// <ACEStransformID>urn:ampas:aces:transformId:v1.5:RRTODT.Academy.Rec2020_1000nits_15nits_HLG.a1.1.0</ACEStransformID>

// <ACESuserName>ACES 1.0 Output - Rec.2020 HLG (1000 nits)</ACESuserName>

//

// Output Transform - Rec.2020 (1000 cd/m^2)

// Summary :

// This transform maps ACES onto a Rec.2020 HLG HDR display calibrated

// to a D65 white point at 1000 cd/m^2. The assumed observer adapted white is

// D65, and the viewing environment is that of a dark surround. Mid-gray

// luminance is targeted at 15 cd/m^2.

//

// NOTE :

// The parameterized "Output Transform" function used as basis for this

// transform includes a parameter labeled "SURROUND". However, as noted in

// "ACESlib.OutputTransforms.ctl", this sub-module is currently a "placeholder"

// and as such currently only supports a rendering intended for dark surround

// environments. While it is planned for future releases to fully activate the

// this module and provide adjustment for dark/dim/normal surrounds, setting

// SURROUND equal to either dim or normal will have no effect at this time.

//

// That being said, these Output Transforms have been used successfully on

// major feature and television projects when mastering for home HDR where a

// dim surround environment is assumed. Based on that, these transforms are

// considered adequate for use for dim surround mastering, although, as always,

// creative adjustments to contrast and saturation may be desirable and should

// be saved as a "trim pass."

// Device Primaries :

// Primaries are those specified in Rec. ITU-R BT.2020

// CIE 1931 chromaticities: x y Y

// Red: 0.708 0.292

// Green: 0.17 0.797

// Blue: 0.131 0.046

// White: 0.3127 0.329 1000 cd/m^2

// 18% Gray: 0.3127 0.329 15 cd/m^2

// Display EOTF :

// The reference electro-optical transfer function specified in Table 5 of

// ITU-R BT.2100 (HLG)

// Assumed observer adapted white point:

// CIE 1931 chromaticities: x y

// 0.3127 0.329

// Viewing Environment:

// Environment specified in SMPTE RP 431-2-2007

import "ACESlib.Utilities";

import "ACESlib.OutputTransforms";

// Support for HLG in ACES is tricky, since HLG is "scene-referred" and ACES

// Output transforms produce display-referred output. ACES supports HLG at

// 1000 nits by converting the ST.2084 output to HLG using the method specified

// in Section 7 of ITU-R BT.2390-0.

const float Y_MIN = 0.0001; // black luminance (cd/m^2)

const float Y_MID = 15.0; // mid-point luminance (cd/m^2)

const float Y_MAX = 1000.0; // peak white luminance (cd/m^2)

const Chromaticities DISPLAY_PRI = REC2020_PRI; // encoding primaries (device setup)

const Chromaticities LIMITING_PRI = REC2020_PRI;// limiting primaries

const int EOTF = 5; // 0: ST-2084 (PQ)

// 1: BT.1886 (Rec.709/2020 settings)

// 2: sRGB (mon_curve w/ presets)

// 3: gamma 2.6

// 4: linear (no EOTF)

// 5: HLG

const int SURROUND = 0; // 0: dark ( NOTE: this is the only active setting! )

// 1: dim ( *inactive* - selecting this will have no effect )

// 2: normal ( *inactive* - selecting this will have no effect )

const bool STRETCH_BLACK = true; // stretch black luminance to a PQ code value of 0

const bool D60_SIM = false;

const bool LEGAL_RANGE = false;

void main

input varying float rIn,

input varying float gIn,

input varying float bIn,

input varying float aIn,

output varying float rOut,

output varying float gOut,

output varying float bOut,

output varying float aOut

float aces[3] = {rIn, gIn, bIn};

float cv[3] = outputTransform( aces, Y_MIN,

Y_MID,

Y_MAX,

DISPLAY_PRI,

LIMITING_PRI,

EOTF,

SURROUND,

STRETCH_BLACK,

D60_SIM,

LEGAL_RANGE );

rOut = cv[0];

gOut = cv[1];

bOut = cv[2];

aOut = aIn;