Closed JC3 closed 3 years ago
The core spec only defines the BaseMaterials as property group. Since that is a material property, it can't be interpolated, since it defines the material. This is just for using the core spec alone. However when extended with the materials spec, other property groups could be define. For example the ColorGroup, which defines the surface color as being "painted". In this case interpolation between vertex properties is allowed. The core spec just set the based for a behaviour that is defined in the materials spec.
Understood. Thank you.
J
On Fri, May 14, 2021, 12:02 PM Jordi Gonzalez @.***> wrote:
The core spec only defines the BaseMaterials as property group. Since that is a material property, it can't be interpolated, since it defines the material. This is just for using the core spec alone. However when extended with the materials spec, other property groups could be define. For example the ColorGroup, which defines the surface color as being "painted". In this case interpolation between vertex properties is allowed. The core spec just set the based for a behaviour that is defined in the materials spec.
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Section 1.3 of the Materials Extension spec reads:
Section 4.1.4 of the core spec reads:
I can't make any sense of this because:
<basematerials>
, which is implied to be a "property group". It is the only thing the Core spec identifies as such.<basematerials>
group, then all three property group indices must be the same if specified.<basematerials>
, and since all three property indices in a face must be the same if they are in<basematerials>
, then this implies that all three property indices in a face must always be the same, as there doesn't seem to be any other type of "property group" to choose from.displaycolor
attribute of a base material. When taken with the above, this implies that sRGB colors can't be assigned per vertex in a face (as I can't see any other place where a color could appear besides a base material, which restricts p1/p2/p3 to be identical).What am I missing? Where does the Core spec define sRGB triplets that can be assigned to each vertex of a triangle?
Also, if p1, p2, and p3 must always be identical (since they must refer to a "property group", of which there is only one: base materials -- for which they must be identical), why are there three separate p's and what is it referring to when it mentions interpolation?