[Bf-gamedev] [Bf-viewport] Viewport and shader system patches

[Ton Roosendaal]

Hi Brecht,

"Vision" is a big word, it can mean a lot. Currently there's nobody with sufficient time to tackle the design, that's true. But such problems could be solved by active recruitment and/or funding.

What I miss is a mention of using the Unreal shader design. It was suggested to align as close as possible to Unreal shaders for our 2.8 viewport, and use that to make viewport previz possible for Cycles or other engines.

I also miss active contributors giving feedback. It's not so much about ideas or visions, I want to hear what people would suggest to work on, however small it is.

Alexander: there's a whole lot of open patches from you indeed. I think we should more seriously look into that with high priority. For as long things stay compatible (old files render same), we can be quite flexible here. Provided you're around to maintain the issues a chance causes of course.

Laters,

-Ton-

--------------------------------------------------------
Ton Roosendaal  -  ton at blender.org   -   www.blender.org
Chairman Blender Foundation - Producer Blender Institute
Entrepotdok 57A  -  1018AD Amsterdam  -  The Netherlands



> On 8 Jan, 2016, at 19:26, Brecht Van Lommel <brechtvanlommel at pandora.be> wrote:
> 
> Ok, so it seems that currently there isn't really a vision for a
> better realtime shading system. At least not from people reading the
> bf-viewport and bf-gamedev mailing lists.
> 
> I'll review the patches that seem reasonable to me and don't really
> break compatibility, and those can go into Blender 2.77. For bigger
> changes someone else would need to take the responsibility.
> 
> On Fri, Jan 8, 2016 at 1:48 PM,  <a.romanov at blend4web.com> wrote:
>> 
>>> Adding these Cycles node features to BI seems all reasonable to me,
>>> particularly if the target would be to unify things more with Cycles
>>> material nodes instead of adding a completely new system
>>> specifically
>>> for the viewport.
>> It's very good, because we are primarily interested in such things.
>> And patches with support for BI and GLSL could even go into the 2.7
>> branch as it does not break backward compatibility, isn't it?
>> 
>>> 
>>> The issue with incremental changes is that you're also pretty much
>>> forced to incrementally break compatibility over many Blender
>>> versions, which is annoying for users. If it was mostly about
>>> parameters, just adding a new PBR material node would be a good
>>> solution for compatibility.
>>> 
>> Primarily we are interested in the stable branch of viewport
>> corresponding to current state of BI. So it could be 2.7 branch with
>> simplified material workflow, that could be done by adding a new PBR
>> material node.
>> 
>>> But there's issues with the way lights and materials interact, how
>>> transparency and ray tracing are wrong in subtle ways, distinctions
>>> between specular/reflection and diffuse/environment light, and more.
>>> In my experience keeping those exceptions while also adding a new
>>> PBR
>>> mode makes the code extremely complicated.
>>> 
>>> I don't want to go into too much detail here, but here's some old
>>> notes about design issues if you're interested:
>>> http://wiki.blender.org/index.php/Dev:2.5/Source/ShadingSystem/Implementation
>>> http://wiki.blender.org/index.php/User:Brecht/RenderIdeas
>>> 
>> Thanks for the tip. I need more deeply to learn.
>> 
>>> Anyway, maybe it is fine to incrementally break compatibility during
>>> the Blender 2.8 release cycle and users will just have to accept
>>> that?
>>> Whatever way we do this, it would still be good to have some kind of
>>> vision for what the end result should be.
>> In Blend4Web we keep deprecated features in 3-5 releases and our users
>> have time to adjust. But we have releases per month.
>> It's important to understand exactly what is the aim of the first
>> release of 2.8. I'm also not sure I understand. But, from the
>> conversation it seems to me that BI should stay.
>> 
>> 
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