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 below:

"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":

SIGGRAPH 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 99)."

Rendering with Natural Light - SIGGRAPH 98
Radeon® 9700 Real-Time Demos
Fiat Lux

"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 #5)."

"High-Dynamic Range rendering attempts to take an HDR image and produce a more realistic representation on a limited-range computer monitor. (from slide #6)."

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 Coast.

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 direction.

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 the wall.

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 - ZIP

"SHOT" - DIVX/AVI - ZIP

"COMMENTARY" - DIVX/AVI - ZIP

"WALKING AROUND" - DIVX/AVI - ZIP

 

Next: Lost Coast: Inside Valve (2)