import { default } from "https://deno.land/x/threejs_4_deno@v121/src/renderers/shaders/ShaderChunk/normal_fragment_begin.glsl.js";
type
`
#ifdef FLAT_SHADED
// Workaround for Adreno/Nexus5 not able able to do dFdx( vViewPosition ) ...
vec3 fdx = vec3( dFdx( vViewPosition.x ), dFdx( vViewPosition.y ), dFdx( vViewPosition.z ) );
vec3 fdy = vec3( dFdy( vViewPosition.x ), dFdy( vViewPosition.y ), dFdy( vViewPosition.z ) );
vec3 normal = normalize( cross( fdx, fdy ) );
#else
vec3 normal = normalize( vNormal );
#ifdef DOUBLE_SIDED
normal = normal * ( float( gl_FrontFacing ) * 2.0 - 1.0 );
#endif
#ifdef USE_TANGENT
vec3 tangent = normalize( vTangent );
vec3 bitangent = normalize( vBitangent );
#ifdef DOUBLE_SIDED
tangent = tangent * ( float( gl_FrontFacing ) * 2.0 - 1.0 );
bitangent = bitangent * ( float( gl_FrontFacing ) * 2.0 - 1.0 );
#endif
#if defined( TANGENTSPACE_NORMALMAP ) || defined( USE_CLEARCOAT_NORMALMAP )
mat3 vTBN = mat3( tangent, bitangent, normal );
#endif
#endif
#endif
// non perturbed normal for clearcoat among others
vec3 geometryNormal = normal;
`