I am creating a real-time ray-traced game. And the last few days I spent on creating a world-editor for it.
The world-editor is in-game, so I can simply drag and drop elements from a palette into the world, and immediately use the newly created objects.
It's quite intuitive and lets you play "lego" or "doll-house" quite easily. My 7yo daughter loves helping me out with gamedev, so I will ask her to test drive the world builder for me, and see what she will come up with .
My game is written in C++, but using a mostly C-style coding. It is pretty mean and lean, but does require AVX2 at the moment. At some point I will have to port that to AVX to support more PCs out there. Currently, it is running in Linux on top of SDL2 and OpenGL 3.2, with my own custom engine.
Here is a video of me demonstrating the editor.