Note these are integer values between 0 and 3590, hence the struct IPoint. Note this represents the degrees in tenths of a degree. Currently these are just integers r,g,b for the red, green and blue components of the surface color. This is where you retrieve the values for the color to draw the object. These values are computed from the ambient color associated with the object through attaching a particular material to it.
Ambient color is just the color an object appears in the abscence of any light sources.
As we currently are not using any light sources in our scene the objects are displayed in their ambient color only. In future assignments we will implement a lighting model which will use other fields associated with each material. The next object is just a pointer to the next object in the scene. The loop in userCode.c has a function which returns this object so that you can easily traverse the list of objects to be displayed. The reason we use this function is that the next object pointer should not be referenced directly.