This introduces a new device independent base class for Images in LibGPU
that also keeps track of the device from which it was created in order
to prevent assigning images across devices.
Between the OpenGL client and server, a lot of data type and color
conversion needs to happen. We are performing these conversions both in
`LibSoftGPU` and `LibGL`, which is not ideal. Additionally, some
concepts like the color, depth and stencil buffers should share their
logic but have separate implementations.
This is the first step towards generalizing our `LibSoftGPU` frame
buffer: a generalized `Typed3DBuffer` is introduced for arbitrary 3D
value storage and retrieval, and `Typed2DBuffer` wraps around it to
provide in an easy-to-use 2D pixel buffer. The color, depth and stencil
buffers are replaced by `Typed2DBuffer` and are now managed by the new
`FrameBuffer` class.
The `Image` class now uses multiple `Typed3DBuffer`s for layers and
mipmap levels. Additionally, the textures are now always stored as
BGRA8888, only converting between formats when reading or writing
pixels.
Ideally this refactor should have no functional changes, but some
graphical glitches in Grim Fandango seem to be fixed and most OpenGL
ports get an FPS boost on my machine. :^)
This adds two methods, write_texels and read_texels, to the Image class.
Conversion between image formats happens automatically. The layout of
the client image data is passed in via ImageDataLayout struct.
This serves as the storage for all image types. 1D, 2D, 3D, Cube and
image arrays.
Upon construction a full mipmap chain is generated and the image is
immutable afterwards with respect to its layout.
