Using a special unlock template to ensure sync flags are up to date

gistfile1.txt

# TODO protect fields with inline procs that should get optimized out in release builds, but in debug builds can do asserts to make sure you unlocked it first

import opengl
import macros
import skyhash/xxhash
import sklog

type
    TextureParameterBrush* = object
        xhash*: uint64
        min_filter*, max_filter*: Glint
        wrap_s*, wrap_t*: Glint

proc `=changed`*(self: var TextureParameterBrush) =
    ## Updates the xhash of the parameter brush.
    var state: XXH64State

    template touch(x: untyped): untyped =
        discard state.update(cast[pointer](unsafeaddr self.x), self.x.sizeof)

    discard state.init 0
    touch(max_filter)
    touch(max_filter)
    touch(wrap_s)
    touch(wrap_t)
    self.xhash = state.final

template unlock*(tex: var TextureParameterBrush; mutator: untyped): untyped =
    block:
        defer: `=changed`(tex)
        mutator

var x: TextureParameterBrush

echo x.xhash
unlock x:
    x.min_filter = GlNearest
    x.max_filter = GlNearest
echo x.xhash