Alpha translucency is unusable in MT anyway and is discouraged.

well, water uses it.

Water uses an alpha parameter alpha = 160, instead of use texture alpha = true for using a texture's alpha, maybe this is why it works in inventory?
So if you use a custom water node using alpha = should work?

@paramat... it appears to ignore nodedef alpha parameter, both on the map and in the inventory, using texture alpha instead (despite use_texture_alpha=false in the definition).
And that’s not a something custom but default MTG water.

Alpha translucency is unusable in MT

That’s equally true both for node alpha and texture alpha, there is no difference for rendering.

I hope it gets fixed eventually, that blinking and glass behind glass is pretty major graphic problem.

If the alpha is in range [128, 255], the inventory cube is visible but dark.

So why do default water nodes look fine in inventory?
We don't use 'inventorycube' anymore btw.

For items and wield items texture alpha is ignored, as it is described described there.

If you would like to experiment, change these two lines in the source (and disable shaders):
for inventory items
for wield items

@juhdanad thank you.

So why do default water nodes look fine in inventory?

@paramat it doesn’t, it’s darker than it should be.

Anyway, don’t bother with it, I’m going to bisect it myself.

They're only slightly darker, and maybe because they are being blended with dark grey behind.

alpha = 255 makes water source in the world opaque, and with 255 you can see the top of the inventory image is similar brightness to the top of the node in the world.

However very low alpha values do not make water clear in the world, there seems to be a minimum alpha similar to the texture alpha, perhaps 'alpha' nodedef and texture alpha are combined?

However alpha = 0 does not make water completely clear in the world, there seems to be a minimum alpha similar to the texture alpha,

That's a bug, fixing PR is #5494

Still happens, not with MTG water but with nodes (liquid at least) which use_texture_alpha. Seems that inventory mesh is drawn with EMT_TRANSPARENT_ALPHA_CHANNEL_REF instead of EMT_TRANSPARENT_ALPHA_CHANNEL.

@Ezhh may have experience of this?

Confirmed bug. This is default:water_source in the inventory adjusted to have alpha = 100

Not sure of cause.

Confirmed bug as well in 5.2.0-dev @ 80af58c with this minimal node definition and a fully opaque texture:

          minetest.register_node("testnodes:alpha_120, {
                  description = "Alpha Test Node",
                  drawtype = "liquid",
                  paramtype = "light",
                  tiles = {
                          "testnodes_node.png",
                  },
                  alpha = 100,
                  groups = { dig_immediate = 3 },
          })

@nerzhul: How many confirmations are required to re-open this bug? ;-)

Closing was a mistake due to misunderstanding of my comment #5461 (comment)

Bump. This is still an issue (and I wouldn't consider it "low priority"..)

Plus this is also annoying for servers since players can't see stuff that is less alpha in inv.