Sub-pixel

A portion of a pixel that can be addressed in certain circumstances. For example, the pixels on LCD displays have red, green, and blue sub-pixels that make up white. Because the pixels on LCD monitors are directly mapped to a physical location, it is possible access their sub-pixels which triples the horizontal screen resolution.

This appears to be how Cleartype works.

pretend that this is one pixel on an LCD: (note that it's hard to make square blocks of text in most fonts...)

RGB
RGB

now pretend that this is "v", rendered on a 3 by 3 grid (with a 1-pixel border around it):

RGBRGBRGBRGBRGB
RGBRGBRGBRGBRGB
RGB   RGB   RGB
RGB   RGB   RGB
RGB   RGB   RGB
RGB   RGB   RGB
RGBRGB   RGBRGB
RGBRGB   RGBRGB
RGBRGBRGBRGBRGB
RGBRGBRGBRGBRGB

(good job with the imagining!) Now with sub-pixel rendering, you actually draw on individual LCDs, rather than on pixels; here is a new and improved "v":

RGBRGBRGBRGBRGB
RGBRGBRGBRGBRGB
RGB   RGB   RGB
RGB   RGB   RGB
RGBR   G   BRGB
RGBR   G   BRGB
RGBRGB   RGBRGB
RGBRGB   RGBRGB
RGBRGBRGBRGBRGB
RGBRGBRGBRGBRGB

isn't that much better?

Now a side by side comparison (for your viewing pleasure) of a 5 by 3 pixel rendering of a "c". (again surrounded by a 1 pixel border)

RGBRGBRGBRGBRGBRGB   RGBRGBRGBRGBRGBRGB
RGBRGBRGBRGBRGBRGB   RGBRGBRGBRGBRGBRGB
RGBRGB      RGBRGB   RGBRG        GBRGB
RGBRGB      RGBRGB   RGBRG        GBRGB
RGB   RGBRGB   RGB   RGB    GBRG    RGB
RGB   RGBRGB   RGB   RGB    GBRG    RGB
RGB   RGBRGBRGBRGB   RGB   RGBRGBRGBRGB
RGB   RGBRGBRGBRGB   RGB   RGBRGBRGBRGB
RGB   RGBRGB   RGB   RGB    GBRG    RGB
RGB   RGBRGB   RGB   RGB    GBRG    RGB
RGBRGB      RGBRGB   RGBRG        GBRGB
RGBRGB      RGBRGB   RGBRG        GBRGB
RGBRGBRGBRGBRGBRGB   RGBRGBRGBRGBRGBRGB
RGBRGBRGBRGBRGBRGB   RGBRGBRGBRGBRGBRGB

(hint: the one on the right is better!)

thus concludes my demonstration of sub-pixel rendering.. hope you come back for the 5 o'clock show!

In pixel based video games, sub-pixel refers to a sprite having an x or y coordinate that is not reflected on the video display. For example, if the sprite is located at screen position x=128, 129 or 130, it will display in all cases as being at screen position x=128.

In a platform game like Super Mario Bros., sub-pixel can be very important, although they are unseen by the player. A jump might be possible to land if Mario jumps from x position 129, but not from x position 128. In these cases, whether a player can make the jump involves on intuition or more likely, luck. This is especially the case for executing glitches like wall jumping or clipping. In Tool Assisted Speedruns, where the sub-pixel value can be ascertained with a high level of certainty, jumps and glitches become easy to perform.