/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */

#define PROVISIONAL_TONEMAP_GAMMA 2.4

float4 ApplyProvisionalTonemap(float4 color)
{
    // Provisional tone mapping will be applied using Reinhard, then applying gamma to handle the color in perceptual color space.
    float3 toneMappedColor = color.xyz / (1.0 + color.xyz);
    return float4(pow(toneMappedColor, 1.0 / PROVISIONAL_TONEMAP_GAMMA), color.w);
}

float4 ApplyInverseProvisionalTonemap(float4 color)
{
    // This is inverse function of provisional tone mapping.
    float3 linearValue = pow(color.xyz, PROVISIONAL_TONEMAP_GAMMA);
    return float4(linearValue / (1.0 - linearValue), color.w);
}