Valve Software, headquartered
in Bellevue, Washington, extended a gracious invitation
to attend their demonstration of HDR (High-Dynamic Range)
lightning, as it matriculates into the Source gaming engine.
The event was titled Lost Coast Day/HDR
Day and was held at the Valve Software office in Bellevue.
Invitations were extended to several major computer enthusiast
sites, along with Dr. Paul E. Debevec, who is the Executive
Producer for Graphics Research at the University of Southern
California, at the Institute for Creative Technologies.
Dr. Debevec wrote a paper entitled Recovering
High Dynamic Range Radiance Maps from Photographs which
was presented at SIGGRAPH 97,
and is generally now known as the “father”
of High-Dynamic Range. He continues to work quite closely
with Valve as they collaborate to produce even better, more
realistic lightning effects in computer gaming.
In the above photographs, the one on the left is the original
and the second a motion blurred Low Dynamic Range image.
In the next set of photos above, please
note the Motion-blurred HDR image on the left, then the
photograph with real motion blur located on the right.
A direct quotation from Dr. Debevec's paper
that was presented at SIGGRAPH 97 is noted
"Most image processing operations,
such as blurring, edge detection, color correction, and
image correspondence, expect pixel values to be proportional
to the scene radiance. Because of nonlinear image response,
especially at the point of saturation, these operations
can produce incorrect results for conventional images. In
computer graphics, one common image processing operation
is the application of synthetic motion blur to images. In
our results (Section 3), we will show that using true radiance
maps produces significantly more realistic motion blur effects
for high dynamic range scenes."
Via personal email correspondence with
Dr. Debevec, he stated the following below:
"My biggest contributions I think
are in lighting objects with HDR images, which Valve has
made inroads into getting into real time. The original SIGGRAPH
98 research for that was":
98 IBL Research
"This is the key technology behind
my animations "Rendering with Natural Light" at
SIGGRAPH 98 (which ATI made in real time in 2002 for their
Radon 9700 release) and "Fiat Klux" at SIGGRAPH
with Natural Light - SIGGRAPH 98
9700 Real-Time Demos
"This form of lighting CG objects
using HDR images at the incident illumination, officially
called Image-Based Lighting, is also known as "HDRI",
so it's sometimes confused with HDR images themselves."
One very interesting comment that Dr. Paul
Debevec made during the Valve presentation, was that the
SIGGRAPH 97 paper came out of darkroom work originally.
Quoting Dr. Debevec "The goal is to get real light
and reflectance and real people into games."
“The ‘dynamic range’
of a scene is the contrast ratio between its brightest and
darkest parts. A plate of evenly-lit mashed potatoes outside
on a cloudy day is low-dynamic range. The interior of an
ornate cathedral with light streaming in through its stained-glass
windows is high dynamic range. In fact, any scene in which
the light sources can be seen directly is high
dynamic range.” – Paul Debevec
(this quote from Paul was given in the 3rd slide from the
Power Point presentation which will be presented in full
later in this article).
Other tidbits gleaned about HDR from the
Valve presentation were as follows:
"A High-Dynamic Range image is
an image that has a greater contrast range than can be shown
on a standard display device, or that can be captured with
a standard camera with just a single exposure. (from slide
"High-Dynamic Range rendering
attempts to take an HDR image and produce a more realistic
representation on a limited-range computer monitor. (from
Valve software engineers Chris Green and
Gary McTaggart, along with Gabe Newell - Managing Director
and co-founder of Valve, Erik Johnson - Project Manager,
and Doug Lombardi - Director of Marketing, were all influential
in the presentation and follow up hands on gaming experience
given to several large web site attendees.
Valve Software is a Bellevue, Washington
video game developer, first made famous by their Half Life
product which was released in November 1998. Valve continues
to innovate by developing modifications to existing games,
spin offs and sequels such as Half-Life 2. Former long time
Microsoft employees, Gabe Newell and Mike Harrington founded
Valve in 1996, then obtained a license to the Quake gaming
engine. Half-Life was released on October 31st, 1998. Some
of the highlights include the Team Fortress Classic mod,
which was a port of the original Team Fortress (Quake) mod,
which was released in 1999. Valve continued to work on Half-Life,
and released more extensions to the game, and collaborated
with other developers in order to port the game to other
platforms. Valve continued development of the highly popular
Counter-Strike and Day of Defeat Half-Life mods.
Valve also created their own content management
system, known as Steam, in 2002. It was originally developed
to streamline the game patching process for online gaming.
It ended up becoming a replacement for Half-Life multiplayer
framework, and grew into a distribution system for entire
games, and updates. Some of Valve’s products include
Half-Life, Team Fortress Classic, Counter-Strike, Day of
Defeat, Deathmatch Classic, Steam, Half-Life 2 and their
famous Source engine. Their website is located here.
In April 2005, Valve announced an expansion
pack entitled Half-Life 2: Aftermath. According to Valve,
the planned release date for Aftermath will come sometime
in November 2005. Day of Defeat®: Source™, the
latest version of Valve's popular WWII online action game,
is available now for pre-load and pre-purchase. Day of Defeat:
Source leverages the Source engine's advanced features such
as high-dynamic range lighting, advanced graphics, and realistic
physics simulation. Valve is expected to release Lost Coast
as a freebie addition to those owning Half- Life 2 shortly
after the upcoming DoD: Source is distributed.
Valve Software used Lost Coast as an instrument
to demonstrate the effectiveness of High-Dynamic Range lighting
into video games. Valve employees continually stated during
and after the presentation, that HDR is seen as an incremental
technology. Valve used Lost Coast as a platform for ideas
initially brought up during the development of Half-Life
2 but not implemented at that time, for various reasons.
One is the head crab canister delivery system first planned
for use in HL2.
Lost Coast will be distributed for free
by Valve to HL2 owners, via Steam. A World War II themed,
Day of Defeat: Source has already been slated for release
on September 26th and has already entered pre-loading status
on Steam delivery servers.
Approximately two weeks or so after Valve
launches Day of Defeat: Source, the short techno demonstrative
Lost Coast addition to Half-Life 2 will be unveiled. Valve
is at this time planning to release Aftermath, most likely
in November and definitely before the end of this year.
Aftermath will be the first single player expansion for
Half-Life 2. Valve sees the Xbox version of HL2 as a way
to get more market share, and a method to let those who
have not yet experienced Half-Life 2 on a computer.
The Lost Coast addition will give you an
added 15 to 30 minutes of game play in an enhanced High-Dynamic
Range atmosphere. As a gamer, you will be quick to see the
differences ala the reflectance off water or sand, the wrinkles
in the fisherman's face and the specularity in his skin
tone, etc. Lost Coast is set up, where the game lets you
enter onto a beautiful beach, showing off the attributes
of HDR lightning effects to the maximum. As you rumble up
the shorefront, you will encounter the fisherman, who is
quite a polygonal masterpiece (over 6000 polygons went into
his making to showcase HDR). After you meet the fisherman,
he will tell you that the Combine have a large gun in a
nearby church. Since your character is the esteemed Gordon
Freeman, it is your job to tackle this assignment. You must
then traverse your way up narrow pathways leading up the
cliff side, overlooking Ravenholm. Eventually you'll arrive
at a beautiful church, with stained glass windows, demonstrating
the effectiveness and efficacy of the HDR and other design
elements, the whole idea behind HDR as demonstrated in Lost
Gabe Newell was asked by Chris Remo of
Shacknews, what set apart Lost Coast other than just the
visuals and gameplay. His response was that "There's
a reason the cathedral is important. You can't really know
why yet." Gabe refused to elaborate on
this point any further and left us all wondering about further
The following images were taken directly
from the slide show presentation by Valve at Lost Coast/HDR
Day. The one directly below was taken with a digital camera
at differint apertures, and shows with a narrow aperture
on the left, the sun is way overexposed, while the rest
of the image is under-exposed. As the photographer widens
the aperture to compensate, then you will end up with an
over saturated image, as shown in the far right side of
this thumb nailed image.
The two tone maps shown above are indicative
of exposure values being able to actually capture the details
included in a scene. You see what the effects of under and
over exposure are to game developers and end users.
Now it's time to share many screen shots
of the in-game beauty and detail of Valve's Lost Coast.
Please click on the thumb nailed images for a high resolution
view of the splendor!
Valve developed a commentary system for
Lost Coast. The first comment is by the crafty Gabe Newell
where he states "Hi. This is Gabe Newell and welcome
to The Lost Coast. In this tour, we're going to be talking
about a new graphics technology we've been developing called
High Dynamic Range, or HDR. We'll also be giving you some
insight into the design and production challenges we faced
during the construction of The Lost Coast."
To use the comment system just approach
the rotating icons in game, center your cross hairs on the
icon, and click your use key (the "e" key is the
one mapped in game for this). This bonus material is available
on an individual comment basis. Several explanations by
software engineers and Valve staff ensue, with some including
differing camera angles, split screens showing the differences
between LDR and HDR, etc. I will present a few of this snapshots
taken in game below in thumb nailed images. Please click
for the full high resolution view if you please.
Here are a few random shots of some in-game Lost Coast
Play I hope you'll enjoy.
Finally I wanted to show several views of the fisherman,
whose appearance I found spectacular. Please notice the
specularity of his skin tone, the wrinkles, how the reflection
of light off different parts of his face are apparent. After
seeing the original sketch of the fisherman and what the
final appearance was inside the game addition of Lost Coast,
color me very impressed by the efforts of Valve and their
staff to highlight HDR technology.
Some integral parts of the Lost Coast scene
play were the inclusion of the HDR Skybox technology, where
multiple exposures of the sky were painted in painstaking
detail. I believe there are 16 different HDR skyboxes included
in the Lost Coast demo alone. According to Randy Lundeen
- Level Designer and Graphic Designer who came to Valve
via Microsoft, like several other staff members, there were
3 main challenges to creation of the HDR skyboxes. These
were all hand authored using Adobe Photoshop and HDR
Shop. HDR Shop was developed by Dr.
Debevec after limitations of Adobe Photoshop ensued.
By painting multiple exposures of the sky,
Valve engineers were able to manipulate the imagery to allow
for real-time exposure adjustment.
Now let's briefly discuss HDR cube maps,
which are generated by the Source engine using the HDR skybox,
along with the HDR light sources and the HDR light maps.
If an object is reflecting the sun or another bright portion
of the scene, you will be able to see this in the full effect
of the brightness in the reflection. With HDR water reflection
or refraction, where the reflection of the sky is very bright,
you will see white hot spots along with blooming - if you
are under water, you will see a similar effect. Since we
just brought up HDR light maps, be aware that they are generated
from a radiosity process, that takes light bounces and global
illumination into account. In the cathedral pictures noted
previously above, you can note this effect on the wall of
the cathedral, where the sun appears to be blowing out of
HDR in game play does impact actual game
design as shown by Valve in their excellent presentation.
The main effects iin multiplayer games would be in moving
from light to dark areas or vice versa, i.e. coming in or
out of a tunnel.
Valve demonstrated that High-Dynamic Range
(HDR) lighting in real-time gaming applications with hardware
acceleration is definitely cutting edge technology. They
actually went through a tedious process of 4 different methods
of HDR implementation before finally settling on method
4. The slides presented by Valve on these differing implementations
will be presented below.
After thoroughly enjoying the Lost Coast
presentation from Valve, we proceeded into the gaming demonstration
room. The system specs which were used to demonstrate DoD:
Source consisted of an Athon 64 3800+ CPU, with 2GB of RAM
and utilizing a single GeForce 6800GT. I was able to play
the Lost Coast demo on my Acer TravelMate 8000 laptop which
carried 512 mebabytes of memory along with a Centrino 2.0
GHz chip, and an ATI Mobility Radeon 9700. At home I ran
Lost Coast on a Shuttle ST20G5 system configured as an HTPC
system, with a Hauppauge PVR-500MCE dual tuner card onboard.
This Shuttle system had a one gig pair of memory, and an
Athlon 64 San Diego 3700+ processor, and only one Chaintech
6600GT video card. Amazingly I was able to view the game
with no hitches or visual irregularities on it. I plan on
porting the game over to another Shuttle SN25P system I
am currently testing, which sports a PowerColor X850XT card,
so full eye candy will be available!
We have DIVX
avi's and ZIP files available, they are all optimised
and are 8 megabytes or less:
"HDR" - DIVX/AVI