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Oddworld%20:%20Stranger

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CoreObject = instance, made from tag, class factory, needs to be IO'd in save games. ... good game on time; clearly helped OW. Hopefully one tip here is useful ... – PowerPoint PPT presentation

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Title: Oddworld%20:%20Stranger

1
Oddworld Strangers Wrath
2
The good news
3
The bad news - youre not Valve or Bungie

Most of your team are weak links
Design is unclear and changes often
Have to make demos with little notice
Features get cut and added at all times
Content team and other coders dont follow the
rules

4
(No Transcript)
5
The Oddworld Method

Lead Programmers make the whole company more
productive
Use the code and engine to help other coders,
content developers
Improve your weak points, dont perfect your
strong points each company is unique
Rapid development and messy design iteration,
ease of changes, forgiving design tools

6
The Oddworld Method, cont.

robustness, flexibility, and rapid-response
the engine is at all times crash-free and can be
turned into a shippable demo on short notice
little tips to improve productivity are worth
millions
many of your coders are junior make it hard for
juniors to write broken code eg. Code that
seniors write should be self-correcting
self-enforcing

7
Never bring down other people

People make mistakes, you cant stop that
Make mistakes only affect that one system
Everything is in perforce roll back bad content,
bad builds
All code is reviewed
Compiler asserts table size checks
Exceptions

8
Background engine summary

All tools in Maya, all geometry triangle soup
Visibility through portals, clip frustum, scissor
Zones also define paging units and ticking
objects only current adjacent zones tick
Collision on triangle soup w/ KDtree and spatial
index
Lightmapper for static lighting cube maps for
characters material-based renderer with high
triangle throughput
Objects tick one by one and move themselves
simple zone-based manager
Paging in big blocks huge continuous levels with
persistent state

9
Exceptions

Not in final game
Not for normal errors, only for fatal errors
Default action is to propagate error better than
return values (malloc example)
Catch in individual object creation, tick
render
SEH is better than C EH, lets you write code in
the catch and provides call stack
Handler can detect attached debugger and int 3
Bad for cross-platform

10
Stack traces and error logs

Small binary stack traces on Xbox (64 bytes)
Parser on PC
Mailer to coders
VC double-click
Used for many things
Error messages for anything the artists can get
wrong. Log stack traces with every error.

11
Builder

Use free POP3 client just check mail to build
account
Run the subject line as a command
Batch file does syncincredibuildsubmit
Can easily do any task so also process lipsync,
make DVD, just use windows task scheduler

12
NetSlave

Simple distributed farm master machine controls
a set of slaves
Just a queue of commands, farmed out FIFO with
dependency analysis
Lets you use simple single-proc tools no need
for multi-proc bugs!
Slaves use p4 for data transfer

13
Memory Management

Systems use more or less memory at different
times.
Stack traced alloc tracker, parser for
hierarchies in tabview.
3 heaps contiguous (20 M, relocatable), small
block (5 M, fast), heap (used rarely at runtime).
STL and XMemAlloc directed into our allocators
Future separate heap for 64 meg debug data

14
STL

Saves dev time dev time is not just writing code
STL-port configurable
Vector is used heavily all other containers very
rarely used
Arrayltgt few C-style arrays, lots of vectors!

15
STL - vector

Release(), tighten(), tighten if excessive
Modified vector growth scheme doubles on PC,
limit at 4k on Xbox
Vecsorted like a map, but tight in memory
sometimes faster
Vector_s, vector_t, vector_a note that the base
vector class itself is 12 bytes

16
Inst/Def paradigm

Many insts created from one shared def
CoreObject instance, made from tag, class
factory, needs to be IOd in save games.
Resource def, const, made from binary data
blocks, const, shared, kept in memory across
level loads, etc.
Many other things use inst/def

17
IOZ (the Z is for cool)

Templated type-traits based IO system.
Client code is very easy just call IOZ on all
members all logic is compile-time
Type traits and template specialization know if a
type is binary or not, also if vectors are
vectors of binary, etc.
Pointer IO CoreObject or Resource?
Resources written as Token references
CoreObject data must be written once, but other
pointers just write references (use the
RefCounted table index)

18
Smart Pointers

Every type should clean itself up on destruction,
so pointers should too.
Other types of GC would be okay GC reduces
errors, GC is required for exceptions. SP is the
simplest form of GC.
Weak Pointers a reference, not a hack 4 bytes
4 for table entry. Table also provides index
for IO. (2 byte table index, 2 byte UID)

19
Smart Pointers, cont.

Cant have loops use Weak or Naked for back
pointers must have a tree-structure of
ownership.
Pass naked pointers avoids exposing interface
and avoids temporaries cant do with boost style
SP, need base class RefCounted need to be a
little careful with this.
Stack-trace ref tracking for ref leaks catches
loops and other bugs.

20
Tweaker and Prefs

Text is nice for p4 diffs and searches with
simple perl tools making spreadsheets of all
healths, dependency finding, etc.
Cvar no per instance overhead, handles MI. In
the future, generic template Reflection visitor.
GameControl system for spatial overrides and
inheritance
In the future more pref inheritance with
rule-based inheritance, eg. Super Wolvark
Wolvark w/ health2

21
Resource Bundler

Just load the level and track resource queries.
Bundle resources for NPCs, Zones, cines, etc.
Bundle optimization minimize bundle count,
constrain to 64 meg limit, minimize total bundle
size

22
ArtWatcher

Watch dirs with ReadDirectoryChangesW, copies
content to Xbox and notifies game ArtWatched
resources override bundled content
Does p4 adds (we add .cpp and .h files too),
helps artists a lot
Right click menu for common tools
One error on restart, ArtWatched info is lost

23
Other stuff

Skeleton LOD
Cube Map Lighting
Practical PSM
Decorator Renderer
AI System
Animation control
but technology is easy!

24
Conclusion

Code responds well to bad use enforces rules,
never crashes, flexible, easily changed.
Finish a good game on time clearly helped OW
Hopefully one tip here is useful at your company
No C bashing please

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