Made `#define TEXTURE_LOD_EXT` more precise

src/renderers/webgl/WebGLProgram.js

@@ -525,7 +525,7 @@ function WebGLProgram( renderer, extensions, code, material, shader, parameters,
 			parameters.logarithmicDepthBuffer ? '#define USE_LOGDEPTHBUF' : '',
 			parameters.logarithmicDepthBuffer && ( capabilities.isWebGL2 || extensions.get( 'EXT_frag_depth' ) ) ? '#define USE_LOGDEPTHBUF_EXT' : '',
 
-			( ( ! material.extensions || material.extensions.shaderTextureLOD ) || parameters.envMap ) && ( capabilities.isWebGL2 || extensions.get( 'EXT_shader_texture_lod' ) ) ? '#define TEXTURE_LOD_EXT' : '',
+			( ( material.extensions ? material.extensions.shaderTextureLOD : false ) || parameters.envMap ) && ( capabilities.isWebGL2 || extensions.get( 'EXT_shader_texture_lod' ) ) ? '#define TEXTURE_LOD_EXT' : '',
 
 			'uniform mat4 viewMatrix;',
 			'uniform vec3 cameraPosition;',