procedural-3d-engine/shaders/slang/pbrtexture/skybox.slang
2025-05-04 13:31:14 +02:00

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/* Copyright (c) 2025, Sascha Willems
*
* SPDX-License-Identifier: MIT
*
*/
struct VSInput
{
float3 Pos;
float3 Normal;
float2 UV;
};
struct VSOutput
{
float4 Pos : SV_POSITION;
float3 UVW;
};
struct UBO
{
float4x4 projection;
float4x4 model;
};
ConstantBuffer<UBO> ubo;
struct UBOParams {
float4 lights[4];
float exposure;
float gamma;
};
ConstantBuffer<UBOParams> uboParams;
SamplerCube samplerEnv;
// From http://filmicworlds.com/blog/filmic-tonemapping-operators/
float3 Uncharted2Tonemap(float3 color)
{
float A = 0.15;
float B = 0.50;
float C = 0.10;
float D = 0.20;
float E = 0.02;
float F = 0.30;
float W = 11.2;
return ((color*(A*color+C*B)+D*E)/(color*(A*color+B)+D*F))-E/F;
}
[shader("vertex")]
VSOutput vertexMain(VSInput input)
{
VSOutput output;
output.UVW = input.Pos;
output.Pos = mul(ubo.projection, mul(ubo.model, float4(input.Pos.xyz, 1.0)));
return output;
}
[shader("fragment")]
float4 fragmentMain(VSOutput input)
{
float3 color = samplerEnv.Sample(input.UVW).rgb;
// Tone mapping
color = Uncharted2Tonemap(color * uboParams.exposure);
color = color * (1.0f / Uncharted2Tonemap((11.2f).xxx));
// Gamma correction
color = pow(color, (1.0f / uboParams.gamma).xxx);
return float4(color, 1.0);
}