Particle Shader

Light-Reactive Volumetric Particle Effect

Design:

Solution:
- Shader developed for custom particle behavior.
- For use with simple particle system approach, the effect is based on a material shader for billboarded quads. Transparency is reactive to per-pixel lighting values. Uses forward rendering and supports multiple light sources, including their individual light colors, fall offs, and shadow-casters.
Context:
- Project required volumetric lighting for atmospheric effects.
- Unity’s Built-In Render Pipeline is not optimized for ray-marched based fog volumes.
- The project required a light-weight solution (minimal impact on FPS).
- The art pipeline specifically resulted in minimal overdraw from scene assets, so transparent particle based approach was selected. This approach afforded clear benchmarking and optimization since the impact of overdraw could be specifically attributed to density of this effect.

Features:

Supports Unity’s Particle System fading/transparency conditions
Works in “day” and “night” conditions
Effects normalized around a directional light intensity of 1 for ease of use
Uses procedural world space noise to simulate wind with full directional and morph rate controls
Allows for different mask textures to control particle “volume”/”density” representation
Implement soft-particle falloff to minimize quad/billboard-based artifacts
Through testing, works with as few as 5 layers between camera and light sources
Particle-based system allows for specific spatial localization, and simple logical control to disable CPU load for distant and out of frame Particle Systems
The shader captures illuminance for Post Processing effects like Bloom
Artist-friendly naming convention for ease of use

Notes:

Light and particle intensity turned up for demonstration purposes
Supports light cookies for softer falloff for spot lights, but omitted for clarity

Terrain Shader

Artifact-Free Tiling Terrain Shader

Design:

Solution:
- Shader developed for Unity’s terrain system and editing tools, supporting splat mapping and built-in PBR texture support
- Uses shader-based proceduralized texture variance to hide texture tiling artifacts
- Supports Unity “Standard” shading, and additional requested feature - Parallax Occlusion Map
Context:
- Project required solution to problem with minimal impact to existing tech stack and terrain pipeline, and zero impact to existing level designs
- Specifically, Level Designers were using Unity’s built-in Terrain components, and built-in terrain editing tools (using height and splat maps)
- Project’s performance budget required minimal use of large (2k+) textures, so increasing texture size was not viable

Features:

Drop-in replacement for Unity’s Standard Terrain Shader
No impact to, or loss of functionality from, Unity’s terrain editor workflow
Uses procedural random rotation and blending to hide texture seams
Blending supports Albedo, Normal, and Mask maps
Additionally supports POM using height map input, and per layer-POM strength
Easily modifiable to support custom lighting, snow accumulation effects, tint-based variance layering, etc.
Simple tuning features to support a wide range of high-frequency noise variance in albedo and normal textures
Artist-friendly naming convention for ease of use

Notes:

POM disabled to heighten visibility of “seams” (visual tiling artifacts")

Material Shaders

Custom Lighting Shader with Inverted Hull Outlines

Design:

Solution:
- Custom Forward Lighting shader using soft-transition stepped toon lighting
- Support PRB texture workflow, including Albedo, Normal, and AO, with architecture for future support of smoothness, metal, clipping, and detail layers
- Inverted hull outline feature for aesthetic reinforcement, and selective application for design language (visual hierarchy)
Context:
- Developed for personal project that required toon lighting
- “Homemade” solution developed for unified lighting behavior across variants, such as:
  - Foliage - Noise-based wind animation for foliage
  - Simple - Outline free variant for environmental assets
  - Emissive - HDR variant for emissive sources
  - Terrain - Unity Terrain system support for splat maps
  - Water - Water variant with vertex offset animation for waves, computed normals for accurate lighting, and localized wave height suppression for ports
  - UV2 Support Sprite Sheet Flipbook - UV2 support with option for independent lighting behavior, permits the use of quantized sprite sheet for hand drawn facial expressions

Features:

Per-material Global Illumination base color (shadow color) step
Albedo texture base color step
Lit color step with control over inclusion/exclusion of light color contribution (broadcast Anime style vs digital illustration style)
Tunable ramps for transitions for soft edges
Supports fog
Skinned Mesh (Rigged Character) features like clipping mask - prevents body from visibly clipping through clothing under extreme deformation
“Normal Power” calculation to suppress/amplify normal map impact on lighting
Allows for simple style transfer for “photoreal” style assets
Artist-friendly naming convention for ease of use

Notes:

References below are all using variants of the same toon lighting shader (or other custom made shaders like wet glass, particle rain splash flipbook.

Effects Shader

Mesh Animations, Trail Effects, Screen Space Post-Processing Stack Effects

Demo Reel 1:

VFX System

All effects managed under single Effects Manager
Effects Manager operates with dynamic object pool, reusing existing objects, and dynamically creating new ones when overflow requires
Dynamic object pool is genericized so any game object / prefab can be managed, and any in-scope parameter can be observed for management
Effects can be controlled via static class accessor
- Effects.Fire(string name, Vector3 pos, Quaternion rot;
Generic Effect Controller base class allows for the control of multiple various effects and rendering component control and scheduling (TrailRenderer, ParticleSystem, MeshRenderers, etc.), max lifetime, transform scaling, spatialized SFX firing, etc.
Generic Effect Controller utilizes SubClass Sandbox Pattern for easy variant creation
Generic Effect Controller has surfaced features for configuration, tuning, and customization in editor

Effect 1 - Bullet Trail

Task-based lifecycle management
Primary animation VIA CPU trail vertex (points) animation
Secondary animation VIA GPU (shader) vertex deformation animation
Screen space blue-noise dither fading for consistent lighting in overlapped regions

Effect 2 - Mesh Particle Explosion with Collisions

When crab enemies are killed, tentacle mesh particles are emitted upon death
Tentacles are animated using vertex deformation shader
Animation operates in world-space to prevent deformation scaling as particles scale
Particle system utilizes collisions to prevent clipping through terrain and other physics colliders

Effect 3 - Paper Particles

Uses Particle System to launch sheets of paper
Use of velocity, drag, noise, rotation, scaling to replicate high-surface-area-low-mass behavior

Effect 4 - Anime-Style Spherical Explosion Effect

Optimized UV sphere used to add topological density along vertex animation areas (fewer longitudinal divisions, greater latitudinal divisions)
Scaled (squashed) noise-based world space vertex deformation animation
Noise algorithm output used as color ramp mask
Task-based lifecycle management

Light-weight Animation Workflow

Hybrid Shader-based Vertex Animation and CPU-based Static Mesh Animation

Light-Weight Animation Workflow

Use of various optimization techniques reduces both CPU and GPU impact
Entity concepts are analyzed to look for alternative animation approaches to preclude need for armatures (rigs) and blendshapes, which can be CPU intensive

Static Mesh Animation

Using mesh object hierarchy in place of armature permits familiar FK animation workflow
Reused meshes (crab legs) can be efficiently rendered using GPU instancing because it is a static mesh (i.e. no mesh vertex changes)
Further optimization possible by reusing a single set of shared leg mesh assets (i.e. every leg is using the same mesh object so 1, NOT 8, meshes are packaged for the GPU)
Simple pose interpolation for locomotion cycles can be controlled by a single shared manager to further minimize CPU impact
Usage in examples:
- Crab legs - 4 pose cyclic rotation interpolation
- Crab teeth - 2 pose cyclic rotation interpolation
- Crab and Jellyfish tentacles - local space rotation
- Jellyfish eye - randomized local rotation

Vertex Deformation Animation

For repeating simple movements, vertex offset animation in-shader can massively minimize the cost versus armature-based or blendshape based animation
Using vertex painting, or texture based masking, animation scale and timing offset can be customized
For the jellyfish:
- Vertex color R-channel is used to control magnitude - the top of the jellyfish body and base of smaller tentacles have an R-channel value of 0 to dampen animation effect
- Vertex color G-channel is used to offset animation timing - the smaller tentacles have a higher G-channel value than body to apply offset to time so they move off-cycle from body slightly
For the tentacles:
- Sinusoidal movement applied in local space to create wiggly movement
- Randomized rotations on a per-instance basis can prevent appearance of synchronized animation across instances