In its current form this is quite useless. What's really needed is to require a lock on the RenderBuffer for the 3D scene, but since this is not needed for the 2D stuff anymore it can be done far simpler.
I have no idea why they were even in there, as they intentionally circumvented all GC related features - they declared themselves fixed if prone to getting collected, they all used OF_YesReallyDelete when destroying themselves and they never used any of the object creation or RTTI features, aside from a single assert in V_Init2.
Essentially they were a drag on the system and OF_YesReallyDelete was effectively added just to deal with the canvases which were DObjects but not supposed to behave like them in the first place.
- check and use WGL_EXT_swap_control_tear extension. The above change makes the system always wait for a full vsync with a wglSwapInterval of 1, so it now uses the official extension that enables adaptive vsync. Hopefully this also works on the cards where the old setup did not.
After doing some profiling it was very obvious that this has better performance than client arrays. Persistent buffers are still better, though, especially for handling dynamic lights.
GLEW has two major problems:
- it always includes everything, there is no way to restrict the header to a specific GL version
- it is mostly broken with a core profile and only works if all sanity checks get switched off.
There was one issue preventing the previous 2.0 betas from running under GL 3.x: The lack of persistently mapped buffers.
For the dynamic light buffer today's changes take care of that problem.
For the vertex buffer there is no good workaround but we can use immediate mode render calls instead which have been reinstated.
To handle the current setup, the engine first tries to get a core profile context and checks for presence of GL 4.4 or the GL_ARB_buffer_storage extension.
If this fails the context is deleted again and a compatibility context retrieved which is then used for 'old style' rendering which does work on older GL versions.
This new version does not support GL 3.2 or lower, meaning that Intel GMA 3000 or lower is not supported. The reason for this is that the engine uses a few GL 3.3 features which are not present in the latest Intel driver.
In general the Intel GMA 3000 is far too weak, though, to run the demanding shader of GZDoom 2.x, so this is no real loss. Performance would be far from satisfying.
A command line option '-gl3' exists to force the fallback render path. On my Geforce 550Ti there's approx. 10% performance loss on this path.
- removed gl_vid_compatibility. With the bump to 1.4 no hardware requiring this flag is supported anymore.
- disabled 16 bit framebuffers for the same reason. As a conseqence all code for rendering without stencil could also be removed.
