XCOM 2 gameplay systems презентация

UE3 and custom Firaxis
Not always appropriate, many side effects
Visual presentation and gameplay mechanics intertwined
Game elements hard-coded, strongly connected
XCOM 2
Game classes primarily custom Firaxis
Presentation separated from gameplay mechanics
Modular game elements

Context

Submit

History

Resolve

Network Layer

History

Validate

Submit

Observe

Control

Input

World & Actors

Control

Add

Game State Interface

the basis for UI
Unreal Engine Player Controller and Input classes are still used
Modular UI system allows screens to be constructed at run time.
Created for rapid prototyping, debug UI, and mod support.
Shipping UI generally does not use this system, but modular controls can be added / removed to shipping screens.
Many tactical UI elements recycled / reused from XCOM EU.

setup
The Game State System is the model
Game State System Classes
History
Record of all game state changes
Game State
Also referred to as “History Frames”
Game State Context
Holds meta information about what changed
Game State Object
Represents a game entity, full copy of the latest state of that entity

History

Game State

Context

StateObj

StateObj

StateObj

…

…

…

…

…

start state.
Start states typically contain a lot of state objects defining the initial state for most of the entities participating in the session.
Additional Game States / History Frames define new states for objects

History

Game State

Tactical
Game Start

BattleData
Map:
3x3 middle blocked

Unit
TileLoc:
X=0 Y=0

Game State

Std Move
Path:
X=0,Y=1
X=0,Y=2
X=1,Y=2
X=2,Y=2

Unit
TileLoc:
X=2 Y=2

Context: Information on how / what / why

State Object:
New state of a particular game entity

through map transitions.
No more intermediate systems passing data when changing game modes.

History

Game State

Strategy
Game Start

Game State

HQ Orders

Game State

Customize Soldier

Game State

Geoscape Interval

Game State

Launch
Battle

XCOM HQ

Time

Unit

XCOM HQ

Unit

Game State

Time

Archive

Alien HQ

XCOM HQ

Alien HQ

Unit

Time

XCOM HQ

Game State

Archive

XCOM HQ

Time

Unit

Alien HQ

Game State

Tactical
Game Start

BattleData

Unit

Alien Unit

XCOM HQ

Game State

XCOM Move

Game State

Alien
Move

Game State

Narrative Moment

Unit

Alien Unit

XCOM HQ

game state
Gameplay systems can read from the history directly.
Tracks information such as ability availability, active player
Subclasses provide game mode specific logic
Tactical rule set implements interrupt logic, turn phases
Multiplayer rule set includes turn timer, history serialization

system
Controls Unreal Actors to depict state changes
Strictly enforced data access
Visualizers are not permitted to affect game state.
The visualization manager must be able to operate from the History alone.
Relies on Game State Context to drive visualization.
The context contains the domain / state specific knowledge, so it builds the visualization when requested.

XComUnitPawn - XGItem & XComWeapon – XGPlayer
Purely visual
Core Visualization Manager Classes and Concepts
Visualization Block – Corresponds 1 : 1 with a game state being visualized
Visualization Track – Blocks have one track per state object in its associated game state
X2Action ( or Track Action ) – Tracks are composed of a sequence of actions. X2Actions make the visualizers run, shoot, step out of cover, etc. Many are recognizable as the XGActions used by XCOM EU, but with gameplay logic removed.

effects in EU were difficult to manage
Since mechanics were bound to visuals, mechanics that required prediction were difficult to impossible.
Better debugging tools
The game state history is navigable in-game via debug screen. Tracking down mechanical issues is often as simple as reviewing the history.
All saved games contain a full history. Saves are larger but can be used to analyze error reports.

a ‘finished’ history to replay game sessions.
Support for Replay brings other benefits
Robust mechanics support in Multiplayer – if it works in SP it will work in MP. Clients take turns building the history, and replaying remote updates to the history.
On-rails tutorial support. Replay can operate in a “follow the leader” mode where the replay UI looks identical to the normal UI, and is stepped forward by committing the next user action in the history.
Debugging: many bugs can be easily reproduced by loading a save provided by the QA team and replaying it. While running in replay mode, the user can halt replay and resume control at any point to reproduce issues that require input.