SCANNER
The DistortionBall Shader is a stylized transparent sphere effect designed to resemble energy shields, scanning bubbles, or distortion fields. Built entirely with Unity HDRP Shader Graph, it features screen-space refraction-like distortion, dual scrolling noise, Fresnel-based edge highlighting, and depth-aware intersection fading. This breakdown dissects the shader into five functional modules, explaining the logic, key nodes, and underlying rendering principles behind each visual element.
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PART 1 - Distortion IOR Offset
This module simulates a refraction-like effect (Index of Refraction, IOR) by distorting the scene behind the object using screen-space UV offsets. This creates a parallax-like visual that mimics light bending through a transparent medium.
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Screen Position - Provides screen-space UVs (usually for sampling Scene Color).
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Split & Multiply - The RGB values are scaled by the user-defined IOR_Scale to adjust distortion strength.
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Combine & Add Noise - The offset UVs are combined and augmented with procedural noise to add dynamic warping.
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Scene Color - The final distorted UV is used to sample the screen's rendered color.
PART 2 - Noise Scrolling
This module introduces movement into the distortion by applying time-based scrolling to noise patterns. These serve as dynamic UV offsets, adding a sense of energy flow.
Dual Scroll UV
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Time + ScrollSpeedA/B - Two float inputs create separate time offsets.
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Vector2 Combination - Offsets are packed into a vector for directional UV shift.
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Tiling and Offset - Used to scroll a noise texture dynamically.
Noise Multiplication
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Gradient Noise + Sample Texture2D - Two noise sources are layered to increase visual complexity.
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Multiply with DistortionStrength - Amplifies the impact of noise-driven displacement.
PART 3 - Fresnel Rim Glow
The Fresnel effect highlights the edges of a 3D object based on the angle between the surface normal and the camera view vector. It enhances the visual silhouette and mimics realistic reflection behavior.
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Fresnel Effect Node - Operates in World Space for view-dependent edge detection.
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Power - Controlled via FresnelPower to fine-tune the glow intensity.
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Color Blend - Blends FresnelColor with CenterColor using Lerp for smooth transitions.
PART 4 - Intersection Fading
To avoid hard edges when the sphere intersects with other geometry, depth comparison is used to create a soft fade along the edge, simulating realistic interaction with the world.
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Scene Depth vs. Screen Depth - Computes distance from the camera to the background and the object.
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Subtract & Smoothstep - Creates a soft mask based on how close the object is to intersecting.
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One Minus - Inverts the fade mask for correct edge highlighting.
Application Ideas
Sci-fi Energy Shields
Scanning Spheres or Drones
Portal Effects
Time Warps or Distortion Zones
