Renderer FAQ

[illwieckz]

I noticed there is a lot of misconception floating around, and some misunderstanding too.

So I did a FAQ, so people don't have te re-explain things over and over, and people can redirect to the FAQ when needed:

https://wiki.unvanquished.net/wiki/Renderer_FAQ

[illwieckz]

Example with recent things I have seen on the chat, with FAQ answers:

the complexity of implementing software variants of stuff in modern OpenGL (3+) hinders the totality of actual players for no reason

• Q: Does the old-OpenGL compatibility mode slow down the renderer on newer hardware?
• A: No, the old-OpenGL or new-OpenGL execution path is selected at map load.

someone could of course also mention the insistance to keep more than antiquated openGL support (even recent openGL are obsolete, mind you) in the core rendering, preventing the use of nice features that allow mesh instancing, which have the potential to drastically drop the rendering cost

• Q: Do you have a plan for Vulkan?
• A: Yes, a Vulkan renderer is in development.

• Q: Will you provide a renderer free of support from very old hardware?
• A: Yes, the Vulkan renderer is meant to drop support for very old hardware.

the sRGB can be useful, as long as it does not impacts old maps

• Q: Can a legacy map be mistakenly rendered with the linear lighting?
• A: No, maps have to be explicitly rebuilt for the linear lighting for the engine to use linear lighting.

• Q: Is it still possible to rebuild maps the old way?
• A: Yes, we provide multiple old map build presets. The renderer keeps the support for what is built the old way.

there are hundreds of other dark maps we could see in nice light with adaptive exposure. but you blocked that
you dismissed it in favour of your srgb thing

• Q: Will you provide adaptive lighting?
• A: Adaptive lighting work is planned, it is in progress but not merged yet.

• Q: Are the linear lighting (sRGB support) and adaptive lighting meant to work together?
• A: Yes, in fact, both linear lighting, tone mapping and adaptive lighting are not only meant to work together, they are cumulative. Adaptive lighting requires tone mapping to work and requires linear lighting to be correct.

you made considerable changes to how a map's lighting is displayed. thankfully, you rolled back the most invasive changes.

• Q: Did you change the way the map lighting was rendered?
• A: No, but we added a new way to process lighting (linear lighting, aka sRGB support).

• Q: Does the linear lighting (sRGB support) change the way existing maps are rendered?
• A: No, maps have to be explicitly rebuilt for the linear lighting for the engine to use linear lighting.

• Q: Did the overbright patches change the way legacy maps are rendered?
• A: No, they restored the way legacy maps were rendered. Previously we had a bug, so if you see a change, it's because a bug was misrendering something before.

• Q: Did you have to rollback the overbright support?
• A: No, our first fix was incomplete when we released it first, we then shipped an additional fix to finish the compatibility support. It's incremental improvement.