The plan is to add a structure which represents a single input event which contains the event type (key down and key up to start with) and some data (which key), add a List to the window to store the input events, add a function to dequeue the next input event from a specific window and return it, and the window manager will need some method of getting keyboard events into the queue.
Reviewing how the Linux Doom source code processes input, it seems to fetch XWindow events in a similar manner, converts them into Doom input events, then calls a Doom function to push them into a queue. I'll reinstate a version of this code, but wired to get the event using my new function and modified to convert from my event structure into the Doom event.
One note here is that the XWindows GetEvent() function blocks if there are no events to serve, and the Doom code calls a separate function to determine if there are events ready so that the game doesn't stop every frame waiting for input. My function will return NULL if there are no events, so I'll need to adjust the code in Doom to account for this.
Having modified Doom to read and process the input events, I need to get some events into the queue. Whilst I do have a PS/2 keyboard handler in the kernel, it's wired up to output ASCII values from key down events only, where as we need key up and key down events for all the keys, even non-ASCII ones. In order to test the event pipeline and the event handling code in Doom, I've put some code into the OpenWindow() function to push some key presses into the event queue of the Doom window, specifically 'Escape', 'Enter', 'Enter', 'Enter' which should bring up the menu, select 'New Game', select the episode, then select the difficulty to start the game.
All this in place and it works a treat. Doom loads, then goes into the menu, and starts the game, leaving the character standing at the beginning of level 1. \ o /
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