Improve particles and VFX, add blob shadow below player and enemies

[Calinou]

• Add projector light textures.
• Tweak the flying forklift's dynamic light and particles to be more noticeable.
• Add bullet impact particles with collision against level geometry (using a generated SDF).
• Don't use fixed FPS and disable interpolation to make particles smoother (trails aren't used, so fixed FPS isn't strictly needed).
• Add proximity fade to some particles to smooth out the transition with solid geometry.
• Fix some particles being shaded when they should be unshaded.
• Reduce crosshair size to be more subtle while aiming.

Preview

Videos:

• https://github.com/godotengine/tps-demo/assets/180032/c5f2b5ae-9a6c-40b1-8402-44596ecdafde
• https://github.com/godotengine/tps-demo/assets/180032/085616fd-23d4-45d9-bd2b-72fb034ccadb
• https://github.com/godotengine/tps-demo/assets/180032/e562d1bc-5a96-40e1-9212-675440bfd4d6
• https://github.com/godotengine/tps-demo/assets/180032/b069c855-4dfa-4b2c-a2b6-9d538edb1c97
• https://github.com/godotengine/tps-demo/assets/180032/032d40e2-9464-41e8-8f8b-90222a7a4105
• https://github.com/godotengine/tps-demo/assets/180032/2974e636-8038-44bd-9f0c-4bc9b13e6f50
• https://github.com/godotengine/tps-demo/assets/180032/0d7209f5-ddc3-4e0c-a714-8bc52ae90357
• https://github.com/godotengine/tps-demo/assets/180032/b374d921-a644-4563-af55-d35433f16914

[akien-mga]

Tested locally, it looks really cool! Thanks for working on these VFX, I felt they could use another pass for a long time.

There are two VFX which I think would still warrant more work, but that could be done in another PR;

• The robot enemy shot animation feels very underwhelming IMO, and there's also a position bug where the explosion happens on the robot instead of where it shoots.

https://github.com/godotengine/tps-demo/assets/4701338/95b9ad62-dd18-4e6c-b358-299d6d3d7e5d

Edit: GH doesn't like my encoding, but the video plays ok with mplayer or ffplay when downloaded. I've been struggling to get a proper recording with SimpleScreenRecorded today so fell back to old Kazam which might not be using state of the art formats.

• The "core" orb seen in https://github.com/godotengine/tps-demo/assets/180032/032d40e2-9464-41e8-8f8b-90222a7a4105 used to have much more pronounced "sun flare" effects that made it look more like a sun/fireball and not just a yellow glowy orb.

See the 3.x version of the TPS demo (at least as it was some time ago):

This was maybe lost during the conversion to Godot 4? The right amount of detail is maybe somewhere in between, but I do feel that having more activity that breaks from the pure spherical and almost flat shaded orb could be nice.

[QbieShay]

RE: Sun flare

I think I had some WIP for a fancier orb, but im not sure if i ended up pushing it upstream or not

RE: VFX

Feel free to improve them! Those were one of the first VFX I did when i started my VFX career, they can definitely use some improvement (especially those light shafts that I made in the past are a bit ... uuuuuhhh)