OPERATION STARFALL

Project Status: Completed
Project Type: Professional
Project Duration: 4 weeks
Software Used: Unity 2022.3
Languages Used: C#
Team: 2 Devs
Primary Role(s):Shader Programmer

About Feature

Radial Stamina was our replacement for the old stamina system in Operation Starfall.
Built using ShaderGraph, this was my first hands-on shader project.
Developed collaboratively with J5X.

neonorigins.com

My Features

Intro

Creating this stamina system meant stepping out of my comfort zone and diving into shaders. Instead of a code-only approach, I explored how to build gameplay features through visual scripting. I pair-programmed parts of the stamina logic with another developer, while focusing on ShaderGraph with pointers from both the art and technical directors.

Gif of the Radial

Image 1

It was inspired by the stamina radial in Zelda: BotW.


Development

At first, grasping how shaders manipulate graphics was a challenge. Trial, error, and lots of debugging slowly revealed how to control colors, masks, and timing. Eventually, the system clicked: it felt less like abstract math and more like designing a visual feature. Seeing the radial animate correctly in-game was a rewarding payoff for the effort.

Functions from the script.

Image 1

In the snippet above you can see the code of when the stamina bar is depleted and how long it takes to regenerate the stamina back.

How the radial would look in game

Image 1

As seen above the stamina radial goes empty when running and when it hits 0, it plays an animations and then regenerates the stamina back over time.


Conclusion

By leveraging shaders, we created a stamina system that was both functional and visually aligned with the game’s style. For me, this feature was a turning point — from seeing shaders as intimidating, to recognizing them as a powerful tool for gameplay and atmosphere.

Full Shader Graph Overview:

Image 1

This graph uses a radial mask to visualize stamina, with time-based fade logic and dynamic alpha blending based on gameplay inputs.


ShaderGraph Breakdown

The Shader is split into three key sections, each responsible for a part of the stamina ring's visual behavior.

Stamina Fade Logic - Top

This section manages fade-in and fade-out behavior based on stamina events.

Fade-In:

  • • Subtract StaminaUpdateTime from Time to get the time since the last update.
  • • Apply Sign and Saturate to convert it into a clean 0–1 fade-in value.
  • • This ensures the bar only appears after stamina changes.

Fade-Out:

  • • Subtract Time from (StaminaUpdateTime + MaxStaminaTime + FadeTime).
  • • Divide the result by FadeTime, then clamp using Sign and Saturate.
  • • This value decreases over time, fading the bar out as stamina expires.
Gif of fading in Action.

We multiply the fade-in and fade-out values to produce the final Alpha visibility.

Texture Logic - Middle

This section handles the visual texture of the ring:

  • • Multiply the MainTexture's RGBA output with the MainColor parameter.
  • • This combined result determines the final Base Color of the stamina ring.

Shape Logic - Bottom

This section shapes the ring using a radial threshold mask:

Left: Radial gradient input mask provided by the artist. Right: The radial texture used for the stamina ring’s shape.

Mask textures

  • • Sample the R channel of MaskTexture, subtract 1.0, and add StaminaPercentage.
  • • Clamp the result with Sign and Saturate to create a clean radial cutoff.
  • • Multiply this mask by the Alpha of the MainTexture to preserve soft edges.
  • • Then multiply again with the fade value from earlier to blend shape and timing.
  • • The result is a dynamic ring that cleanly fills and fades based on gameplay stamina.

Combined Result: These three sections work together to render a clean radial stamina bar, blending soft transitions, dynamic visibility, and clear mask-driven shaping.