GLTFLoader: Revert usage of computeTangents().

examples/js/loaders/GLTFLoader.js

@@ -3243,21 +3243,6 @@ THREE.GLTFLoader = ( function () {
 						? new THREE.SkinnedMesh( geometry, material )
 						: new THREE.Mesh( geometry, material );
 
-					// Fix double sided rendered models on certain mobile devices, see https://github.com/mrdoob/three.js/issues/20997#issuecomment-756082184
-
-					if ( material.isMeshStandardMaterial === true &&
-						material.side === THREE.DoubleSide &&
-						geometry.getIndex() !== null &&
-						geometry.hasAttribute( 'position' ) === true &&
-						geometry.hasAttribute( 'normal' ) === true &&
-						geometry.hasAttribute( 'uv' ) === true &&
-						geometry.hasAttribute( 'tangent' ) === false ) {
-
-						geometry.computeTangents();
-						material.vertexTangents = true;
-
-					}
-
 					if ( mesh.isSkinnedMesh === true && ! mesh.geometry.attributes.skinWeight.normalized ) {
 
 						// we normalize floating point skin weight array to fix malformed assets (see #15319)

examples/jsm/loaders/GLTFLoader.js

@@ -3308,21 +3308,6 @@ var GLTFLoader = ( function () {
 						? new SkinnedMesh( geometry, material )
 						: new Mesh( geometry, material );
 
-					// Fix double sided rendered models on certain mobile devices, see https://github.com/mrdoob/three.js/issues/20997#issuecomment-756082184
-
-					if ( material.isMeshStandardMaterial === true &&
-						material.side === DoubleSide &&
-						geometry.getIndex() !== null &&
-						geometry.hasAttribute( 'position' ) === true &&
-						geometry.hasAttribute( 'normal' ) === true &&
-						geometry.hasAttribute( 'uv' ) === true &&
-						geometry.hasAttribute( 'tangent' ) === false ) {
-
-						geometry.computeTangents();
-						material.vertexTangents = true;
-
-					}
-
 					if ( mesh.isSkinnedMesh === true && ! mesh.geometry.attributes.skinWeight.normalized ) {
 
 						// we normalize floating point skin weight array to fix malformed assets (see #15319)