Open Radar

 
Summary:
When attempting to use SKTexture creation methods with the SKMutableTexture subclass[1] some of the methods don't return a SKMutableTexture. Even when the methods *do* return a SKMutableTexture instance, calling `modifyPixelDataWithBlock:` will invoke the block with a null pixelData pointer and zero data length.

This negates most usefulness of the SKMutableTexture class because the only way to use it is to start with a blank texture of a certain size using its own initializers.

I had previously filed Radar 17400234 about this, but I closed it prematurely since my sample project only tested two of SKTexture's initializers. Upon further testing it's clear that this hasn't been fixed properly.

[1]: "To use this class, create a mutable texture using either one of its creation methods or those of its superclass"

Steps to Reproduce:
1. Install Xcode
2. Create a new SpriteKit project
3. Attempt to create an SKMutableTexture instance with `textureWithImage:` (others included in the sample project I've provided).
4. Observe that the returned instance is of type SKTexture.
5. Attempt to create an SKMutableTexture instance with `textureWithImageNamed:`
6. Observe that the returned instance is of type SKMutableTexture.
7. Attempt to mutate the image buffer with `modifyPixelDataWithBlock:`.
8. Observe that the pixelData and length arguments are invalid.

Expected Results:
I would expect to get a SKMutableTexture back that is actually mutable with its `modifyPixelDataWithBlock:` method.

Actual Results:
I only get a SKTexture back, or when I do get a SKMutableTexture back I can't use `modifyPixelDataWithBlock:` to do anything because I don't actually get the pixelData pointer and data length value passed into the block.

Version:
Xcode Version 6.0 (6A267n)
OS X 10.10 (14A298i)