|This article does not cite any sources. (December 2009)|
In computer graphics, wrapping is the process of limiting a position to an area. A good example of wrapping is wallpaper, a single pattern repeated indefinitely over a wall. Wrapping is used in 3D computer graphics to repeat a texture over a polygon, eliminating the need for large textures or multiple polygons.
To wrap a position x to an area of width w, calculate the value .
For computational purposes the wrapped value x' of x can be expressed as
where is the highest value in the range, and is the lowest value in the range.
Pseudocode for wrapping of a value to a range other than 0-1 is
function wrap(X, Min, Max: Real): Real; X := X - Int((X - Min) / (Max - Min)) * (Max - Min); if X < 0 then //This corrects the problem caused by using Int instead of Floor X := X + Max - Min; return X;
Pseudocode for wrapping of a value to a range of 0-1 is
function wrap(X: Real): Real; X := X - Int(X); if X < 0 then X := X + 1; return X;
Pseudocode for wrapping of a value to a range of 0-1 without branching is,
function wrap(X: Real): Real; return ((X mod 1.0) + 1.0) mod 1.0;