[x3d-public] X3D Agenda 19 June 2020: Mantis issues

GPU Group gpugroup at gmail.com
Fri Jun 19 08:22:11 PDT 2020


Got it, thanks!

On Fri, Jun 19, 2020 at 8:56 AM Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> As for PBR notes:
>
> pt., 19 cze 2020 o 16:37 GPU Group <gpugroup at gmail.com> napisał(a):
>
>> 1269            glTF physically based rendering PBR, advanced material
>> textures and lighting
>>
>> - freewrl implemented except EnvironmentLight. and direct gltf loading
>>
>> - freewrl: no objection to EnvironmentLight - (freewrl needs work)
>>
>>
>>
>> related: MultiTexture conundrum not solved:
>>
>> --Lighting model implies texture is an input to lighting so comes first,
>>
>> -- Multitexture implies Lighting comes first, so REPLACE can replace
>>
>> pre-PBR technique: put (1,1,1,1) as placeholder for texture, in Lighting,
>> and modulate output diffuse component with Multitexture
>>
>> post-PBR method: Physical lighting doesn't have compoentents, so can't
>> post-modulate to solve conundrum
>>
>> Options:
>>
>> 1) Multitexture's a priori Lighting would be Gouraud / vertex shader
>> lighting, multitexture applied before Phong/frag lighting
>>
>> 2) Multitexture not applied to Physical
>>
>>
> My PR contains a prose how to deal with MultiTexture . It should work in
> all lighting models (Material, PhysicalMaterial, UnlitMaterial) in a way
> that is also backward-compatible.
>
> My PR will also contain (I have it written locally, not yet in the spec)
> what to do when browser wants to use Gouraud shading. This decision is
> independent from the lighting model. As in X3D 3, you can use Gouraud
> shading or Phong shading with Phong lighting model (Material node) or
> others. The lighting equations (in X3D 3 already) actually require using
> Phong shading (since they say that texture should only affect diffuse), but
> I want to recognize that most (all?) X3D browsers, including FreeWRL and
> view3dscene, enable both Gouraud shading and Phong shading, and add
> clarification how to deal with Gouraud shading to the spec.
>
> Regards,
> Michalis
>
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