Lost Coast Developer Commentary

Half-Life 2: Lost Coast was the first Valve game to feature Developer Commentary.

HDR Enabled
Below is the commentary ordered chronologically. Taken from the subtitles file for Lost Coast, they will only be shown if the player has HDR enabled.

"Welcome to the Lost Coast. In this tour, we'll be talking about a new graphics technology we've been developing, called High Dynamic Range, or HDR for short. We'll also be giving you some insight into the design and production challenges we faced during the construction of the Lost Coast. It appears that you either have HDR disabled, or your video hardware does not support HDR. You're still welcome to take a look around the level. First, a quick explanation of the commentary system. To listen to a commentary node, put your crosshair over the floating lambda symbol and press your use key. To stop a commentary node, put your crosshair over the rotating node and press the use key again. Some commentary nodes may take control of the game for the purpose of showing something to you. In these cases, simply pressing your use key again will stop the commentary."

- Gabe Newell

"With conventional rendering, seen here on the left, if something on the screen is 20% reflective, like the wet sand, then the maximum reflected brightness could only be 20% of the maximum brightness of your monitor. HDR's more accurate simulation of light ensures that the sun's reflection on this wet sand appears as it would in the real world, which could potentially use 100% of the maximum monitor brightness. HDR uses bloom to simulate light that is beyond 100% of a monitor's maximum brightness."

- Gary McTaggart

"The process of building characters in Half-Life 2 taught us many things. By the end, we believed we'd figured out a more effective process for designing and constructing characters. This fisherman is the first character we've built using that process. Design-wise, the fisherman was focused on showcasing HDR, and the way light falls on human skin. The highlights on his forehead and nose are good examples of specularity on human skin. You can see how the wrinkles on his cheeks, and around his eyes, are an example of how we can use normal maps to add depth. Production-wise, the fisherman was built using a similar process to the rocks you saw on the beach. We model the 3D character at a very high detail, then extract much of the physical information and store it in the textures."

- Randy Lundeen

"Water presents us with a lot of rendering challenges. In fact, we have to render the scene 3 times. Once for the refraction of what’s under the water, once for the reflection of everything above the water, and once from the player’s view. You can see the reflection & refraction scenes in the two small windows onscreen. In the refraction, we calculate, per-pixel, how much water you’re looking through to do a volumetric underwater fog, to simulate particulate matter. For our full HDR solution, we had to go through the entire engine and modify every bit of code that calculated light and color. For example, these water reflection & refraction renderings had to be improved to support the full range of contrast values."

- Gary McTaggart

"The area you're currently entering is called the cliffside arena. We were particularly happy with the vertical cliffside in Half-Life 1, and regretted that we didn't iterate further on that concept in Half-Life 2. Vertical space allows us to force the player to deal with threats from above and below. We find that players focus their view on the direction they're travelling, so by using a cliffside, and having the player ascend it, we ensure the player will look up and be prepared for enemies. If the player's path was to move past the bottom of the cliffside, it would be unlikely he would notice the soldiers rappelling down from above. Dying from unknown threats never feels fair, and certainly isn't fun."

- Robin Walker

"One of the features of our HDR solution is dynamic tonemapping. The easiest way to think about dynamic tonemapping is that it is a method of simulating the way the human eye reacts to light. In the real world, you’ve probably walked into a dark room and noticed your eye adjusting to the darkness, letting your see better after some time. Or you’ve walked out into a bright day, and been blinded by the sun, only to have your eye adjust and allow you to see normally. Your iris is adjusting itself in response to the amount of light hitting your eye. Dynamic tonemapping simulates this, by automatically adjusting the exposure of the scene to mimic the behavior of your iris. You can see this as the view moves from the dark tunnel to the bright sun, and back again. Here you can see the way we calculate the amount of light hitting the player’s eyes. We take a snapshot of the scene, and extract the brightness levels to get the average level of light. Additionally, we consider light at the center of the screen more important than that at the edges, to better simulate the geometry of the eye."

- Chris Green

"The courtyard in front of you is a space we call an Arena. Arenas are built to hold the player for a period of time, and usually contain combat or some other challenge. They often have multiple entry-points for enemies, along with a gate of some kind to prevent the player moving on, until the challenge has been completed. In this case, the arena is free of enemies until the player solves a puzzle, and triggers an alarm. This is a method that allows the player to explore the arena, and get a sense of its space before being forced to fight in it. It adds a sense of uneasiness to the player, who's expecting to be attacked now that they've reached the goal set for them at the start of the map. The break in action here is also a crucial part of the level's pacing. It allows the player to recover and explore the world a little, after being attacked on the way up the cliffside."

- Robin Walker

"The Source engine supports a wide variety of shaders. The refraction shader on the window here requires us to copy the scene to a texture, refract it, and then apply it the window surface. To fully support HDR, every shader in the engine needed to be updated, so this refraction shader was improved to the support the full range of contrast."

- Chris Green

"We wanted to transition from a bright, wide-open space into a tighter, closed one to showcase HDR’s dynamic tonemapping. We also like to focus on contrasting elements in our settings, like ancient human architecture and futuristic combine technology. A monastery fit these requirements perfectly. Monastery's are generally isolated, unlit, and built ages ago. They provide a great backdrop for the contrasting combine technology. When we build fictional settings, we try to ground them by basing them off a real-world location. We use this location as a design constraint that forces a logical consistency behind the art choices."

- Viktor Antonov

"Churches are great dramatic spaces. They’re often lit naturally, with extremes of darkness and brightness, which makes them a great showcase for HDR. Gothic churches are the sober, monochromatic spaces that you’ve seen in almost every horror movie or game. Byzantine churches, on the other hand, are very colourful and have a large variety of materials. We wanted that color & material variety to show off our HDR reflections."

- Viktor Antonov

"Our games are filled with things we call “gates”, which are essentially just challenges that the player must overcome to drive the experience forward. We used a puzzle here, since the player has been through combat and exploration recently. When we design challenges, we try to ensure that the player’s goal and the action required by the player are both fun. It’s not hard to create interesting goals for the player, like stopping this machine from shelling the nearby village. But the action required by the player to solve the challenge needs to be fun as well. So instead of something menial, such as hitting an off switch, the player gets to use physics to jam the gun’s mechanism and cause it to break."

- Robin Walker

"This marks the end of the Lost Coast tour. This has been an experiment on our part to see if our community would find it interesting to learn more about our development process. As always, we're interested your feedback. I can be reached at gaben@valvesoftware.com. If people like this, we’ll keep producing this kind of content for all of our games going forward. Thanks for listening!"

- Gabe Newell