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Gl.IndexMask (gb.opengl)
`Static Sub IndexMask ( Mask As Integer )`

Control the writing of individual bits in the color index buffers.

### Parameters

mask

Specifies a bit mask to enable and disable the writing of individual bits in the color index buffers. Initially, the mask is all 1's.

### Description

Gl.IndexMask controls the writing of individual bits in the color index buffers. The least significant $\mathit{n}$ bits of mask, where $\mathit{n}$ is the number of bits in a color index buffer, specify a mask. Where a 1 (one) appears in the mask, it's possible to write to the corresponding bit in the color index buffer (or buffers). Where a 0 (zero) appears, the corresponding bit is write-protected.

This mask is used only in color index mode, and it affects only the buffers currently selected for writing (see Gl.DrawBuffer). Initially, all bits are enabled for writing.

### Errors

Gl.INVALID_OPERATION is generated if Gl.IndexMask is executed between the execution of Gl.Begin and the corresponding execution of Gl.End.

### Associated Gets

Gl.Get with argument Gl.INDEX_WRITEMASK

### See also

Gl.ColorMask, Gl.DepthMask, Gl.DrawBuffer, Gl.Index, Gl.IndexPointer, Gl.StencilMask