Parity — whole Transmittance LUT, WGSL backend vs TSL backend
Two TransmittanceLUT instances, backend:'wgsl' and backend:'tsl', each rendered into a float target (bypassing the shipped half-float LUT storage so the diff reflects the shader math, not quantization). Max |WGSL − TSL| over all texels/channels is read back for a numeric verdict. The canvas shows the WGSL LUT (bright top-left, dark grazing bottom-right).
running…