RPG engine development blog 1 – Inventory

I thought I’d start posting updates on my RPG engine’s development, as it’s starting to near to a point where a simple game could actually be built on it, and it’s nice to discuss it somewhere. While many features have already been implemented – dialog, maps and movement, NPCs, among others – there’s still a lot to do; dialog is still not as dynamic as I’d like, the scripting language isn’t super great so far, combat doesn’t exist, items barely exist, there’s no way to change area, etc. If you’re interested, a more detailed documentation is available at it’s README on GitHub, or on my projects page.


My first goal was to get some form of visualising the inventory. I’d made some GUI system for the dialog, so I leveraged that existing system and improved it where necessary. There wasn’t a way of having a GUI element render at a fixed position so I added a container that just offsets its children by a fixed amount, which is used to get the 30 item slots aligning nicely.

Initial stages of inventory development – moving items

After this, I hooked it up to the player’s inventory, and started displaying items from the inventory in the slots. After that, some trivial changes made it so that you can click an item to pick it up and then click elsewhere to drop it. This is visible in the image above.

Next, I added some inventory slots for nearby items on the ground, modified the map and hooked it up to allow the player to drop items where they are standing and pick up close-by items.

Some entity mis-rendering is visible in this video – you can see them clipping on top of the tree and over each-other. Currently, entity rendering is done after the entire map is rendered, rather than being interlaced, which leads to this issue. However, dropping items and collecting them works correctly as one may expect.

Next, I made some minor polish to hide the mouse cursor and render held items in the correct place when the player is moving an item.


I’ll be updating this post as I progress through the inventory system, hopefully completing it sometime in the coming weeks.

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