1. A method for interfacing with computer executable shader code, comprising: accepting, through a ray emit call, definition data for a parent ray and an association of the parent ray to a pixel of a 2-D image to be rendered from a 3-D scene composed of objects; selecting a shader based on an intersection testing result for the parent ray; accepting one or more child rays from the selected shader through the ray emit call during execution of the selected shader; accepting through the ray emit call additional data to be associated with the one or more child rays; continuing the pixel association with each of the child rays; selecting one or more shaders based on intersection testing results obtained for at least some of the child rays; interpreting the additional data associated with the one or more child rays as a reference to executable computer code; and modifying behavior of the selected one or more shaders by executing the referenced executable computer code.