The TGLMinFilter is the filter used by TGLTexture when a texture in minified (TGLTexture minfilter property). For example, if you were to have a sprite with a tree texture, how will the tree be displayed when it is moved into the distance.

TGLMinFilter = (miNearest, miLinear, miNearestMipmapNearest, miLinearMipmapNearest, miNearestMipmapLinear, miLinearMipmapLinear);

miNearest means that the color of the nearest pixel (point sampling) is used to display the texture which has the least computational costs and the lowest quality.

miLinear is the interpolation among neighboring pixels, which needs more computing power, but looks better.

The other minification filters use mipmapping. When using mipmapping the system calculates scaled down textures of the original textures to remove aliasing effects in the distance. These extra textures will cost some more texture memory but can improve the visual quality of the scene a lot.

miNearestMipmapNearest has switching to smaller textures when you get more in the distance. This is the quickest filter that uses mipmaps but the result is poor and this setting is seldom used.

miLinearMipmapNearest adds the linear interpolition of a 2x2 grid on top of the mipmap switching. This gives a good result and is a good and relative quick filter.

miNearestMipmapLinear has linear interpolation of the colors removed, but now the points are not taken from one mipmap (sized down texture), but are combination of two mipmaps.

miLinearMipmapLinear is the most expensive but visually the best filter. It interpolates between mipmaps and takes the averaged color in a 2x2 area.

Screenshots and some explanations taken from Joran Jessurun site with permission. His site is at

http://www.ds.arch.tue.nl/General/Staff/joran/wup/Default.menu?menu=6

Unit: GLUtils