Simdify Platform

Fixed unexpected behavior in <TextureReadbackImageProcessor>. This object uses a <TextureReadbackParams> data member to store readback parameters. The <TextureReadbackParams> object itself has a data member c_nDepth that was initialized to 0. Readbacks generally will not work capture anything when this value is 0. The most useful default value is 1. The c_nDepth value works in concert with the c_nOffetZ value to allow readback for a range of slices of a layered texture. You can assume that in most cases, you want to capture at least 1 layer.

For example, in a texture with 10 layers, and layer indices 0-9, you might set c_nOffetZ to 4 and c_nDepth to 1 if you want to capture a single layer, starting at layer index 4. You could set c_nDepth to 3 to readback three layers.

Readbacks are now created with appropriate default values, so they should 'just work' all the time.