Three.js: the error of using lightmap

[trymoremore]

i use the lightmap to add shadow to the model,but the result is error,
the setting of js :
"mapLight" : "Q4.jpg",
and the setting of html:
for ( var i = 0; i < materials.length; i ++ ) {
materials[ i ].lightMapIntensity =0.75;
}
geometry.faceVertexUvs[ 1 ] = geometry.faceVertexUvs[ 0 ];
the result:

i set down the lightMapIntensity,the result is normal ,but the shadow is disapperar:

[WestLangley]

Lightmaps in three.js are treated as a source of light. They are purely additive to the total indirect diffuse light; they do not darken or attenuate light.

Only ambient occlusion maps (aoMap) darken; they attenuate total indirect diffuse light.