(ATTR|GLOBAL)_shadow_blend doesn't use material.xplane.blendRatio

[tngreene]

Correctness bug: _shadow_blend doesn't let the user set .blendRatio for shadow blend. It simply exports
ATTR_shadow_blend
with nothing after it.

X-Plane has been using the default value .5 this whole time and I guess nobody noticed or cared enough to file a bug.

[tngreene]

This would also be a good moment to make a blend mode unit test.

[kbrandwijk]

Looking into this, .blendRatio is specifically defined as 'Alpha cutoff ratio'. I'm not sure, based on the name and description of that property, if blendRatio should be used, or a separate shadowBlendRatio should be introduced?

[kbrandwijk]

Looking further, this decision would also impact the converter (see #455)

[tngreene]

I think we should reuse blendRatio instead of making a new property (we are extremely new property averse since they are very hard to cleanly remove).

• The ratio in ATTR_no_blend <ratio> and ATTR_shadow_blend <ratio> represent the same range of values (0.0-1.0)`
• Artists are very unlikely to switch Blend Mode often and then re-assign blendRatio
• If I'm wrong and they do switch Blend Modes a lot, we can add this in later, and use the updater to copy to "Blend Mode is Shadow Blend + blendRatio" -> shadowBlendRatio

Another change, capitalize C and R in Alpha Cutoff Ratio. The name is good but we'll need to change the description based on Shadow Blend vs Alpha Cutoff.

[kbrandwijk]

I agree that they are so close together in functionality and meaning, and the blend modes being mutually exclusive of course, so reusing the prop makes sense indeed.

However, I could find a way to change the text that is shown in the textbox (that's just a parameter when you add it to the panel), but I couldn't figure out how to dynamically change the description (shown in the tooltip).

[tngreene]

I could have sworn you could have changed the tooltip. I guess not! Strange.

I care more about not changing the data model than not changing the UI.

the tool tip can be something general about how a Blend Ratio controls the output and we can have different labels beneath with the description we want. Will decide later, but I'm welcome to suggestions

[tngreene]

And, very small reminder to myself in the future, there's a TODO comment in xplane_249_material_converter that is set to be removed after this is finished.