Thread by @tesselode

A subtle tip for people integrating #egui with a game engine:

egui provides wants_pointer_input(), which tells you if the mouse is over a UI element. If so, the rest of the game should not receive mouse input. Same with wants_keyboard_input().

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#rustlang #gamedev

egui doesn't know if it wants input until *after* you call end_frame(). So you should run your UI code at the beginning of the game loop, before the rest of your game receives events or does updates.

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#rustlang #gamedev

In my case, I'm integrating egui with Tetra, whose game loop is:
- Poll and dispatch events
- Call update (maybe, depends on the timestep)
- Call draw

Here's how I integrate egui with those phases of the game loop:

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#rustlang #gamedev

Event callbacks:
- Send the event to egui
- Queue it up for later

Update:
- Run the UI code and save the meshes
- Send the queued events that the UI didn't want to the gameplay code

Draw:
- Draw gameplay
- Draw the meshes

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#rustlang #gamedev