[x3d-public] List of X3D problems or missing features, from the point of view of Michalis and Castle Game Engine

[Michalis Kamburelis]

2018-03-07 2:59 GMT+01:00 GPU Group <gpugroup at gmail.com>:
> Michalis,
> http://dug9.users.sourceforge.net/web3d/temp/lighting_4_draft0.html
> - is this what you mean for blending - changes to the lighting tables, do I
> have it right?

Your table changes on
http://dug9.users.sourceforge.net/web3d/temp/lighting_4_draft0.html
are not *exactly* what I propose.

I have updated my page
https://github.com/michaliskambi/x3d-tests/wiki/Make-RGB-and-grayscale-textures-treatment-consistent
, and included a new proposed versions of these tables, with changes
marked in bold. See the section "Exact equations change", direct link:
https://github.com/michaliskambi/x3d-tests/wiki/Make-RGB-and-grayscale-textures-treatment-consistent#exact-equations-change

Many thanks for encouraging me to do this, I think that the point is
clearer (and more precise) now.

As for why your changes on
http://dug9.users.sourceforge.net/web3d/temp/lighting_4_draft0.html
are not *exactly* what I had in mind:

1. In your table, if we have a Color node <> NULL, then you multiply
Color node (I_Crgb) with Material.diffuseColor (I_Drgb). Thus you
would change more than I propose. Right now, the X3D specification
says that the Color node (if present) effectively replaces
Material.diffuseColor, i.e. Material.diffuseColor is ignored when
Color node is present. And I do not propose to change it, as I think
it's acceptable.

    (To be clear: I would *also* be OK with multiplying
"Material.diffuseColor * Color node". But the behavior when Color node
replaces Material.diffuseColor is also OK, and this is consistently
implemented as far as I tested. So I do *not* want to break
compatibility here.)

2. You do not show that Material alpha (1-transparency) is multiplied
by texture alpha.

    (In my initial proposal version, I indeed wanted to avoid talking
about alpha. But our conversation in this thread shown me that it
should be discussed (and changed) along with RGB.)

Thank you.

Best regards,
Michalis