LSC: Texture Mapping extension


Re: LSC: Texture Mapping extension
#2
Sorry to immediately reply to my own post, but I don't feel the information here belongs in the original post. I have some comments to make about the proposed specification for texture maps.

First of all, the extension was specifically designed so that files with texture maps could be loaded in old renderers and still present something to the user that wasn't complete garbage. That's why most texture mapped geometry will be prefixed with 0 !: (to hide it from old renderers), and the reason behind the 0 !TEXMAP FALLBACK command.

Having said that, it is expected that files will be created with textures for the main detail, and placeholders for the fallback geometry. It is also expected that texture mapped versions of existing patterned parts will be created, and for those, the existing full pattern geometry would be used as the fallback. As it happens, the sample files contain both types of files. The following files have both texture maps and full fallback geometry:

970c00px50.dat
973pa9.dat
3068p101.dat

The following file has blank fallback geometry:

3068px01.dat

The following file has red fallback geometry:

3626bpx395.dat

LDView 4.2 Beta 1 contains a "Use texture maps" check box in the Primitives tab of its preferences. The Windows and Mac versions allow you to put this in the toolbar. (The Linux toolbar still can't be customized.) Toggle that setting with the above files loaded to see what happens. This version does not support POV exporting of textured parts. And in fact, if the textures feature is enabled, you'll get bad results, as it outputs both sets of geometry (but without the texture map). I will fix it to either support textures or at least go into correct fallback mode sometime between the Beta release and the official 4.2 release.

If we ratify this texture maps extension, we'll need to update the official parts restrictions document to specify things like maximum texture resolution and requirements for fallback geometry. I don't think we should require the fallback geometry to be anywhere near as good as it is now for patterned parts (although Needs Work might be required if it isn't). One of the reasons for this extension was to make it easier to create patterned parts. And if we require them to have just as much geometric detail as they have right now, but allow them to also have a texture map, that just makes it harder to create them, not easier.

Some of the sample files contain BFC errors. Please disable BFC when looking at them. Real files would obviously not be allowed to have BFC errors.

Support for textures would have to be added to the Parts Tracker. Also, while it's not in the spec yet, it is expected that textures will be placed into a subdirectory. LDView automatically prepends "textures/" to the PNG image's filename. It then uses its standard search path searching to find the file. If that fails, it repeats the process without prepended "textures/". The expectation is that texture files would go into a new <LDraw>/parts/textures directory.
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Re: LSC: Texture Mapping extension - by Travis Cobbs - 2012-04-08, 4:18

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