GL_CLAMP (clamp to border) was changed to GL_CLAMP_TO_EDGE in 2008
(f2baf359). In 2018 (ce1d5406) I made OpenGL 1.2 be required since
GL_CLAMP_TO_EDGE is used.
Restore support for GL_CLAMP in order to support OpenGL 1.1 like vanilla
Quake 3 does. This should allow using the default Microsoft Windows
GDI Generic OpenGL 1.1 driver (untested but it won't fail the version
check at least).
From gpuinfo.org, it looks like drivers stopped advertising support for
GL_SGIS_texture_edge_clamp so use a version check in addition to the
extension check.
r_allowExtensions 0 disables using GL_CLAMP_TO_EDGE in the opengl1
renderer. GL_CLAMP support wasn't added to the opengl2 renderer.
r_cubeMapping requires textureCubeLod() which is only in OpenGL 3.0
(GLSL 1.30) and later. It's not in OpenGL ES 3.0 / GLSL ES 3.00.
This needs to be checked before R_InitImages() so can't just check in
GLSL_InitGPUShaders().
Using GPU vertex skinning is significantly faster than CPU vertex
skinning. Especially since OpenGL2 has to run R_VaoPackNormal() and
R_VaoPackTangent() each vertex each frame which causes CPU vertex
skinning to be significantly slower than OpenGL1 renderer.
Load functions procs supported by OpenGL ES 2.0, though there is not a
compatible renderer yet. Change argument for GLimp_Init from coreContext
to fixedFunction.
If renderer is compiled into client (USE_RENDERER_DLOPEN=0) and after
start up set r_allowExtension to 0 and run vid_restart, some extension
were still used.
The game world is too dark when r_autoExposure is disabled. It can be
fixed by setting (cheat) r_cameraExposure to 1 but then the game is
too bright when r_autoExposure is enabled. So default r_cameraExposure
to 1 and make auto exposure subtract 1 from r_cameraExposure value.
- Parse OpenGL version in sdl_glimp.c to share with both renderers.
- Add GL_VERSION_ATLEAST(major, minor) macro.
- Get address of glGetStringi if using OpenGL 3.
- Fix glConfig.extensions_string when using GL3 core context in
opengl2 renderer.
- Make opengl1 renderer's gfxinfo support qglGetStringi too.
Get all OpenGL functions using SDL_GL_GetProcAddress(). This makes it
easier to cross-arch compile on Linux and add support for OpenGL ES
in the future.
Users still have to supply their own libSDL2 for cross-arch compiling
on Linux. But now the user does not have to re-install libgl1-mesa-dev
package for i386 or amd64 on Debian when switching between compiling
ioquake3 for x86 and x86_64.
External GLSL should probably only be used for development testing,
not released products. The GLSL files are tied to the code, and the
code changes some what often.
Fixes using OpenArena 0.8.8 which has incompatible GLSL files in a pk3.
