Hi @lucylu and thanks for getting in touch. If your intention is to develop software for interactive or gaming applications, then for your eye tracke model, we would recommend you check out the Tobii Interaction Library API or the Tobii Stream Engine which you can download at the following locations:
Therein, there are several sample applications that can help you get up and running quickly.
Please bear in mind however, that using the 4C tracker for analysis or research purposes is expressly prohibited by the end user licence agreement.
Do let us know if you have any further questions. Best Wishes.