The Ring of Invisibility

[duncanc]

Stages:

• Never got the ring
  • !fIMPRESSED_ELF && !fCARRYING_RING && !fWEARING_RING && !fEGO_INVISIBLE && !fLOST_RING
• Given the ring by the elf
  • fIMPRESSED_ELF && fCARRYING_RING && !fWEARING_RING && !fEGO_INVISIBLE && !fLOST_RING
• Wearing the ring
  • fIMPRESSED_ELF && fCARRYING_RING && fWEARING_RING && !fEGO_INVISIBLE && !fLOST_RING
• Activated the ring by rubbing
  • fIMPRESSED_ELF && fCARRYING_RING && fWEARING_RING && fEGO_INVISIBLE && !fLOST_RING
  • vINVISIBLE_COUNTDOWN_LO = 250; vINVISIBLE_COUNTDOWN_HI = 10;
  • Decrementing until vINVISIBLE_COUNTDOWN_HI == 0 && vINVISIBLE_COUNTDOWN_LO == 1
• Lost the ring
  • fIMPRESSED_ELF && !fCARRYING_RING && !fWEARING_RING && !fEGO_INVISIBLE && fLOST_RING

Ring cannot be rubbed/will wear off immediately if:

• Accompanied by the goat
• In the gingerbread house
• Climbing the beanstalk
• In water
• Up the golden egg tree
• In mid-air
• Down the well (over or below the water)
• In the dragon's lair
• In the woodcutter's cottage
• Tiny from eating the mushroom
• Carried by the witch or the bird

[duncanc]

Hold the ring state in two variables, vUNDO_RING_LO and vUNDO_RING_HI. Store these when setting up an undo and restore them on completing it, unless it is certain that the ring cannot be worn at this point due to the rules above.

• If vUNDO_RING_HI == 100, we never had the ring.
• If vUNDO_RING_HI == 101, we are carrying but not wearing the ring.
• If vUNDO_RING_HI == 102, we are wearing the ring but it is not activated.
• If vUNDO_RING_HI == 103, we have lost the ring.
• Otherwise, we are invisible and vINVISIBLE_COUNTDOWN_HI/LO needs to be set to the corresponding values.