References: Polar Coordinates, Oscillation & Easing¶
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Polar coordinate system - Wikipedia - Two-dimensional coordinate system defined by radius and angle, including conversion formulas to Cartesian coordinates. Vital for spiral generation, radial symmetry, and circular particle rings.
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Atan2 - Wikipedia - Mathematical and computational derivation of the two-argument arctangent function, resolving quadrant ambiguities. Fundamental for calculating directional heading angles toward target points in interactive systems.
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Lissajous curve - Wikipedia - Parametric curves generated by orthogonal sinusoidal inputs with varying frequency ratios and phase shifts. Invaluable for creating intricate harmonograph patterns and oscilloscope generative sketches in p5.js.
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The Animator's Survival Kit: A Manual of Methods, Principles and Formulas for Classical, Computer, Games, Stop Motion and Internet Animators - Richard Williams - Faber and Faber - Williams formulated the foundational slow-in and slow-out easing principles, providing the classic visual timing charts that inspire computational easing curve algorithms in interactive animation.
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Foundation Actionscript 3.0 Animation: Making Things Move! - Keith Peters - Friends of ED / Apress - Peters pioneered the canonical Spring and Easing code algorithms for interactive designers, reducing complex calculus into intuitive proportional velocity formulas for interactive visual projects.
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Polar Coordinates in p5.js - The Coding Train - Visual video lesson demonstrating how radius and theta convert via
x = r * cos(theta)andy = r * sin(theta)to create spirals, orbital motion, and algorithmic flowers. -
Easing Functions Cheat Sheet - Andrey Sitnik & Ivan Solovev - Interactive visualization and mathematical formulas for quadratic, cubic, elastic, and bounce easing curves with copy-paste JavaScript snippets for smooth UI animation and motion graphics.
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Understanding atan2() and Directional Rotation - MDN Web Docs - Technical guide explaining Math.atan2 parameter order, return range in radians (-PI to PI), and practical applications for tracking mouse cursor angles accurately in graphics.
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Harmonograph and Lissajous Curve Generator - Walking Randomly - Mathematical exploration of mechanical harmonographs, phase offsets, and decay envelopes for plotting complex resonant waveforms in procedural code sketches and generative patterns.
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p5.js Trigonometric Calculations Reference - p5.js Foundation - Documentation for atan2(), angleMode(DEGREES/RADIANS), and polar math functions used to position elements radially around a center point on the interactive canvas viewport.