This document proposes a learning-based approach to improve the accuracy and robustness of cross-ratio based gaze estimation. It introduces an adaptive homography mapping method that uses both head pose variables and pupil center position as predictor variables in a quadratic regression model. This approach is trained on large amounts of simulated eye tracking data to minimize errors across different head poses and eye parameters. Experimental results show the method achieves state-of-the-art accuracy for both stationary gaze and head movements, and is robust to variations in eye features, sensor resolution, and noise.