Jorrit Rouwe

Lead Game Tech Programmer at Guerrilla Games, creator of the Jolt Physics library. @[email protected], @jrouwe.bsky.social

[Jorrit Rouwe @jrouwe]

@dzmitryj_ Unfortunately the GPU raycasts never made it because the overhead of going to the GPU and back was too much at the time. Someday they will be back though!

[Jorrit Rouwe @jrouwe]

Jolt Physics just hit 10K GitHub stars! What started in 2014 as a CPU vs GPU ray casting experiment became a full physics engine in 2021. Seeing what you’re building with it is amazing. Thank you!

[Jorrit Rouwe @jrouwe]

@Ademola_4life You might be running out of memory. By default it uses a fixed memory pool which you can configure here: https://t.co/3wiYjjr3YR

[Jorrit Rouwe @jrouwe]

@BattleAxeVR No IK is not part of Jolt (I would categorize it under 'animation' rather than 'physics')

[Jorrit Rouwe @jrouwe]

@BattleAxeVR You have to apply gravity, but the ground check is included. It's only a couple of lines of code: https://t.co/3WCZvBxrUp

[Jorrit Rouwe @jrouwe]

@BattleAxeVR Mirroring works too, see all the samples in the ScaledShape folder.

[Jorrit Rouwe @jrouwe]

@BattleAxeVR Yes, adding automatic convex decomposition is on my rather large to do list.

[Jorrit Rouwe @jrouwe]

@BattleAxeVR It references your original shape, so no triangles are duplicated. If you use non-uniform scale on CompoundShapes then it may create a new CompoundShape, but whatever is in the CompoundShape will not be duplicated.

[Jorrit Rouwe @jrouwe]

@BattleAxeVR About the convex hulls: PhysX is using 'convex decomposition' (creating multiple convex hulls). Jolt only creates a single convex hull. You'll need another library to do the decomposition, e.g. https://t.co/mv2YWonX2O

[Jorrit Rouwe @jrouwe]

@BattleAxeVR There is the JoltViewer, but it doesn't connect over a socket like PVD does, it reads from a file that you can produce with DebugRendererRecorder. I usually just draw physics object in the game window using the DebugRenderer.

[Jorrit Rouwe @jrouwe]

@BattleAxeVR What's wrong with the convex hull generation code? Send me the points that cause issues and I'll take a look. (Note that I did a tweak to the generator this week)

[Stellarica Interactive @Stellarica_io]

Early prototype of a real-time, physics-driven car deformation system built in Godot on top of Jolt Physics.
All deformation is computed at runtime (no pre-baked damage), and it runs in real time on older mobile hardware.
Video: https://t.co/tv9IKXAjpJ

[Jorrit Rouwe @jrouwe]

@mannyn83 I have to still make an option for DX12 to directly load compiled shaders instead of compiling hlsl on the fly.

[Jorrit Rouwe @jrouwe]

A sneak peak of what I've been working on: A strand based hair system for Jolt Physics (WIP): https://t.co/jAGoFxJ0HX

[Jorrit Rouwe @jrouwe]

@mannyn83 > Does Jolt want to create the program from it's own shader source?
CreateComputeShader(const char *inName, ...) passes in a name. Where you get the shader from is up to you. The default DX12 implementation uses mShaderLoader to load hlsl, Vulkan/Metal load compiled shaders.

[Jorrit Rouwe @jrouwe]

@mannyn83 > Thanks, one thing I noticed is the Map/Unmap which is not so great for WebGPU
Ok, I'll think about that.

[Jorrit Rouwe @jrouwe]

@mannyn83 I did attempt to make that abstraction in a way that is hopefully easily integrated (with DX12, Vulkan and Metal implementations): https://t.co/iLohd1Io3t. Let me know what you think of it.

[Jorrit Rouwe @jrouwe]

@datgame The 4ms is measured on GPU, the CPU part is about 0.1 ms (broad phase collision detection + setting up compute jobs). And it is indeed one way: physics objects affect the hair, but the hair doesn't affect the physics objects.

[Jorrit Rouwe @jrouwe]

@datgame If you're talking about how fast it runs: Currently 4 ms on my 5070 Ti laptop GPU with the sim running at 360 Hz. I have to further optimize it though.

[Jorrit Rouwe @jrouwe]

@SubstrataVr I've created support for DX12, Vulkan and Metal. Didn't do OpenGL, but it would certainly be possible.