This is the vectorized version of `gl_tex_parameter`, which sets the
parameters of a texture's sampler. We currently only support one single
pname, `GL_TEXTURE_BORDER_COLOR`, which sets the border color of a texel
for if it is sampled outside of a mip-map's range.
We were lacking support for default textures (i.e. calling
`glBindTexture` with a `texture` argument of `0`) which caused our
Quake2 port to render red screens whenever a video was playing. Every
texture unit is now initialized with a default 2D texture.
Additionally, we had this concept of a "currently bound target" on our
texture units which is not how OpenGL wants us to handle targets.
Calling `glBindTexture` should set the texture for the provided target
only, making it sort of an alias for future operations on the same
target.
Finally, `glDeleteTextures` should not remove the bound texture from
the target in the texture unit, but it should reset it to the default
texture.
Our API still specifies it as a double, but internally we communicate a
float to the rasterizer. Additionally, clamp the value to 0..1 as
described in the spec.
The constant value for GL_DECAL is 0x2101 instead of 0x2102.
This was tripping up Half-Life when making the water texture
transparent when under water. The Half-Life port uses its own OpenGL
header, meaning this error wasn't hidden by us.
This is the equivalent of glActiveTexture() before it got promoted to
the OpenGL core specification. It is needed by glquake to enable the
multitexturing render path.
This implements an 8-bit front stencil buffer. Stencil operations are
SIMD optimized. LibGL changes include:
* New `glStencilMask` and `glStencilMaskSeparate` functions
* New context parameter `GL_STENCIL_CLEAR_VALUE`
When `GL_COLOR_MATERIAL` is enabled, specific material parameters can
be overwritten by the current color per-vertex during the lighting
calculations. Which parameter is controlled by `glColorMaterial`.
Also move the lighting calculations _before_ clipping, because the spec
says so. As a result, we interpolate the resulting vertex color instead
of the input color.
Required by Xash3D for the r_showtextures command, where it shows every
allocated texture on screen.
Description of glIsTexture from the spec:
"glIsTexture returns GL_TRUE if texture is currently the name of a
texture. If texture is zero, or is a non-zero value that is not
currently the name of a texture, or if an error occurs, glIsTexture
returns GL_FALSE.
A name returned by glGenTextures, but not yet associated with a texture
by calling glBindTexture, is not the name of a texture."
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glIsTexture.xhtml
Xash3D requires this otherwise it will crash with a jump to nullptr,
but it doesn't use it for anything interesting and just sets a default
value of ~0 during initialization.
This implements the `glLightf{v}` family of functions used to set
lighting parameters per light in the GL. It also fixes an incorrect
prototype for the user exposed version of `glLightf{v}` in which
`params` was not marked as `const`.
These stubs are largely implemented the same: their API is exposed, but
they print to the debug console and sometimes `TODO()`. These changes
allow GLU and Tux Racer to build.
Methods stubbed:
* `glTexImage1D`
* `glTexImage3D`
* `glTexCoord2d(v)`
* `glNormalPointer`
* `glTexGen(d|f|i)`
* `glTexGenfv`
Implement support for the `GL_TEXTURE` matrix mode, the texture matrix
stack and texture coordinate matrix transformation.
Also, an unused `m_current_matrix` was removed to make room for
`m_texture_matrix`.
The `glGet*` family of functions requires that all parameters of
different types are transparently converted into each other. For
example, you can request a boolean parameter as a float or a list of
double values as an integer. It might be considered bad practice to
request parameters through the wrongly-typed function, but to be spec-
compliant we need to implement this.
Introduce a new `::get_context_parameter()` to obtain a parameter
value, which is then converted to the right type by the respective
`::gl_get_*()` functions.
