Ok, just tried it in the real game.
First, on positive side, when switched to Bullet, the physics doesn't blow up anymore! That's a win!
On the negative side
1) Even though concave mesh collision shape is created, I can see it with Debug/Visible Collision Shapes check box. But for some reason collisions don't happen. Bodies fly right through.
2) Even though joints are created, they don't work for now. Constructions just fall apart when pushed.
Ok, new update: godot.windows.editor.x86_64_b49f801f3.zip.
Fixes:
The return of bullet physics in Godot 4 is one of the biggest achievements along with the introduction of Vulcan. Is it possible to make a module for Godot? This will please many developers. Not everyone will want to install a separate build or compile it, a module will allow you to distribute your work throughout the community. In any case, I want to thank you. This gave hope to our studio to stay on Godot in the future, as we decided to switch to another engine due to physics.
Engardium Is it possible to make a module for Godot? This will please many developers. Not everyone will want to install a separate build or compile it, a module will allow you to distribute your work throughout the community. In any case, I want to thank you.
Great idea, thank you! I know they've changed binary modules design process a lot but didn't look into it yet. I'll check what it takes to make a module out of Bullet physics server...
Engardium Bad news.
I've been trying to convert it to GDextenstion. I've checked out godot_cpp.git 4.0.2-stable tag which corresponds to 4.0.2-stable godot current version.
The obstacle I've encountered is G6DOFJointAxisFlag enum in Godot : : PhysicsServer3D and godot_cpp : : PhysicsServer3D do not correspond to each other. G6DOF_JOINT_FLAG_MAX is not defined in godot_cpp as well as a few other enums.
So, I guess having Bullet physics as a GDextension binary plugin is delayed... For now only the built-in version is available.
I've created an issue: https://github.com/godotengine/godot-cpp/issues/1104. Will see what happens...
If it matters, I've created a separate github repo for porting Bullet to GDextension.
Maybe then suggest a merge into the main repository? To include your work in the engine? The developers did not want to waste time implementing Bullet, but since a good person did everything for them, maybe they will take it as the basis of the engine?
I've added the suggestion to the discussions.
https://github.com/godotengine/godot-proposals/discussions/6687#discussioncomment-5602799
Engardium My personal favorite quote in the conversation is "By giving Godot users no other way, it's forcing evolution for the best, with some pain along the way."
I would just add "Or it makes Godot users switch to Unreal and give up Patreon support" 
Which is indeed evolution for the best in some sense
Awesome, thanks for making the integration! I, for one, can't wait for an additional Physics library option other than Godot's Physics for 3D.
Also be sure to check Godot Jolt which is a GDExtension in progress for Jolt in Godot. It's almost fully working. So you also might get ideas from the code, if needed: https://github.com/godot-jolt/godot-jolt
alfredbaudisch Also be sure to check Godot Jolt which is a GDExtension in progress for Jolt in Godot. It's almost fully working. So you also might get ideas from the code, if needed: https://github.com/godot-jolt/godot-jolt
Yea, thanks for the hint! I'm aware of Godot-jolt. It's absolutely great!
In the case of making a GDextension out of Bullet it seems like it's a bug in the command "godot --dump-extension-api extension_api.json" which is supposed to generate all the API. Specifically for PhysicsServer3D it doesn't export several enums which are needed for Bullet to work. The devs have already assigned it a bug flag, see https://github.com/godotengine/godot-cpp/issues/1104.
@"alfredbaudisch"#p110287 oh but notice how I just said "with Bullet/Jolt" and not Godot's Physics itself
Absolutely! IMHO it's much less of a pain to rely on something tested. Despite of all the arguments the devs' position 1) claim lack of contributors and at the same time 2) developing custom physics engine from scratch still does not line up in my head
ive also found physics unreliable in godot 4. some collisions just dont get correctly detected.
is this because of godot physics? if so, is bullet physics so much better?
DJM is this because of godot physics? if so, is bullet physics so much better?
Bullet is battle-proven, with many shipped titles.
GTAIV and Read Dead between them:
Bullet is an open-source 3D physics library produced by Erwin Coumans, featuring rigid and soft body physics, 3D collision detection and multiple 3D modelling/animation software plugins. The library has been incorporated into the Rockstar Advanced Game Engine, which has been used by Grand Theft Auto IV and Red Dead Redemption.
Given the position of the developers, I see the only way to make a module from Bullet. We are waiting for the correction of the error that does not allow this. I hope they fix this at least soon. Until this happens, I beg the Z80 to support us with new versions with corrections and not give up this good cause. You are saving the community at this difficult time.
Hello everyone!
I've just fixed a bug in Bullet physics support for Godot4 and upgraded to the most recent 4.0.3-stable except two files viewport.h/viewport.cpp which in some of my projects make viewport texture to not work.
Please find the code snapshot and windows-64bit binaries here https://github.com/z80/ignition/releases/tag/commit_cd4f85694.
z80 Hi appreciate you working on this, I've managed to pull out the Bullet Physics stuff from your repo into the latest builds for Godot for my own project however I noticed an odd issue with the implementation.
The capsule colliders seem to not be working correctly, They seem to apply an additional invisible barrier that doesn't seem to show in the debug collisions. It was pretty easy to get this to repeat I also built your instance of the engine just in case it was limited to just my version and it seems like the issue is present in both. I'm guessing this is something to do with margins since the collision debug seems to show the capsule scaled correctly etc.
Steps I did to see this issue:
Any ideas on how to solve this issue? Also is there any updates on moving this stuff to GDExtensions it seems like your bug report hasn't been updated in awhile?
Xanz I actually managed to fix this issue but posting the solution in case anyone else is attempting to use the implementation.
So there is two issues, In Godot 4 the default capsule orientation is upright rather than aligned along the Z axis. Since the implementation uses the code from Godot 3.5 the alignment is still aligned to the Z axis instead of upright. You can fix this in the bullet code so that instead of creating and returning a BtCapsuleShapeZ you return a BtCapsuleShape, This will fix the alignment issues and the strange invisible force.
Alongside this another issue encountered is that the capsule height is no longer aligned with the debug widgets heights and just the general capsule height as it seems like Godot 4 expects that to be the exact height. This causes an issue as bullet expects a half height(This is just knowledge from implementing bullet in a custom engine so could be slightly incorrect but seems to resolve this issue).
This will cause issues with capsules appearing like they are floating or just general strange height related issues. To solve this simply divide the height received in the CapsuleBulletShape::setup method by 2(You could do this earlier in the callstack but it seems like a sensible place to do it as it keeps it within the bullet module). This will give you the half height which is what bullet expects.
Good luck to anyone else using this!
Xanz
Ok, I've changed it from
btCapsuleShapeZ *ShapeBullet::create_shape_capsule(btScalar radius, btScalar height) {
return bulletnew(btCapsuleShapeZ(radius, height));
}
to
btCapsuleShape *ShapeBullet::create_shape_capsule(btScalar radius, btScalar height) {
// Bullet expects half height.
return bulletnew(btCapsuleShape(radius, height*0.5));
}
It seems like it does the job. Thank you again for the bug detection and how to fix instruction! That's open source in action!
The code with the fix applied: https://github.com/z80/ignition/tree/bullet_godot_4_1bf56109f6
Code snapshot and binaries for Windows: https://github.com/z80/ignition/releases/tag/bullet_godot_4_1bf56109f6
Bullet physics binding is upgraded to Godot-4.1.1-stable.
Source code: [https://github.com/z80/ignition/tree/godot_4.1.1_bullet_physics_1bf56109f6]https://github.com/z80/ignition/tree/godot_4.1.1_bullet_physics_1bf56109f6)
Windows binaries:
https://github.com/z80/ignition/releases/tag/godot_4.1.1_bullet_physics_1bf56109f6
nice stuff.
Good to see there is another alternative to vanilla engine physics.(The other alternative is jolt3d)
No offense intended, but the physics3d in 4.0 is a piece of ****, especially performance and stability wish. A few convex shapes with like 50 vertices colliding each other will cause the physics time jumping from 16ms to 1000+
Upgraded Bullet physics support to Godot 4.1.2-stable.
Source code: https://github.com/z80/ignition/tree/godot_4.1.2_stable_960ccf8fe9
Windows binaries: https://github.com/z80/ignition/releases/tag/godot_4.1.2_stable_960ccf8fe9
