1. A method for determining a variability value of each calculation in a shader, wherein the shader includes a plurality of calculations and receives a plurality of input parameters varying in two or more dimensions, the method comprising: obtaining, with one or more processors associated with one or more computer systems, a representation of variability; selecting, with the one or more processors associated with the one or more computer systems, a first calculation from the plurality of calculations, wherein the first calculation comprises a first input parameter and a second input parameter; obtaining, with the one or more processors associated with the one or more computer systems, a first variability value for at least two dimensions of the first input parameter; obtaining, with the one or more processors associated with the one or more computer systems, a second variability value for at least two dimensions of the second input parameter; determining, with the one or more processors associated with the one or more computer systems, a third variability value of the first calculation based on the first variability value, the second variability value, and the representation of variability; and generating, with the one or more processors associated with the one or more computer systems, information assigning the third variability value to the first calculation.