Last node in color map is always black

[moreApi]

as seen for example here:

#757

[odinsbane]

@moreApi Your example is missing. I seem to be having an issue where textures turn black. If I select a new colormap it will briefly show color, then turn black again. Maybe it is related?

[smlpt]

@odinsbane the volume turning black is likely caused by this bug, for me it happens as soon as I hover over the color map editor.

[odinsbane]

Exactly. That is the issue I am having. I don't know if it is related to this issue.

[odinsbane]

This error is caused by Colormap#sample

val bufferPosition: Float = position.coerceIn(0.0f, 1.0f) * width

Indexes are 0 based so they should go from 0 to width - 1. This is 0 to width, but since the Colormap can have multiple bands it wraps back to the next band... which is black again.