Feature: More Bake VC colorization methods

[lfod1997]

1. Implement basic support for changeable VC calculation methods
2. Adds 3 new colorization: grayscale (linear), grayscale (square root) and fixed-point non-color

Motivation

I'm using the addon to calculate TD and bake into VC, so I can use that data in the game engine. Currently the color is calculated with a fixed method that maps the calculated value to a hue (utils.Value_To_Color), which I believe is perfect for visualization, but not quite suitable for real-time applications as decoding the mapped color involves RGB to HSV transformation.

Contents

I'm making this PR so the VC calculation ("colorization") method can be chosen from a range of methods. This involves adding one property (props.TD_Addon_Props.bake_vc_colorization) and minor logic tweaks. Original work (the value-to-hue method) is not changed in any way and has become the default.

3 more colorization methods are also implemented:

Grayscale (Linear), calculated values are mapped to the colors' brightness:

Grayscale (Square Root), calculated values are first taken the square root of, then mapped to the colors' brightness:

Normalized 24-Bit Fixed-Point (RGB8), which bakes values directly into VC; offers higher precision than grayscale methods, at the cost of readability and slightly heavier decoding:

Calculated values are normalized and converted to 24-bit fixed-point numbers, then bitwise-split into 3 channels and converted to floating-point RGB colors, resulting in non-color RGB values in the final VC.

Data can be recovered with expression:

((round(R * 255.0) << 16) + (round(G * 255.0) << 8) + round(B * 255.0)) / float(0xffffff)

, which evaluates to the normalized value. To retrieve the original, unnormalized value, users will need to scale back using the Min and Max values, which the addon offers.

[mrven]

@lfod1997, could you clarify the use cases for normalized 24-bit fixed-point format (RGB8)? I'm wondering if it's broadly useful enough to include.

[mrven]

And one more thing - this modes isn't compatible with current checker material because it uses "Color" blend mode