Texture coordinate generation is the concept of automatically
generating vertex texture coordinates instead of using the provided
coordinates (i.e. `glTexCoord`).
This commit implements support for:
* The `GL_TEXTURE_GEN_Q/R/S/T` capabilities
* The `GL_OBJECT_LINEAR`, `GL_EYE_LINEAR`, `GL_SPHERE_MAP`,
`GL_REFLECTION_MAP` and `GL_NORMAL_MAP` modes
* Object and eye plane coefficients (write-only at the moment)
This changeset allows Tux Racer to render its terrain :^)
Now that we calculate and store eye coordinates for each vertex, we
should use their `z` values for the fragment depth used in further fog
calculations.
This fixes the fog in Tux Racer :^)
This follows the OpenGL 1.5 spec much more closely. We need to store
the eye coordinates especially, since they are used in texture
coordinate generation and fog fragment depth calculation.
* LibGL now supports the `GL_NORMALIZE` capability
* LibSoftGPU transforms and normalizes the vertices' normals
Normals are heavily used in texture coordinate generation, to be
implemented in a future commit.
In the OpenGL fixed function pipeline, alpha testing should happen
before depth testing and writing. Since the tests are basically boolean
ANDs, we can reorder them however we like to improve performance and as
such, we perform early depth testing and delay the more expensive alpha
testing until we know which pixels to test.
However, we were already writing to the depth buffer during the depth
test, even if the alpha test fails later on. Depth writing should only
happen if depth testing _and_ writing is enabled.
This change introduces depth staging, deferring the depth write until
we are absolutely sure we should do so.
According to the Khronos FAQ on texture edge sampling, the `GL_CLAMP`
option was never implemented in hardware and as such, it was
deprecated. A lot of applications and games depend on `GL_CLAMP` not
really meaning `GL_CLAMP` but `GL_CLAMP_TO_EDGE`, so we introduce an
option to toggle this behavior at compile-time.
According to the documentation, we should switch around vertices every
other triangle to prevent front-face culling from removing them.
This allows Tux in Tux Racer to render correctly.
This adds a method `info()` to SoftGPU that returns the name of the
hardware vendor and device name, as well as the number of texture untis.
LibGL uses the returned texture unit count to initialize its internal
texture unit array.
Replaces the GLenum used in RasterizerConfig to select the draw buffer
with a simple boolean that disabled color output when the draw buffer
is set to GL_NONE on the OpenGL side.
We now sample textures from the device owned image samplers.
Passing of enabled texture units has been simplified by only passing a
list of texture unit indices.
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.
This introduces a new library, LibSoftGPU, that incorporates all
rendering related features that formerly resided within LibGL itself.
Going forward we will make both libraries completely independent from
each other allowing LibGL to load different, possibly accelerated,
rendering backends.
