This is the TGLTexture magnification filter. Magnification filter means how a texture is displayed when the texture is magnified eg when you walk up close to a wall how is the texture displayed.

TGLMagFilter is defined as the enumerated type:

TGLMagFilter = (maNearest, maLinear);

maNearest 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.

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

For a more definitive description of minification and magnification filters check out:

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

Unit: GLUtils