Fix: set glDepthMask false for add and multiply blend modes (#1769)
Fix: set glDepthMask false for add and multiply blend modes (#1769)


cleeus/tangram-es,cleeus/tangram-es,cleeus/tangram-es,tangrams/tangram-es,tangrams/tangram-es,tangrams/tangram-es,tangrams/tangram-es,tangrams/tangram-es,tangrams/tangram-es,cleeus/tangram-es,cleeus/tangram-es,cleeus/tangram-es,tangrams/tangram-es