Game Development Reference
In-Depth Information
Figure 4-9.
The TerraCottaBump normal map using default settings (left), reduced to 256 Max Size (middle), and adjusted for
more subtlety (right)
Earlier in the topic, it was mentioned that Unity shaders quite often commandeer a Texture's alpha
channel for other purposes. For textures that have no need of transparency, using the alpha channel
for a different purpose saves on resources. RGB uses 256 x 3 bytes. RGBA uses 4 x 256. By storing
some other grayscale information in a texture's alpha channel instead of another RGB texture, you
save 2 x 256 bytes plus the overhead of keeping track of the second texture. If an asset doesn't
come with the extra information, Unity can generate an alpha channel from the texture's grayscale.
For the terra cotta tile, it might be nice to have a glossiness map.
1.
Select the TerraCotta texture.
2.
Click Alpha From Grayscale, and click Apply.
The Preview now shows the color bar icon.
3.
Toggle the RBG icon to show the new alpha channel (Figure
4-10
).
Figure 4-10.
The TerraCotta texture's new alpha channel
