This module adds support to index multiple view mode renderings on an entity.
Configuration
To enable the new fields returned from Solr, you need to first edit each Search server in SearchAPI config and check off "Retrieve result data from Solr".
There is very little to configuring this module. Enabling it will add a new data alteration callback in an index called "Multiple entity views". Select all the view modes in its option list for the indexed entity. When processing the data, SearchAPI will render the entity item in each view mode, storing the HTML content in Solr.
The advantage to this is that you can bypass hooking, loading, and rendering entities for data because you know they are already cached/stored in Solr. A good example of this would be a search form with search presentation(s) or entities rendered in sidebars, footers, or mobile devices.
Using this module in conjunction with Entity View Modes is highly suggested, so you can create multiple view modes on the fly via the admin UI.
How to Use
In your code, when dealing with a Solr response, there should be new fields returned. Each field will be called "search_api_viewed_" with the view mode name affixed to the end.