Bending pixels to your will | Ian Shephard | NZGDC 2025

Bending pixels to your will | Ian Shephard | NZGDC 2025

by Ian Shephard

Applied Sciences & Engineering Computing & Cybersecurity UMComputer programmingUMKGames development and programming
🎙 Ian Shephard 👥 1K 📅 October 12, 2025 ⏱ 51 min 👁 218 📄 tutorial 🧭 2026-08-16
Available in: English (current) Français

Keywords

shaderUVgradientnoisesine wave

Summary

In this talk from NZGDC 2025, Ian Shephard, a generalist programmer with two decades of experience, introduces shaders to a broad audience, emphasizing a codeless approach using shader graph editors in Unity, Unreal, and Godot. He begins by defining shaders as GPU-executed code that transforms data, covering vertex, geometry, fragment, and compute shaders, but focuses on vertex and fragment shaders. The core of the talk explains how colors are represented as 0-1 values and how mathematical operations like multiplication and addition can push these values out of range, leading to clipping. He demonstrates practical applications such as creating a simple fog effect using distance and a lerp function. He then delves into UV coordinates, explaining how gradients can be generated procedurally to save texture memory, and shows how to create masks and shapes like leaves using mathematical functions. Noise functions are introduced as a way to add randomness, with texture-based noise being performance-friendly. He also covers sine and cosine waves for smooth oscillations, demonstrating how to remap their output to 0-1 range and use them for animations. Throughout, he emphasizes performance considerations and the balance between memory savings and computational cost. The talk concludes with tips on using existing buffers and a Q&A session.

204 words

Critical Evaluation

Value of the Information & Strength of the Argument

The talk provides valuable, practical knowledge for game developers and technical artists, offering engine-independent techniques that can be applied across major engines. The argumentation is solid, built on clear explanations of fundamental concepts like color ranges and UV mapping, and reinforced with visual examples. The speaker’s experience lends credibility, and he effectively communicates complex ideas in an accessible manner. The emphasis on performance and memory trade-offs is particularly valuable for real-world development.

Scientific Rigor, Source Quality, Title Accuracy

The talk demonstrates scientific rigor by grounding explanations in established mathematical and programming principles. While no formal academic sources are cited, the speaker references the Shader Forge documentation as a resource, which is a reputable source in the shader community. The title accurately reflects the content, which focuses on manipulating pixels through shaders. The talk is well-structured and the techniques presented are reproducible, enhancing its reliability.

153 words

Title / Content Match

The title accurately reflects the content, which focuses on manipulating pixels through shaders, with a playful tone.

Quality & Reliability

8/10

The speaker has 20 years of programming experience and 10 in game development, providing practical, engine-agnostic knowledge. The content is well-structured and based on established shader programming concepts, though it lacks formal citations or references to academic sources.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Concurring Sources

  • Shader Forge Documentation — Provides visual examples of blend modes and gradient generation, aligning with the talk's techniques.

Contribution & Novelties

The talk offers a comprehensive, engine-agnostic introduction to shader programming, focusing on visual shader graphs. It provides practical techniques for generating gradients, masks, and effects without textures, which can be immediately applied in Unity, Unreal, and Godot. The emphasis on performance and memory trade-offs is particularly valuable for developers targeting limited hardware.

Pour aller plus loin :

  • Shader Graph in Unity — Official documentation for Unity’s Shader Graph, covering nodes and workflows.
  • Unreal Engine Material Editor — Official documentation for Unreal’s Material Editor, including material nodes and functions.
  • Godot Visual Shaders — Official documentation for Godot’s Visual Shader editor.
  • HLSL Shader Programming — Microsoft’s HLSL reference for those interested in code-based shaders.

112 words

Radar Profile

The radar profile shows high scores in information quantity, quality, and reliability, with a slightly lower technical level, indicating a well-balanced talk that is both informative and accessible. The strong performance in all areas suggests a comprehensive and trustworthy presentation.

Reliability 8/10