cnq3/code/renderer/hlsl/post_inverse_gamma.hlsl

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/*
===========================================================================
Copyright (C) 2023 Gian 'myT' Schellenbaum
This file is part of Challenge Quake 3 (CNQ3).
Challenge Quake 3 is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
Challenge Quake 3 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Challenge Quake 3. If not, see <https://www.gnu.org/licenses/>.
===========================================================================
*/
// post-processing: moves from gamma to linear space
struct VOut
{
float4 position : SV_Position;
float2 texCoords : TEXCOORD0;
};
#if VERTEX_SHADER
VOut vs(uint id : SV_VertexID)
{
VOut output;
output.position.x = (float)(id / 2) * 4.0 - 1.0;
output.position.y = (float)(id % 2) * 4.0 - 1.0;
output.position.z = 0.0;
output.position.w = 1.0;
output.texCoords.x = (float)(id / 2) * 2.0;
output.texCoords.y = 1.0 - (float)(id % 2) * 2.0;
return output;
}
#endif
#if PIXEL_SHADER
// X3571: pow(f, e) won't work if f is negative
#pragma warning(disable : 3571)
cbuffer RootConstants
{
float gamma;
float invBrightness;
};
Texture2D texture0 : register(t0);
SamplerState sampler0 : register(s0);
float4 ps(VOut input) : SV_Target
{
float3 raw = texture0.Sample(sampler0, input.texCoords).rgb;
float3 base = saturate(raw); // can have negative values in the float render target
float3 linearSpace = pow(base * invBrightness, gamma);
return float4(linearSpace, 1.0f);
}
#endif