fn hue_shader_for(time: f32) -> [f32; 4]Expand description
Time-driven RGB tint MD2 cycles through each frame. Three oscillators
with mutually-prime periods produce a slow rainbow rotation that
never repeats (rationals on the unit circle); presets that multiply
ret * hue_shader get the rainbow rotation MD2 is tuned for, while
presets that ignore it keep their authored colour palette because
the per-channel output stays in [0, 1] and floats around ~0.5.
.w is reserved for a future per-corner mix factor.