The mipmap magFilter to be used when creating textures.
You can specify this as a string in the game config, i.e.:
renderer: { mipmapFilter: 'NEAREST_MIPMAP_LINEAR' }
The 6 options for WebGL1 are, in order from least to most computationally expensive:
NEAREST (for pixel art) LINEAR (the default) NEAREST_MIPMAP_NEAREST LINEAR_MIPMAP_NEAREST NEAREST_MIPMAP_LINEAR LINEAR_MIPMAP_LINEAR
Mipmaps only work with textures that are fully power-of-two in size.
For more details see https://webglfundamentals.org/webgl/lessons/webgl-3d-textures.html