As described earlier, the (u, v) texture coordinates that you assign to your vertices are what determines how the texture fits on your geometry. Often, you will use texture coordinates that always fall within the range [0, 1], which is the complete range of the pixels of your texture image. However, it is also legal to use texture coordinates that go outside this range; you can have negative values, for instance, or numbers higher than 1.

So if the texture image is only defined over the range [0, 1], what does the texture look like outside this range? You can specify this with the texture wrap mode.

texture.setWrapU(wrapMode)
texture.setWrapV(wrapMode)

The wrapMode parameter is specified separately for the u and v directions (there is also a setWrapW() for 3-D textures, but that's an advanced topic). The wrapMode may be any of the following values:

The default wrap mode is WMRepeat.

Consider the following simple texture image:

We will apply this texture in the center of a large polygon whose texture coordinates range considerably farther than [0, 1] in both directions.

WMRepeat

texture.setWrapU(Texture.WMRepeat)
texture.setWrapV(Texture.WMRepeat)

WMRepeat mode is often used to tile a relatively small texture over a large surface.

WMClamp

texture.setWrapU(Texture.WMClamp)
texture.setWrapV(Texture.WMClamp)

WMClamp mode is rarely used on large polygons because, frankly, it looks terrible when the pixels stretch out to infinity like this; but this mode is usually the right choice when the texture exactly fills its polygon (see One caution about a common wrap error, below).

WMBorderColor

texture.setWrapU(Texture.WMBorderColor)
texture.setWrapV(Texture.WMBorderColor)
texture.setBorderColor(VBase4(0.4, 0.5, 1, 1))

The above blue color was chosen for illustration purposes; you can use any color you like for the border color. Normally, you would use the background color of the texture as the border color, like this:

texture.setWrapU(Texture.WMBorderColor)
texture.setWrapV(Texture.WMBorderColor)
texture.setBorderColor(VBase4(1, 1, 1, 1))

Some very old graphics drivers don't support WMBorderColor. In this case, Panda3D will fall back to WMClamp, which will look similar as long as there is a sufficient margin of background color around the edge of your texture (unlike our sample texture, which goes all the way out the edge).

WMMirror

texture.setWrapU(Texture.WMMirror)
texture.setWrapV(Texture.WMMirror)

Many older graphics drivers do not support WMMirror. In this case, Panda3D will fall back to WMRepeat.

WMMirrorOnce

texture.setWrapU(Texture.WMMirrorOnce)
texture.setWrapV(Texture.WMMirrorOnce)
texture.setBorderColor(VBase4(0.4, 0.5, 1, 1))

Few graphics drivers support WMMirrorOnce. In this case, Panda3D will fall back to WMBorderColor.

Setting different wrap modes

It is possible to set different wrap modes in the u and v directions:

texture.setWrapU(Texture.WMRepeat)
texture.setWrapV(Texture.WMClamp)

One caution about a common wrap mode error

When you apply a texture that is intended to exactly fill a polygon--that is, the texture coordinates range from 0 to 1, but no further--you should usually set its wrap mode to clamp. This is because if you let it keep the default value of repeat, the color may bleed in from the opposite edge, producing a thin line along the edge of your polygon, like this:

This is a particularly common error with a texture that is painted as an alpha cutout, where there is an image with a fully transparent background: you will often see an thin, barely-visible edge floating along the top (for instance) of the polygon. This edge is actually the bottom edge of the texture bleeding onto the top, because the designer specified WMRepeat instead of the correct mode, WMClamp.