Points on a circle's circumference are computed from center, radius, and angle using sin/cos

To draw a circle (or any circular form) without Processing’s ellipse(), use the fundamental trigonometric relationship: for a given angle, the x offset from center is radius × cos(angle) and the y offset is radius × sin(angle). By iterating angle from 0 to 360 degrees (converted to radians) and connecting successive points, you reconstruct the circle. This rotational drawing approach gives full control over how the circle is drawn — enabling you to vary the radius, angle step, or path at each iteration. It naturally extends to spirals (increment the radius as the angle increases) and noisy circles (add Perlin noise to the radius). Radians = degrees × π/180; Processing provides radians() and degrees() conversion functions.

Examples

Basic circle: x = centX + radius * cos(radians(ang)); y = centY + radius * sin(radians(ang)); Spiral: add radius += 0.5; inside the loop. Noisy circle: thisRadius = radius + (noise(radiusNoise) * 200) - 100;

Assessment

Using only sin/cos (no ellipse()), write pseudocode to draw an octagon centered at (250, 150) with radius 100, and explain why angle steps of 45 degrees produce 8 points.