Date:
Wednesday, September 05, 2007
Author:
Mark Warner
Editor:
Brent Justice
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BioShock DX10 Performance and Image Quality

BioShock, one of the most anticipated titles of recent history, hit the scene with a resounding BANG, bringing with it foul cries of RootKit! We look past the paranoia to find out what our shiny new DX10 video cards will do for us in BioShock.

Introducion

Previously, we examined DirectX 10 performance and image quality with two different titles, with wildly different results. When we looked at Lost Planet: Extreme Condition, we found that the DirectX 10 codepath offered nothing revolutionary (or indeed interesting), and the game was better played in DirectX 9 mode. Lost Planet inflicted a disproportionate performance penalty for the luxury of running in DirectX 10, and offered no meaningful incentive. Then, when Call of Juarez came under our magnifying glass, we could not have been more pleased. The DirectX 10 version offered vastly improved visuals and solid performance.

We've examined two full retail DirectX 10 games and we are still no nearer answering what our readers want to know, ”In a general sense, what does DirectX 10 do for me that DirectX 9 does not?” Unfortunately, there is no definite answer yet. Lost Planet offered us nothing, and Call of Juarez seemingly offered us a much more immersive gaming experience. Today, we're going to add BioShock to our testing suite, and are again asking, “What does BioShock’s DirectX 10 version offer me over DirectX 9, and how do current DX10 video cards perform in the DX10 version of the game?

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BioShock

BioShock, according to 2kgames:

BioShock is the "genetically enhanced" first person shooter that lets you do things never before possible in the genre: turn everything into a weapon, biologically mod your body with plasmids, hack devices and systems, upgrade your weapons and craft new ammo variants, and experiment with different battle techniques in an incredible and unique underwater city.

It is a new twist on an old formula. BioShock comes from the same minds that brought us the Sci-Fi shooter masterpiece: System Shock 2. As such, many of the story elements (such as RPG-style characterization) and gameplay mechanics (such as "Hacking") may seem familiar to a few veteran readers. Virtually every functional machine can be hacked to work for the player, and those that can't be hacked can be destroyed. Weapons can be upgraded, skills can be upgraded, and even the player's own body can be augmented by the use of Plasmids and DNA tonics.

The whole hodge-podge of FPS and RPG takes place in the failing days of a former utopian society called "Rapture", created by one man to serve himself, and for others to serve themselves. The entire affair is at the bottom of the Atlantic Ocean, and the water seems to desperately want its space back. Add to that formula the moral dilemma of whether or not to save or harvest the "Gatherers," and you have BioShock in all of its complexity and nuance.

DirectX 10

To add to the brilliant environment and truly make it feel realistic BioShock is a DirectX 10 enabled game under Windows Vista. It is powered by the Unreal Engine 3, built by Epic Games. Within the game, there is but one cryptic option related to DX10 called "DirectX 10 Detail Surfaces". That seems to imply that there is some special handling of object surfaces (i.e. textures and shaders) using DirectX 10 features.

According to NVIDIA, BioShock makes use of at least three DirectX 10 features. First, and most apparent in-game, is that it reads back depth buffer values on particle effects, which allows for processing the intersecting edges of the particles producing “soft” particles. It also uses DX10's DCF + texel offsets for shadow map filtering, which is what makes DirectX 10 shadows look better. Third, it supports packed 32-bit floating point render targets, using the R11G11B10 backbuffer format. That is 11 bits each for red and green, and 10 bits for blue. Many, if not most, DX9 games use R8G8B8X8, which allows only 8 bits per channel, with an often unused alpha channel. Simply put, R11G11B10 allows for finer color control.

This game takes place entirely underwater, and as such there is a massive use of water effects. Some more subtle DX10 improvements include improved ripples as a result of characters moving through the water. There is a great deal of pixel shader usage to create detailed and wet looking surfaces. There is also HDR and extreme lighting used to emphasize certain visual aspects. This game overall is very dark but thankfully not “Doom3 flashlight” dark. The environment is spectacular and we will find out if DX10 really does give us an edge over DX9 or not in this game.

Testing

We will be testing BioShock on five different video cards, representing the Enthusiast and Performance classes from both ATI and NVIDIA. All of our performance tests will be on an apples-to-apples foundation, but we will provide our highest playable settings. Finally, we will provide image quality comparisons to outline what DX10 and DX9 bring to the table in BioShock.