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Chapter 4 Perspective, Scene Design, and Basic Animation
Alpha channels can also allow for a masking color. A
masking color
is a
single shade of a color that can be set to be transparent. If you have ever seen a
weather report on TV, you have likely seen them using a masking color. Using
a green or blue screen, called a chroma screen, will allow a background of the
weather map to digitally replace the blank screen. In image creation, mask
colors are typically chosen so they will not interfere with natural colors. Using a
masking color such as white would be a very bad choice. If white was made to
be transparent, then the whites in a person’s eyes and other white items would
be transparent.
Vector Images
Another popular type of image is a vector image.
Vector images
are
images composed of lines, curves, and fills. Vector images do not store
the color value and location of each pixel. Rather, the image is displayed
based on the mathematical definition of each element in the image. In
other words, in a raster image a line is composed of dots, while in a vector
image the line is defined by a mathematical equation. For a vector image to
be displayed, the software must rasterize the image before it is sent to the
display device.
A vector image can be a very small file size because the image is drawn
by the computer using a mathematical formula. Since the formula draws the
image, the image can be resized infinitely smaller or larger without loss of
clarity. This is one of the biggest advantages of a vector image.
However, raster images offer an advantage over vector images because a
vector image requires the CPU to work hard to draw the image. In the world of
handheld devices with small CPUs and low memory, a vector image may have
the benefit of small file size, but may take up a large amount of CPU ability.
Bitmaps do not take up a large amount of CPU ability, but have higher file size.
The designer will need to understand the limits and capabilities of each device
on which the image will be rendered to correctly match the file size and CPU
usage to prevent lag and crashing the device.
Ethical Gamer
It is important to be respectful in your use of
computer equipment. It is unethical to use the
computer, without permission, for personal
means such as playing games, shopping, or other
activities that are outside of your assignments.
It is also unethical to access confidential
information, download copyrighted material, or
harass others. Many organizations monitor users
to make certain that the computer activity is
ethical and legal.