ACES to ADX transform

[scottdyer]

ACES to ADX transform should be examined for possible updates as suggested in this ACES Central post

There is also a clamp in the ADX transforms (not new to 1.2):

lines around 71 in ACEScsc.ADX10_to_ACES.ctl and ACEScsc.ADX16_to_ACES.ctl

float logE[3];
if ( cid[0] <= 0.6) logE[0] = interpolate1D( LUT_1D, cid[0]);
if ( cid[1] <= 0.6) logE[1] = interpolate1D( LUT_1D, cid[1]);
if ( cid[2] <= 0.6) logE[2] = interpolate1D( LUT_1D, cid[2]);

interpolate1D is defined to clamp outside the range and so there should probably be linear extrapolation added for the lower portion of values so that values below ‘95’ (-0.19) don’t get clamped during conversion. similar to how this values above 0.6 are handled.

There are potential issues with the following pow( 10 , logE[*] ) calls, but that is a more involved discussion relating to noise, that doesn’t have as obvious a potential fix.

[KevinJW]

Interactive demo ... https://www.desmos.com/calculator/hdiujynasa

There was also a suggestion to formulate the table as an exponential function, but I haven't fitted that yet,