games-pc tiger woods pga tour 2003 ユーザーズマニュアル

THE EDGE OF YOUR COURSE

One of the illusions of 3D graphics is the sense of perspec-

tive. A well-designed 3D graphics engine conveys the sense of
being able to see to the natural horizon. However, the horizon is part of the
illusion.

When a 3D engine displays graphics on the screen, it must compute

positional, rotational and scaling information for every object and the rela-
tionships of each object to the other objects on-screen. These objects must
then be displayed as a series of overlapping layers, with the nearest objects
on the top layer. However, objects in the layers further from the camera
require the same computations and calculations to display. Yet, if these
objects are partially or completely obscured by the closer objects, then
there is not much added value in finishing these calculations. Additionally, if
the object is tiny on-screen, the calculations to precisely position, size and
rotate the object have little value to the overall appearance of the frame.

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In the case of realtime 3D graphics engines for first-person point of view
games, it is especially important to minimize the computations required
to display a single frame. The mathematics involved are fascinating,
complicated and quite beyond the scope of this document.

In the Course Architect, the elements that need to be displayed are the

terrain, the textures and the objects on the course. Yet, it would take too
much computing power to display courses that extend into infinity. And con-
sider the amount of time to develop to infinity. Imagine that you're creating
a course on a hillside overlooking a beautiful valley. If you were required to
create terrain, textures and objects to the limits of sight, you would have to
create an entire valley. Yet no golfer would ever see or play on your beauti-
ful valley. Infinite Valley would demand much processing power to display
with very little benefit.

Consequently, to improve performance in the Course Architect and in the

game, you can put limits to the perimeter of your course. You can define the
edge of your course, called the course perimeter, so that both the Course
Architect and the game can speed the display of non-essential material to
the horizon. At the course perimeter, the Course Architect allows you to hang
photo-realistic images of the horizon, called panoramas, to convey the sense
of perspective. How to define and tweak the course perimeter and then
choose an appropriate panorama is the subject of this chapter.

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Also covered in this chapter are skies. The sky displayed in the Course
Architect is established in the Sky Picker tool. In the game, users can
select their own weather conditions to create custom environments.