pbr1.c

#ifdef HAS_METALROUGHNESSMAP
    // Roughness is stored in the 'g' channel, metallic is stored in the 'b' channel.
    // This layout intentionally reserves the 'r' channel for (optional) occlusion map data
    float4 mrSample = metallicRoughnessTexture.Sample(metallicRoughnessSampler, input.texcoord);

    perceptualRoughness = mrSample.g * perceptualRoughness;
    metallic = mrSample.b * metallic;
#endif