0; i < verts.size; ++i) verts.buffer[i] += pivotOffset;

	}



	/// <summary>

	/// Step 3: Transform the vertices by the provided matrix.

	/// </summary>



	public void ApplyTransform (Matrix4x4 widgetToPanel, bool normals)

	{

		if (verts.size > 0)

		{

			mRtpVerts.Clear();

			for (int i = 0, imax = verts.size; i < imax; ++i) mRtpVerts.Add(widgetToPanel.MultiplyPoint3x4(verts[i]));



			// Calculate the widget's normal and tangent

			mRtpNormal = widgetToPanel.MultiplyVector(Vector3.back).normalized;

			Vector3 tangent = widgetToPanel.MultiplyVector(Vector3.right).normalized;

			mRtpTan = new Vector4(tangent.x, tangent.y, tangent.z, -1f);

		}

		else mRtpVerts.Clear();

	}



	/// <summary>

	/// Step 4: Fill the specified buffer using the transformed values.

	/// </summary>



	public void WriteToBuffers (BetterList<Vector3> v, BetterList<Vector2> u, BetterList<Color32> c, BetterList<Vector3> n, BetterList<Vector4> t)

	{

		if (mRtpVerts != null && mRtpVerts.size > 0)

		{

			if (n == null)

			{

				for (int i = 0; i < mRtpVerts.size; ++i)

				{

					v.Add(mRtpVerts.buffer[i]);

					u.Add(uvs.buffer[i]);

					c.Add(cols.buffer[i]);

				}

			}

			else

			{

				for (int i = 0; i < mRtpVerts.size; ++i)

				{

					v.Add(mRtpVerts.buffer[i]);

					u.Add(uvs.buffer[i]);

					c.Add(cols.buffer[i]);

					n.Add(mRtpNormal);

					t.Add(mRtpTan);

				}

			}

		}

	}

}