Unexpected wall color behavior

[boris]

For quite some time GZDoom had the ability to color single sidedef parts like Doom 64 style wall colors. That's in the GZDoom UDMF specs.

There is some behavior that I didn't expect, but it might also be user error. This is specifically about the lowercolor_*, bottomcolor_*, and useowncolors_* properties.

Here are my observations (using the middle texture as an example for clarity, top and bottom show the same behavior) for wall colors:

Properties: uppercolor_mid is not set, lowercolor_mid is set
Result: upper color is black, lower color is as expected
Comment: considering that 0 is the default for ints that technically makes sense, but 0xffffff as a default for not defined colors would probably make more sense.

Properties: uppercolor_mid is set, lowercolor_mid is not set
Result: is uses the upper color for the whole part, no gradient
Comment: this is very unexpected, and is not in line with the case above.

Properties: uppercolor_mid is set, lowercolor_mid is set
Result: gradient as expected
Comment: nothing to say, it's as expected


There also seems to be an issue with the useowncolors_* properties. They seem to default to true. The docs state "Default is using the colors from the owning sector.". From that I'd expect the default to be false. But not setting the property at all makes it use its own colors. Explicitly setting it to false will use the sector's colors.

Example WAD showing the behavior:

wall-colors.zip