darkness and brightness," providing an ideal showcase for the HDR lighting effects. Valve also thought a monastery would help provide a starker contrast between old human architecture and futuristic Combine technology inside it. The cliffside that leads to the monastery had a gameplay-oriented purpose, and was meant to emulate a similar cliffside combat scene in the original Half-Life (1998). The cliffside also forces the player to be observant of threats from above and below, breaking from normal horizontal combat. The monastery's courtyard was designed as an area where the player recovers from the cliffside combat, while also presenting a contained combat arena later in the level in which the player must hold their ground while they are attacked from multiple directions. High-dynamic-range rendering The goal of Lost Coast was to demonstrate the new high-dynamic-range rendering implemented into the Source game engine. Valve first attempted to implement high-dynamic-range rendering in Source in late 2003. The first method stored textures in RGBA color space, allowing for multisample anti-aliasing and pixel shaders to be used, but this prevented alpha mapping and fog effects from working correctly, as well as making textures appear sharp and jagged. The second method involved saving two versions of a texture: one with regular data, and the other with overbrightening data. However, this technique did not allow for multisample anti-aliasing and consumed twice as much video card memory, making it infeasible. The third method, shown at the E3 convention in 2005, used floating-point data to define the RGB color space, allowing for reasonably efficient storage of the high-dynamic-range data. However, this method also did not allow for multisample anti-aliasing, and was only compatible with Nvidia video cards, leaving ATI cards unable to run high dynamic range. The fourth and final method compromised between the second and third methods, using overbrightening textures sparingly and allowing ATI cards to render HDR in a different way to the Nvidia ones while nearly producing the same result. The final version of Valve's high-dynamic-range technology adds a significant number of lighting effects to the engine, aimed at making the game appear more realistic. Bloom shading was introduced, blurring bright edges in the game world and emulating a camera's overexposure to light. This is combined with exposure control to tailor the effect to represent the human eye. For example, as the player exits a dark area into a light area, the new area is initially