A GPU (driver) is now responsible for reading and writing pixels from
and to user data. The client (LibGL) is responsible for specifying how
the user data must be interpreted or written to.
This allows us to centralize all pixel format conversion in one class,
`LibSoftGPU::PixelConverter`. For both the input and output image, it
takes a specification containing the image dimensions, the pixel type
and the selection (basically a clipping rect), and converts the pixels
from the input image to the output image.
Effectively this means we now support almost all OpenGL 1.5 formats,
and all custom logic has disappeared from:
- `glDrawPixels`
- `glReadPixels`
- `glTexImage2D`
- `glTexSubImage2D`
The new logic is still unoptimized, but on my machine I experienced no
noticeable slowdown. :^)
This commit implements glClipPlane and its supporting calls, backed
by new support for user-defined clip planes in the software GPU clipper.
This fixes some visual bugs seen in the Quake III port, in which mirrors
would only reflect correctly from close distances.
Implement (anti)aliased point drawing and anti-aliased line drawing.
Supported through LibGL's `GL_POINTS`, `GL_LINES`, `GL_LINE_LOOP` and
`GL_LINE_STRIP`.
In order to support this, `LibSoftGPU`s rasterization logic was
reworked. Now, any primitive can be drawn by invoking `rasterize()`
which takes care of the quad loop and fragment testing logic. Three
callbacks need to be passed:
* `set_coverage_mask`: the primitive needs to provide initial coverage
mask information so fragments can be discarded early.
* `set_quad_depth`: fragments survived stencil testing, so depth values
need to be set so depth testing can take place.
* `set_quad_attributes`: fragments survived depth testing, so fragment
shading is going to take place. All attributes like color, tex coords
and fog depth need to be set so alpha testing and eventually,
fragment rasterization can take place.
As of this commit, there are four instantiations of this function:
* Triangle rasterization
* Points - aliased
* Points - anti-aliased
* Lines - anti-aliased
In order to standardize vertex processing for all primitive types,
things like vertex transformation, lighting and tex coord generation
are now taking place before clipping.
This adds a virtual base class for GPU devices located in LibGPU.
The OpenGL context now only talks to this device agnostic interface.
Currently the device interface is simply a copy of the existing SoftGPU
interface to get things going :^)
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.
This introduces a new abstraction layer, LibGPU, that serves as the
usermode interface to GPU devices. To get started we just move the
DeviceConfig there and make sure everything still works :^)
