Generating Mip Maps

Mip maps are a sequence of optimized images made from one image. Each image is lower in resolution than the previous image by a power of two. Mip maps reduce the time and processing power it takes to render an image in a game. Lower resolution mip maps are used when the viewing distance is great enough that the loss of detail is not noticeable. Higher resolution mip maps are used when an object is close to the camera and needs to be displayed in detail.

When you enable mip maps in Lumberyard, Resource Compiler automatically generates six mip maps for that image. The largest mip map is the original size of your image, and each progressive mip map is smaller by a power of two.

Example

If your original image is 1024x1024, then you will have mip maps that are 1024x1024, 512x512, 256x256, 128x128, 64x64, and 32x32.

Example

If your original image is 4096x4096, then you will have mip maps that are 4096x4096, 2048x2048, 1024x1024, 512x512, 256x256, and 128x128.

Note

For most of the existing presets, mip maps are enabled by default. If you create your own presets, you must enable mip maps.

If mip maps are not enabled, then on the MIP Control tab, under Mip maps, none (0) appears.

To enable mip maps for an image processing preset

1. In a text editor, open the rc.ini file, located in the lumberyard_version\dev\Bin64vc141\rc directory.

   For more information, see Creating Image Processing Presets.

2. Add mipmaps=1 to the definition.

   Example

   ...
   [AwesomeImage]
   pixelformat=BC1
   pixelformat:es3=ETC2
   pixelformat:ios=PVRTC2
   ;pixelformat:es3=ASTC_4x4
   ;pixelformat:ios=ASTC_6x6
   rgbweights=ciexyz
   powof2=1
   mipmaps=1
   colorspace=sRGB,auto
   ;discardalpha=1
   filemasks=*_awesome*
   ...

   To disable mip maps, specify mipmaps=0.

Adjusting Alpha Test on Mip Maps

You can adjust the Alpha Test value for each mip map in the MIP Control tab of the Resource Compiler image tool.

To adjust Alpha Test for each mip map

1. For each mip map, adjust the sliders or enter a number in the box.

2. Select Maintain alphatest coverage to maintain shape and opacity from a distance when working with certain types of objects, such as leaves on a tree. If you don't select this option, the tree leaves may lose their silhouette in the lower resolution mip maps.