Week 4 - What I'm Aiming For

No, these stupid post titles aren't going to end any time soon. Sorry, not sorry.

Another decently productive week down; I managed to get aim functionality in pretty smoothly, all things considered. The blend spaces I set up last week to clean up my animation tree made plugging this stuff in pretty easy. For anyone who's curious, here's what the inside of a blend space looks like: 

Direction along the bottom represents which way the player is facing, and Aim represents where their gun is pointed vertically. If the player pressed up or down, I set the value to 1/-1, and if they press diagonally up or down I set it to 0.5/-0.5 instead. The zig-zag lines... really aren't important since this animation is sprite based. Since I already put placeholder nodes in, once I got the input reading functionality working under the hood I just had to swap out the animations at each node as needed.  Of course, that involved setting up more animations, but I find that I've been getting better at the Godot animation workflow so it didn't end up being as time consuming as I feared. Nintendo really didn't skip on detail for this games animations though. Did you know that there are separate turning animations depending on whether you're currently aiming up or down?

As part of the aiming functionality, I also hooked in the 'diagonal lock' input. For those of you that may not be as familiar with Metroid, it is as simple as the name sounds; you hold a button and Samus aims diagonally up or down, even if you're not currently pressing the D-pad. Super Metroid was set up to have two such buttons; one for aiming upward and one for aiming downward. There was a bit of an oddity in the design however, and the game did not allow you to re-assign these inputs to non-shoulder buttons. This might not have been a problem for most players, but if you're like me and you can't stand having the Sprint button assigned to a face button (it makes trying to run, jump, and shoot at the same time basically impossible), that meant you effectively lost the ability to aim in one of the directions while standing still.

That being said, the GBA Metroid games had a solution for this, since the handheld had fewer buttons to work with.  Holding the button locked you in a diagonal aim mode, and pressing up or down transitioned your aim in that direction. Pressing down while already aiming diagonally down would make Samus crouch while maintaining the same aim direction, and similar transition would happen if you pressed up while aiming diagonally up when crouching. I always preferred the feel of this setup over the one that they had in Super Metroid, and so I opted to use that implementation instead in this case.

​Anyway, with the directional aiming taken care of, I was able to finish implementing some more movement tech that is dependent on it. Specifically, the ability to break out of a spin jump by aiming vertically, and the ability to enter and exit morphball while in the air:

Aiming downward while in the air is pretty interesting, as it's treated differently than aiming in any other direction. If the player releases the Down button, they don't actually stop aiming downward. Only pressing a different direction will break you out of it, so it's sorta like an airborne equivalent to the crouch state... though I didn't give it it's own state here, just some fancy logic to prevent Samus from returning to neutral from a downward aim and a bit more to prevent her from entering morphball when she isn't already pointing down.

I know for a fact that there's plenty more nuance to the work I did this week that I'm largely glazing over, but the end result is simple; you can point your gun at things now. The next task on my todo list is the obvious continuation from this one; make it so that you can actually shoot the gun. Projectiles in Super Metroid are not at all complicated, so I don't expect any issues there, but I imagine making sure the projectile spawns in the right spot and goes the right direction might be a little more tricky since there aren't animation bones I can use and the positioning of the cannon isn't consistent between different animation states. I think I have a few ideas on how to handle it, but we'll see how it goes.

​See you next time.