Tip 14 : When You Must Use Power Of Two!
Width and height of DXT textures must be power of two to be loaded and displayed by game engines. DXT compressed textures use block compression technique to reduce texture size. Since block compression algorithms operate on 4×4 texel blocks, you can’t use a dimension smaller than 4 for your DXT compressed texture. So 1024 * 4 is OK, but 1024 * 2 is not.
For more information about batch processing to change the file format of images to DXT format in Photoshop, please refer to this tutorial.
Tip 15 : Do Not Use Compressed Texture For UI Elements
Although it’s recommended to use compressed formats for most textures of your game, UI elements such as icons and texts are not a good candidate for compression and their artifacts are more noticeable if compressed.
Tip 16 : Bake To Textures
If you have trouble exporting effects and shaders from your 3D tool to your favorite game engine, try to bake those effects to textures in your 3D tool.
Tip 17 : One Larger Texture Is Better
One large texture is faster than multiple smaller ones. Modern GPUs like you to send data in large batches. Switching the textures means grinding everything to a halt which breaks the performance. So instead of submitting 4 similar shaders with different textures, try to combine those textures to one unit and send 1 shader to GPU in one large batch.
Tip 18 : Texture Anisotropy
Anisotropics texture filtering is a technique to increase texture quality when viewed at narrow angles. This technique is performed by the GPU at run-time and can be very costly. Due to that, only use this filtering for ground, ceiling, road, terrains, or any other object that may be viewed at shallow angles.
Tip 19 : Don’t Hesitate To Use NVIDIA Plugin
You can use NVIDIA texture tools for Adobe Photoshop to generate normal maps, mip maps, cube maps, and save textures as DXTC format. Simply download and install the plugin, then run Photopshop, and from the main menu of Photoshop, go to Filter | NVIDIA Tools… | NormalMapFilter. There are several documentations included in installation folder of setup file (In my case it’s C:\Program Files\NVIDIA Corporation\NVIDIA Photoshop Plug-ins 64 bit). These documents are very handy and explain all settings of NVIDIA texture plugin in detail.