texture map for 3d graphics

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Implement a full-featured texture map for 3d plots. This should support colormaps, but also mapping opacity, ambient, specular, shininess, etc.

Colormaps were first implemented in #12212, but this implementation does not easily extend to more general texture maps.

Depends on #18526

CC: @ohanar @kcrisman

Component: graphics

Branch/Commit: public/texturemap @ d3a07db

Issue created by migration from https://trac.sagemath.org/ticket/18525

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Branch: public/plot3d

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Commit: e075486

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

comment:2

Made some progress on this, but have to put it down for a little while now. There are probably errors in the current code.

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New commits:

a8fdb01	make TrianglePlot into a subclass of IndexFaceSet
d4e153a	remove specialized rendering methods which were just using those of IndexFaceSet anyway
7ade942	start of reorganizing color/texture stuff
e075486	Merge branch 'public/plot3d' of git://trac.sagemath.org/sage into plot3d-backend

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Dependencies: 18526

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Changed commit from e075486 to d3a07db

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

Changed branch from public/plot3d to public/texturemap

[9343d2e0-59ba-4406-bd4f-c78e4cf1230e]

comment:3

switch to correct branch and merged latest develop

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New commits:

2ce9508	basic texturemap class
0cc487d	getting started implementing texture maps. currently not tested at all
d3a07db	Merge branch 'develop' into public/texturemap