Since some of those function pointers are direct GL functions the function
prototype needs the WINE_GLAPI calling convention. This makes prevents
drawStridedSlow from crashing with USE_WIN32_OPENGL.
If we're heading out of the pixelshader handler early, and a pixel
shader is in use, the pixel shader may not be compiled. The vertex
shader handler then checks if the pixel shader is dirty, and calls the
shader backend to apply the shader if it isn't. Thus, in the case of
GLSL, the shader code could attempt to link an uncompiled shader into
the program. This isn't much of a problem because when the fog is
applied, the pixel shader is compiled and the program re-linked.
GL_RGBA doesn't gaurantee an internal storage depth, which can cause the test
to fail if it's stored with less than 8 bits of precision. Some nVidia
drivers would actually store with 4 bits of precision.
Although sharing FBOs across contexts is allowed by EXT_framebuffer_object
(issue 76), it causes issues with nVidia drivers. Considering the GL 3 spec
explicitly disallows sharing of FBOs accross contexts (Appendix D), this
patch is probably the right thing to do.
There's no need to do that with the nvts and opengl ffp fixed function
fragment pipeline, it's perfectly well defined in GL which one takes
effect. This removes a few more troubles when switching between
shaders and arbfp.
ARB and GLSL don't need that. If a shader backend like atifs or nvts
need it in the future, the shader backend should deal with that rather
than the ffp pipeline.
Half Life 2 uses D3DFMT_X8R8G8B8 for the back buffer, but macos
supports aux buffers only on D3DFMT_A8R8G8B8. I think having aux
buffers is more important right now than having a precise alpha
match.
If a format is not supported natively by opengl, a shader may be able
to convert it. Up to now, CheckDeviceFormat had magic knowldge which
GL extensions lead to which supported format. This patch adds
functions that allow CheckDeviceFormat to ask the actual
implementation for its capabilities.
DDraw can draw to the front buffer only, thus there's never a Present
call which could pass this window. Due to that a drawing-independent
method is needed.
Stefan Dösinger