Computer art for the Tektronix 4052.(part 5)Joe Jacobson.

Computer Art For The Tektronix 4052

In this article I discuss my Since Power program. This routine is similar in structure to the polar coordinate programs I have presented in recent issues of Creative Computing. The radius is computed as the weighted sum of powers of sinusoids, or as a root of the absolute value of the weighted sum (depending on the values selected for parameters U and P).

The use of powers of sinusoids was suggested by a fellow computer artist and co-worker, Joel Wexler, and is also a natural extension of the Sine Product program (Creative Computing, May 1983). As in the Sine Product program, Sine Power incorporates automatic scaling.

The program prompts the user to enter certain input parameters from the keyboard. The parameters M and N are exponents (powers) of the sinusoids. K and L are angular frequency coefficients in the arguments of the sinusoids. S and T are amplitude weights of the sinusoidal terms. Q is the exponent of the absolute value; if Q has a value between 0 and 1, the result is a root. D is the increment in radius between successive angular sweeps. G is the increment in angle within a sweep.

If you want a list of input parameter values at the bottom of the picture, set

T1 equal to 1. After the plot is complete, with the parameter list, clear the screen and hit RETURN. You will get a "clean' plot (without the parameter list). If you don't want a parameter list at all, set T1 equal to 2.

Table 1 lists ranges of values that seem to give good results. Some values outside these intervals may also work well.

In a future issue of Creative Computing I will describe a completely different type of polar coordinate computer art program.

Table: Suggested Parameter Values.