func Pow2(x uint32) uint32 {
	x--
	x |= x >> 1
	x |= x >> 2
	x |= x >> 4
	x |= x >> 8
	x |= x >> 16
	return x + 1
}
Pow2 returns the first power-of-two value >= to n.
This can be used to create suitable texture dimensions.
package glh
import (
	"fmt"
	"image"
	"image/color"
)