"The texture texture-filename is a uniform color."
This message indicates that the entirety of the specified texture file is the same color.
This is an error for content at trainz-build 3.6 and up, which is larger than 64 texels in area (eg. 8x8 texels.) This condition is an error because the asset in question is wasting disk space, loading performance, video memory, and runtime performance for no benefit.
Smaller textures generate a warning, since it is frequently pointless to use a texture which contains no detail.
The error is suppressed on older (3.5 and below) content to avoid breaking older content which did not show this error when it was created. The issue is still a performance problem for older content, and should be fixed when feasible.
The most obvious fix for the error is to reduce the texture to an 8x8 square. Since the texture contains no distinguishing features, this will not affect the visual result.
To get rid of the warning entirely, you may wish to consider avoiding a uniform texture. Depending on your specific usage, a variety of alternative techniques exist, including:
- If the texture is a diffuse, consider using a m.notex material.
- If the texture is a normal, consider switching to a material which does not require a normal map.
- If the texture is used only for a small part of the asset, consider combining the texture into one of the other textures used in the asset.
- If the texture is used for a large part or all of the asset, consider whether you can provide a more meaningful texture. Uniform-color textures typically produce an unrealistic visual result for most uses.
While it is possible to avoid this error by simply introducing a minor variation into the texture, it is strongly recommended that you avoid this approach: you are simply hiding the issue from validation rather than fixing it. The performance issues will remain.