Twin-stick shooter controls

26 Sep 2018

Currently UniBlaster (the main engine of RetroWar) supports four different games / character types. They are similar in many ways, but the controls vary slightly.

• Droids use the right stick to aim, and automatically shoot a stream of low powered bullets (A)
• Tanks use the right stick to aim, but require the button to pressed to shoot a single high powered projectile (B)
• Ships cannot aim, fire straight forward when the button is pressed (C)
• BombBots have no gun so cannot aim, drop bombs when button is pressed (C)

I've been thinking how to create a more general abstraction of these differences.

Instead of one weapon, each character would have three weapon slots:

• A fires when right stick is moved, unless button is depressed
• B fires when right stick is moved and button is depressed
• C fires when right stick is neutral and button is depressed

This would allow characters to carry multiple weapons and use all three without any switching and only needing one fire button.

Possible uses:

• The current shooting-type A/B characters could gain a close combat C weapon.
• Player has a choice between firing a stream of low power bullets, or one high power bullet that will take time to reload. (Also can make reload not begin until player has finished aiming - see CrossCode for example of this.)
• Player could be given a choice between firing low power bullets, or pressing the button and firing high power bullets but reducing his speed, perhaps to zero. (Need to add speed reduction option to weapons)
• Player could be given a choice between shooting and dropping bombs, depending on whether he moves right stick.
• An A type weapon that does no damage, but merely assists in getting the aim right before the B type weapon is fired.
• A B type weapon that doesn't fire when the button is pressed, but when it is released. Thus holding the button down does nothing, so fire rate entirely depends on how quickly the button is mashed. The amount of time the button is held before release could determine how charged up the weapon is. Why not fully charge every shot? Because charging reduces your movement speed.

Finally, I've been thinking about how RetroWar could be played on actual 8-bit joysticks. Currently 8-way d-pad movement is supported in all games as a virtual stick, (although it puts you at a disadvantage in most of them that aren't grid based.)

But then how to aim when there is no second stick for aiming? You could just fire in whatever direction the sprite is facing when the button is pressed. But that would fire the C type weapon, which is likely to be non-directional bomb anyway, and leave no way to fire the A directional gun. Games like Paradroid handled this by requiring you to move a bit before pressing fire. So the virtual input would create a second stick pointing in the same direction as the real left stick when you press the button with no input from any right stick. Many games also had a locking mechanic, so once you started shooting you held down the button to lock the firing direction while you could move in a different direction. Not sure how that could work in my scheme.