Laying the Groundwork - Learn SpriteBuilder for iOS Game Development - page 48

with 8 bits for each RGB color channel and another 8 bits for the alpha channel (transpar-
ency).
Figure 2-25 . Sprite sheet publish format settings
Tip The RGBA4444 and RGB565 formats reduce color bit depth to 16-bit,
which can cause “color-bleeding”—specifically, in images with gradients. For
these formats, you may want to enable the Dither check box. The RGB565 is
suitable only for images without any transparency—for instance, opaque back-
ground images—as it trades additional color vibrancy for the alpha channel.
The PVRTC variants are a “last-resort” measure since they use a lossy compres-
sion, much like JPG, but they will further reduce memory usage and improve
rendering performance. You should only consider using PVRTC for fast-mov-
ing, short-lived, or small images—where the reduced quality isn't noticeable.
For instance, a spritesheet containing nothing but variations of bullets could be
an ideal PVRTC candidate. If in doubt, experiment. The original images will be
left untouched, you can always revert the spritesheet export format without any
loss.
Now that you have turned the Global folder into a Sprite Sheet and set its export format,
you should drag and drop the player.png provided in the topic's downloadable archive
from Finder onto the Global sprite sheet folder. Be sure to drag the image itself, not the
folder containing the images. The other images will be used at a later time.
If you want to use your own player image, you should create an image that's 256 x 256
pixels in size and its contents circular in shape, and name it player.png . The player is cir-
cular because later in the topic it will become a deformable soft-body physics object, and
a circular shaped image is easiest to draw onto a deformable body.
Tip Dragging and dropping files from Finder onto SpriteBuilder's File View is
the only way to add external resource files to SpriteBuilder.
Creating the Player Prefab