gpu-curtains/dist/esm/core/shaders/chunks/fragment/body/get-PBR-direct-contribution.mjs

gpu-curtains is a 3D WebGPU rendering engine. It can be used as a standalone 3D engine, but also includes extra classes focused on mapping 3d objects to DOM elements; It allows users to synchronize values such as position, sizing, or scale between them.

//#region src/core/shaders/chunks/fragment/body/get-PBR-direct-contribution.ts
/**
* Get the PBR direct light contribution.
*
* @param parameters - Parameters used to create the shader chunk.
* @param parameters.extensionsUsed - {@link PBRFragmentShaderInputParams.extensionsUsed | extensionsUsed} to check if anisotropy is enabled.
* @returns - The PBR direct light contribution, accounting for anisotropy, sheen and clearcoat contributions.
*/
const getPBRDirectContribution = ({ extensionsUsed = [], environmentMap = null } = {}) => {
	let pbrDirect = `
    let NdotL: f32 = saturate(dot(normal, directLight.direction));
    var irradiance: vec3f = NdotL * directLight.color;`;
	if (extensionsUsed.includes("KHR_materials_clearcoat")) pbrDirect += `
    clearcoatSpecularDirect += getPBRDirectClearcoat(clearcoatNormal, viewDirection, clearcoatF0, clearcoatF90, clearcoatRoughness, directLight);`;
	if (extensionsUsed.includes("KHR_materials_sheen")) {
		pbrDirect += `
    sheenSpecularDirect += irradiance * BRDF_Sheen(directLight.direction, viewDirection, normal, sheenColor, sheenRoughness);`;
		if (environmentMap && environmentMap.lutTexture) pbrDirect += `
    let sheenAlbedoV: f32 = getBRDFCharlie(
      normal,
      viewDirection,
      sheenRoughness,
      ${environmentMap.sampler.name},
      ${environmentMap.lutTexture.options.name}
    );
    
    let sheenAlbedoL: f32 = getBRDFCharlie(
      normal,
      directLight.direction,
      sheenRoughness,
      ${environmentMap.sampler.name},
      ${environmentMap.lutTexture.options.name}
    );`;
		else pbrDirect += `
    let sheenAlbedoV: f32 = getSheenAlbedoScaleApprox(
      normal,
      viewDirection,
      sheenRoughness
    );
    
    let sheenAlbedoL: f32 = getSheenAlbedoScaleApprox(
      normal,
      directLight.direction,
      sheenRoughness
    );`;
		pbrDirect += `
    let sheenEnergyComp: f32 = 1.0 - max3( sheenColor ) * max( sheenAlbedoV, sheenAlbedoL );
 		irradiance *= sheenEnergyComp;`;
	}
	if (environmentMap && environmentMap.lutTexture) pbrDirect += `
    // Precomputed DFG values for view and light directions from LUT
    let dfgDirect: DFGDirect = DFGDirectFromLUT(
      normal,
      viewDirection,
      directLight.direction,
      roughness,
      ${environmentMap.sampler.name},
      ${environmentMap.lutTexture.options.name},
    );
    `;
	else pbrDirect += `
    // Precomputed DFG values for view and light directions from approximation
    let dfgDirect: DFGDirect = DFGDirectApprox(
      normal,
      viewDirection,
      directLight.direction,
      roughness,
    );
    `;
	if (extensionsUsed.includes("KHR_materials_anisotropy")) pbrDirect += `
    var lightContribution: LightContribution = getPBRDirectAnisotropic(
      normal,
      viewDirection,
      NdotL,
      irradiance,
      dfgDirect,
      diffuseContribution,
      specularF90,
      specularColorBlended,
      roughness,
      iridescenceFresnel,
      iridescence,
      alphaT,
      anisotropyT,
      anisotropyB,
      directLight
    );`;
	else pbrDirect += `
    var lightContribution: LightContribution = getPBRDirect(
      normal,
      viewDirection,
      NdotL,
      irradiance,
      dfgDirect,
      diffuseContribution,
      specularF90,
      specularColorBlended,
      roughness,
      iridescenceFresnel,
      iridescence,
      directLight
    );`;
	if (extensionsUsed.includes("KHR_materials_diffuse_transmission")) {
		pbrDirect += `
    lightContribution.diffuse = lightContribution.diffuse * (1.0 - diffuseTransmission);
    let diffuseNdotL: f32 = saturate(dot(-1.0 * normal, directLight.direction));
    var lightDiffuseTransmission: vec3f = directLight.color * diffuseNdotL * BRDF_Lambert(diffuseTransmissionContribution);`;
		if (extensionsUsed.includes("KHR_materials_volume")) pbrDirect += `
    lightDiffuseTransmission *= volumeAttenuation(diffuseTransmissionThickness, attenuationColor, attenuationDistance);
    `;
		pbrDirect += `
    // lightDiffuseTransmission *= 1.0 - singleVolumeScatter;
    lightDiffuseTransmission *= singleVolumeScatter;
    lightContribution.diffuse += lightDiffuseTransmission * diffuseTransmission;
    `;
	}
	pbrDirect += `
    reflectedLight.directDiffuse += lightContribution.diffuse;
    reflectedLight.directSpecular += lightContribution.specular;
  `;
	return pbrDirect;
};
//#endregion
export { getPBRDirectContribution };