[x3d-public] colorMode of PointProperties

[Andreas Plesch]

It looks like the PointProperties colorMode is a way to deal with
11.4.11 PointSet which says

"PointSet nodes are not lit, not texture-mapped, .."

although in fact points can now be texture-mapped.

Since this is a change for PointSet is might be necessary to correct
11.4.11 instead of introducing a workaround with colorMode.

"PointSet nodes are not lit. Textures are applied to the full size of
each point after blending as defined in Table 17.2."

in 11.4.11 PointSet may suffice to address all colorMode options.

On another note, should the color node be allowed to have less entries
than the total number of points, with points lacking a corresponding
color getting assigned the last color in the color node list of colors
? This makes sense for the common scenario that there a lot of points
of the same color.

-Andreas

On Fri, Nov 22, 2019 at 7:44 AM Andreas Plesch <andreasplesch at gmail.com> wrote:
>
> I am looking at colorMode field of the new PointProperties which has these options:
>
> POINT_COLOR shall display the RGB channels of the color instance defined in X3DMaterialNode or X3DColorNode, and the A channel of the texture if any. If no color is
> associated to the point, the default RGB color (0, 0, 0) shall be used.
>
> TEXTURE_COLOR shall display the original texture with its RGBA channels and regardless
> to the X3DMaterialNode or X3DColorNode which might be associated to the point set.
>
> TEXTURE_AND_POINT_COLOR shall display the RGBA channels of a texture added to the
> RGB channels of the color defined in X3DMaterialNode or X3DColorNode node, and the A
> channel of the texture if any. If no color is associated to the point, the result shall be exactly
> the same as TEXTURE_COLOR.
>
> What is the motivation, eg. what is the value over standard blending behaviour, multiplying color and texture if both are given ?
>
> Also, I do not understand how summing RGBA channels of texture and color could be useful, as required by the TEXTURE_AND_POINT_COLOR option.
>
> At this point, I would be in favour of removing the field. Instead, standard lighting behaviour would apply. Other than color blending, this may also include shading if normals are provided per point.
>
> Andreas
>


-- 
Andreas Plesch
Waltham, MA 02453