Open gl question

[tyrzi]

OK! This might be over 9000th same question than before, but anyway.
Why open GL is removed? Over 75% (my guess) people want it back, so why it isn't coming back then. I am the one who want open GL back too.
I know there is some kind of major problems and errors in open GL mode but still, I don't have any idea what those problems are and why.
+ I tried open GL mode in SRB2ME, http://mb.srb2.org/showpost.php?p=628486&postcount=1 and I saw just 1 problem... spikes, and in that open GL "version", when I put sound effects on, I get sigsevd.

But I, and other 75% want it back.

 

[SSNTails]

I think GL is still missing a few more things. Random polygons missing, and proper model & sprite clipping against colormaps. Either sprites need to be split in two like in software mode, or mess with the stencil buffer or whatever Shadow Hog was talking about.

The sprite offsets also need to be fixed for MFE_VERTICALFLIP sprites. They are a little too high into the ceiling.

The GL_ALPHA_TEST functionality isn't working right. It would be perfect if we didn't have any translucent sprites, but we do. I would suggest sorting the sprites in HWR_CreateDrawNodes along with the translucent walls and flats. If this is done, GL_ALPHA_TEST can be disabled. It also looks prettier if you do it this way.

Another issue is that we render the level geometry 3 different times to make sure everything is included (see HWR_RenderBspNode). This causes translucent walls to be drawn more than once per frame, which causes the translucency levels to flicker and change. Each polygon in the level should be marked with a 'drawn' counter to make sure it doesn't get drawn more than once per frame.
Of course, since between the 3 rendering passes it's possible more translucent walls can pop up, you need to cache all of the HWR_CreateDrawNodes across the 3 passes and then render the translucent/transparent/alpha stuff AFTER the 3 passes are completed.
Right now I think a counter is kept as the BSP is traversed to help in sorting the translucent walls/flats. This works for comparing polygons within a single passes, but comparing across passes it's useless. Some other technique needs to be devised for comparing cross-pass polygons.

Also, fog block rendering.

 

[MascaraSnake]

While SSNTails gave an accurate description about the issues that need to be addressed, I doubt that it is that easy to understand.

Basically, there are several problems with OpenGL. The most irritating for the casual player would be the fact that fog blocks don't work. For instance, the lasers in the first room in Egg Rock Zone Act 1 are invisible in OpenGL. That makes the level hard to complete if you don't know where they are. There are more issues, like the broken fences in ACZ1 and several other visual glitches, but this is probably the one that breaks OpenGL the most. As far as I know, the dev team is working on fixing the render, so it's probably gonna return sometime in the future. For now, Software should be fine for most needs.

 

[tyrzi]

Thanks to ssntails and spiritcrusher: giving me information why GL is broken.
and extra thanks to spiritcrusher: giving me that information that they are trying to fix GL.