The document provides an overview of the Effects Conduit, which is a framework for collaboration on visual effects in video games. It allows developers of different roles to focus on their specialties by separating the work of triggering effect events from responding to those events. The Conduit includes GUI tools, a data builder, and runtime components to play effect specifications in response to events without requiring extensive programming.

1. Effects Conduit
Technical Presentation
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2. First things
This is review for some

 I’ll try to make sure there’s fresh material
 I’m shy about talking about my ideas
 (false)
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3. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

Quiz

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4. What is the Effects Conduit?
What is it not?

 Not a visual/particle effects system
 Not a sound effects system
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5. What is the Conduit?
A framework for collaboration

A collection of components

 Suite of GUI tools for all developers
 Data builder
 Runtime
Motivation

 In the past, programmers have spent a lot of time
“hooking­up” & tweaking effects – not a programming
task
 Developers (read: I) have struggled with this problem
time and time again.
 It’s solvable!
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6. What is the Effects Conduit?
Anybody can get effects into the game & iterate

Separate work

 People who cause effect events
 People to respond to effect events
Let people focus on what they’re good at

 Reduce busy­work
 Empower content creators
Rapid prototyping

 Apply generic effects quickly
 Specialize effects as they become available
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7. What is the Effects Conduit?
Published in Game
Design used in 

Developer Magazine,
 Insomniac Titles
March, 2005
Ratchet &
Clank
Future:
Tools of
Destruction
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8. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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9. Terminology (revised)
Effect Event

Something that happened during game­play

Response

What should happen in response to the Event

 Refer to Effect Specifications (▼)
Spec

How/where to play an effect

 Which effect to play
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10. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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11. Model
Code

 Animation
 Game­play (scripts)
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12. Model
Most events are Some happen over
 
instantaneous time
 Triggered, e.g.  Triggered &
UnTriggered, e.g.
BOUNCED

BURNING
DAMAGED 

HOVERING
DIED 

GRINDING
EXPLODED 

ROLLING
LANDED 

SMOKING
THROWN 

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13. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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14. Components
GUI Tools

 “Conduit Tool”
> fxconduit

Configure

responses…
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15. Components
GUI Tools

 “Conduit Tool”
… and Specs

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16. Components
GUI Tools

 “The Editor”
[Un]Trigger events from key­frames of animation

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17. Components
Builder

 > conduitbuilder {level}
 Reads dependencies to determine what
Conduit data (responses & specs) is required
 Invokes SubsystemHandlers to build
subsystem data referenced by Conduit data
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18. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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19. API
API is minimalistic

Gameplay API in Moby/ControllerBaseUpdate

 void TriggerEffectEvent(type)
 Results TriggerEffectEvent(event&)
EffectsConduit

 void HandleEvent(event&, results&)
 Subsystem& GetSubsystem(subsystem)
For playing explicit specs

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20. API
EffectsSubsystem

public: PlayExplicitSpec(spec, source*, …)

 protected: virtual bool ShouldSelect(event&)
 Pure Virtual:
PlaySpec(spec, response*, source*, …)

SetEffectPosition(handle, location*, facing*)

StopEffect(handle, bool kill)

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21. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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22. Implementation
­ Block Diagram
Note: Some details are out­of­date
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23. Implementation ­ Data Structures
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24. Implementation ­ Selection
Selection Criteria

 Mandatory (every Event and every Response specifies these)
Update Class

Event Type

 Optional (to further specialize Responses)
Art Class Score = 1 << 0xF

Other (Update Class) Score = 1 << 0xE

Tag Score = 1 << 0xD

Gore Score = 1 << 0xC

Material Score = 1 << 0x9/A/B

Value Score = 1 * range

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25. Implementation ­ Selection
Effect Event triggered (from code, gp, anim, etc.)

Each Subsystem (visual, sound, dialogue, etc.)

EffectsSubsystem::HandleEvent(event&, results&)
 Each class from source to IGG::GameObjectUpdate
Consider Responses to Event Type

Compare Event with Response for each criterion:

 Unspecified: ignore criteria
 Don’t match: reject response
 Match: add criteria score to response
 Until a Response matches
 All highest scoring Responses (for the class) are selected
 Each selected response
Call effects system (visual, sound, etc.) to play Specs

The same Event can match at different Classes in

different Subsystems!
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26. Implementation ­ Responses
Structurally similar to Effect Event

 Where Event may identify only a material id,
Response can identify class, subclass, or id.
 Where Event may identify a value, Response
identifies a range of values.
Contains a list of Specs to be played if

Response is selected
 Play on Other
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27. Implementation – Specs
Specs configure effects

Subsystem Specs extend base Spec

 Base Spec includes
AttachType

UpdateMode

Refractory period

 Derived Spec contains subsystem­specific
configuration data, for example:
Volume (for Sound)

FxPackage (for Visual)

Priority (for Dialogue)

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28. Implementation ­ TrackedEffects
TrackedEffect::Collection is a member of

EffectEventResults, returned by
TriggerEffectEvent
Operate on the Collection as a whole…

EffectEventResults::Untrigger(bool kill)

 TrackedEffect::Collection::SetPosition(…)
… Or modify individual effects

 Iterate over TrackedEffects
 Optionally filter by Subsystem
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29. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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30. Future
Optimizations

 Never untrigger events… only results
Remains only in animation

 Multi­level jump table for responses
 Hint selected responses in results
 Cache responses or specs in results
In practice, performance impact is small

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31. Future
Features

 Contexts
 Better searching in tool
 Tool & Editor integrated into Luna
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32. Outline
What is the Effects API
 
Conduit? Implementation

Terminology Future
 
Model References
 
Components

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33. References & More Info
Game Developer Magazine

 “Moment of Impact”, March 2005.
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34. Quiz – Question 1
Matt found that rifle bullet hits weren’t playing material­specific

effects.
Here were the responses to Projectile_Rifle_Bullet_HIT in the

VisualEffectsSubsystem:
When a rifle bullet hit the ground, Matt expected the Conduit to play a

spec under the Projectile_Rifle_Bullet_HIT {materials={Ground}}
response, but it didn’t.
Why not? How should you fix it? (The answer is on the next page.)

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35. Quiz – A1
The Conduit was selecting the

Projectile_Rifle_Bullet_HIT
{tag=NOT_PLAYER} response
instead of the
Projectile_Rifle_Bullet_HIT
{materials={Ground}} response.
Both responses matched the
event since both of them correctly
describe the event that happened.
(The bullet did hit a “not player”,
and the bullet also hit a material
ground.) But the
tag=NOT_PLAYER response got
a higher score, and therefore beat
the materials={Ground} response.
So how should he fix it?

Well, the answer is to delete the

tag=NOT_PLAYER response.
That way, the Conduit will select
the next­best match… the
materials={Ground} response!
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36. Quiz – Question 2
Okay, so now the responses to Projectile_Rifle_Bullet_HIT in the

VisualEffectsSubsystem are:
When a bullet hits the ground, the Conduit plays the effects that Matt wants.

But when a bullet hits metal, there are no visual effects at all!

How can Matt get everything he wants… ground effects on ground, and

generic effects on metal?
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37. Quiz – Answer 2
The reason Matt was getting no visual effects when the rifle bullet hit

metal, was because none of the responses matched that event.
What Matt needs is a response that will always match when a rifle
bullet hits anything. Remember that the Conduit always selects the
most specific response(s) to any event. So even if there’s a
response that always matches, others may play instead because
they’re more specific.
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