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Feature: Real-Time Cameras - Navigation and Occlusion
by Staff [PC, Console/PC]
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July 1, 2009
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Gamasutra is proud to present an excerpt from the book Real-Time Cameras by Mark Haigh-Hutchinson, a veteran Retro Studios staffer who was diagnosed with pancreatic cancer in 2008 and passed away in 2009.
The book, published posthumously with help from his colleagues and friends, is available now. For more information on the book's creation, please read this blog post, and today, our Gamasutra feature presents an section on the camera as AI object.
In many ways, the problems presented by camera navigation have parallels within the domain of artificial intelligence (AI). As suggested earlier [in the book], the camera may be thought of as an AI character, at the very least in terms of the determination of its position and orientation within the game world.
The camera may be able to move more freely than many types of AI characters, however, since it is typically floating rather than being constrained to moving on surfaces or under the influence of a physical simulation. This freedom of movement is one of the benefits of a virtual camera system when compared to real-world cameras.
Haigh-Hutchinson also shares dynamic navigation techniques like ray casting:
One of the simplest and most common navigation methods is that of the ray cast, a mathematical projection of a straight line through the virtual environment. By using trigonometry it may be determined if the line would intersect with either the collision geometry corresponding to the environment or that of an object within it. As might be expected, this can be computationally intensive especially given the complexity of many environments.
An important goal when implementing camera systems is to limit the amount of such testing whenever possible. Amortization of ray casting is entirely possible and can be quite effective in reducing the processor requirements at a cost of limiting the amount of information available to use for navigation.
Fortunately, navigation does not require a per-frame updating of such information as its decisions are normally longer lasting and may take more time to evaluate than collision or other immediate concerns. Similarly, reducing the set of data to be compared against (e.g., using spatial partitioning or material filtering) is also recommended.
You can now read the full book excerpt in today's Gamasutra feature (no registration required, please feel free to link to this feature from other websites).
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