flipU()

Flips the geometry’s texture u-coordinates.

In order for texture() to work, the geometry needs a way to map the points on its surface to the pixels in a rectangular image that's used as a texture. The geometry's vertex at coordinates (x, y, z) maps to the texture image's pixel at coordinates (u, v).

The myGeometry.uvs array stores the (u, v) coordinates for each vertex in the order it was added to the geometry. Calling myGeometry.flipU() flips a geometry's u-coordinates so that the texture appears mirrored horizontally.

For example, a plane's four vertices are added clockwise starting from the top-left corner. Here's how calling myGeometry.flipU() would change a plane's texture coordinates:

// Print the original texture coordinates.
// Output: [0, 0, 1, 0, 0, 1, 1, 1]
console.log(myGeometry.uvs);

// Flip the u-coordinates.
myGeometry.flipU();

// Print the flipped texture coordinates.
// Output: [1, 0, 0, 0, 1, 1, 0, 1]
console.log(myGeometry.uvs);

// Notice the swaps:
// Top vertices: [0, 0, 1, 0] --> [1, 0, 0, 0]
// Bottom vertices: [0, 1, 1, 1] --> [1, 1, 0, 1]