Combine Texture Frames Tool for Unity 5

CombineTextureFrames.cs

using UnityEngine;
using UnityEditor;
using System.Linq;

public class CombineTextureFrames : ScriptableWizard {

	public Texture2D[] textures;
	public Vector2 frameSize;
	public Vector2 layout;

	[MenuItem("Assets/Combine Texture Frames")]
	static void CreateWizard () {
		var wizard = ScriptableWizard.DisplayWizard<CombineTextureFrames> ("Combine Texture Frames", "Save");
		var textures = Selection.objects.Where (o => o is Texture2D)
			.OrderBy (o => o.name, new FileNameComparer())
				.Cast<Texture2D> ().ToArray ();

		wizard.textures = textures;

		if (textures.Length == 0) {
			wizard.frameSize = Vector2.zero;
			wizard.layout = Vector2.zero;
		}
		else {
			int width = int.MaxValue;
			int height = int.MaxValue;
			foreach (var t in textures) {
				width = Mathf.Min (width, t.width);
				height = Mathf.Min (height, t.height);
			}
			wizard.frameSize = new Vector2 (width, height);
			int fullArea = width * height * textures.Length;
			float squareSize = Mathf.Sqrt ((float) fullArea);
			int layoutX = (int) Mathf.Ceil (squareSize / (float) width);
			int layoutY = (textures.Length - 1) / layoutX + 1;
			wizard.layout = new Vector2 (layoutX, layoutY);
		}
	}

	void OnWizardCreate () {
		var width = (int) (this.frameSize.x * this.layout.x);
		var height = (int) (this.frameSize.y * this.layout.y);
		var texResult = new Texture2D (width, height, TextureFormat.Alpha8, true);
		int frameWidth = (int) this.frameSize.x;
		int frameHeight = (int) this.frameSize.y;
		int layoutWidth = (int) this.layout.x;
		int layoutHeight = (int) this.layout.y;
		int layoutX = 0;
		int layoutY = 0;
		foreach (var tex in this.textures) {
			texResult.SetPixels(
				layoutX * frameWidth, layoutY * frameHeight, frameWidth, frameHeight,
				tex.GetPixels (0, 0, frameWidth, frameHeight));
			if (++layoutX >= layoutWidth) {
				++layoutY;
				layoutX = 0;
			}
		}
		texResult.Apply ();
		var savePath = EditorUtility.SaveFilePanelInProject (
			"Save the result", "texture", "png", "Save the result");
		if (savePath != null) {
			var bytes = texResult.EncodeToPNG ();
			System.IO.File.WriteAllBytes (savePath, bytes);
			AssetDatabase.ImportAsset (savePath);
		}
	}

	class FileNameComparer : System.Collections.Generic.IComparer<string> {
		#region IComparer implementation

		public int Compare (string x, string y)
		{
			Debug.LogFormat ("Compare {0} {1}", x, y);
			int posX = 0;
			int posY = 0;
			while (true) {
				if (posX == x.Length) {
					return posY == y.Length ? 0 : -1;
				}
				if (posY == y.Length) {
					return 1;
				}
				char cx, cy;
				int nx, ny;
				posX = eatString(x, posX, out cx, out nx);
				posY = eatString(y, posY, out cy, out ny);
				var charResult = System.Collections.Generic.Comparer<char>.Default.Compare (cx, cy);
				if (charResult != 0) {
					return charResult;
				}
				var intResult = System.Collections.Generic.Comparer<int>.Default.Compare (nx, ny);
				if (intResult != 0) {
					return intResult;
				}
			}
		}

		#endregion

		private static int eatString (string s, int pos, out char c, out int n) {
			c = s[pos];
			n = 0;
			if (c < '0' || c > '9') {
				return pos + 1;
			}
			while (true) {
				n = n * 10 + (c - '0');
				++pos;
				if (pos == s.Length)
					break;
				c = s[pos];
				if (c < '0' || c > '9')
					break;
			}
			c = '0';
			return pos;
		}
	}
}