GLSL for POPs in TouchDesigner: Lesson 4 (GLSL Copy POP + Phyllotaxis)

In this lesson of GLSL in POPs, we explore the GLSL Copy POP by building a procedural phyllotaxis pattern — the same spiral structure found in sunflowers and pinecones. You’ll learn how to use GLSL to position and color thousands of copies directly on the GPU, using the golden angle and square-root radius formula to generate natural, mathematically perfect arrangements.

This lesson is a deep dive into how the Copy POP works under the hood, how to index and transform copies with custom GLSL logic, and how to animate and extend these systems to 3D.

📌 Key Topics Covered:
✅ What the GLSL Copy POP does and how it differs from the standard GLSL POP
✅ Understanding copy indexing and per-instance attributes
✅ Implementing the golden angle spiral (phyllotaxis) in GLSL
✅ Generating and coloring procedural copies on the GPU
✅ Extending the technique to 3D and animating phyllotactic forms

🎨 Exercises & Challenges:
🛠️ Add Z-axis offsets to form a 3D spiral pattern
🛠️ Animate the golden angle or scale to create evolving phyllotaxis
🛠️ Map color to radius or index for dynamic variation

🔗 Further Learning:

TouchDesigner Docs: https://docs.derivative.ca

Writing GLSL POPs: https://derivative.ca/UserGuide/Experimental:Write_GLSL_POPs

Mastering GLSL in TouchDesigner (Intro Course): https://www.patreon.com/collection/1268383?view=expanded

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🔹 Portfolio: https://www.lakeheckaman.com

🔹 Instagram: https://instagram.com/lake_heckaman

00:00 – Start
00:01 – Introduction
02:07 – Phyllotaxis Overview
04:10 – Phyllotaxis algorithm formulas
07:11 – Touchdesigner network overview
09:54 – Begin to write GLSL code for phyllotaxis
18:27 – Full Code