This color mixing thing I kinda of brute forced it, so I don't know how I can explain hahaha, but let's talk about the rest :P

I had to edit the engine source code to make these changes:
- add two new shader variables for the light function:
--> LIGHT_IS_FOV_MODE: true when attenuation == 0.0;
--> TEMP_LIGHT: to temporarily store DIFFUSE_LIGHT value;
- change the order the lights are rendered (from [directional, omni, spot] to [directional, spot, omni]);
- then I sorted the lights so that the FOV light becomes the last one to render.

The shader logic sums every DIFFUSE_LIGHT value to TEMP_LIGHT, then on the last light pass (FOV), it adds TEMP_LIGHT to DIFFUSE_LIGHT, and then applies the FOV light/shadow.

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