three.js/src/renderers/shaders/ShaderChunk/gradientmap_pars_fragment.glsl.js

export default `
#ifdef TOON

	uniform sampler2D gradientMap;

	vec3 getGradientIrradiance( vec3 normal, vec3 lightDirection ) {

		// dotNL will be from -1.0 to 1.0
		float dotNL = dot( normal, lightDirection );
		vec2 coord = vec2( dotNL * 0.5 + 0.5, 0.0 );

		#ifdef USE_GRADIENTMAP

			return texture2D( gradientMap, coord ).rgb;

		#else

			return ( coord.x < 0.7 ) ? vec3( 0.7 ) : vec3( 1.0 );

		#endif


	}

#endif
`;