Search found 85 matches

by hyyou
Thu May 10, 2018 2:54 am
Forum: General Bullet Physics Support and Feedback
Topic: Detection of child shape indices in a collision for a compound shape
Replies: 5
Views: 211

Re: Detection of child shape indices in a collision for a compound shape

^ Because of the uninitialized value, I have to remember type of the shape in my own code. Great answer, drleviathan! ... It is also consistent with what I noticed. To reply OP's email, yes, I believe query the "index" is the best way. It is probably the only way. AFAIK, Bullet's API doesn't provide...
by hyyou
Sun Apr 29, 2018 2:18 am
Forum: General Bullet Physics Support and Feedback
Topic: Minimalist game loop with tunneling
Replies: 7
Views: 299

Re: Minimalist game loop with tunneling

I am out of idea.

I have never faced such problem for the built-in btBoxShape.
Perhaps, it is limitation of btBvhTriangleMeshShape or its margin.
(more info about margin) https://www.youtube.com/watch?v=BGAwRKPlpCw
by hyyou
Fri Apr 06, 2018 2:12 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape tunneling
Replies: 9
Views: 394

Re: btBvhTriangleMeshShape tunneling

I believe it is very fast, but not sure if it is too fast.

I just noticed that, at some time-steps, it looks like stack of box simulation.
Try to enable "SOLVER_RANDMIZE_ORDER". (http://bulletphysics.org/mediawiki-1.5. ... SolverInfo)

I am curious if it helps.
by hyyou
Thu Apr 05, 2018 2:08 am
Forum: General Bullet Physics Support and Feedback
Topic: btBvhTriangleMeshShape tunneling
Replies: 9
Views: 394

Re: btBvhTriangleMeshShape tunneling

(I will avoid to repeat what drleviathan already mentioned.) Hmm... I feel that the dropping boxs move quite fast. I am curious. How much are their max speed? There is a rumor that the middle parameter of stepSimulation() should be 1. (https://stackoverflow.com/a/21273467) I didn't verify it, but I ...
by hyyou
Tue Apr 03, 2018 12:33 pm
Forum: General Bullet Physics Support and Feedback
Topic: motion state and others
Replies: 5
Views: 473

Re: motion state and others

Thank a lot, drleviathan, for very rich answer!
I gain extra knowledge from your gravity and btConvexHullShape part.
I will follow you everywhere. XD
by hyyou
Mon Apr 02, 2018 1:57 am
Forum: General Bullet Physics Support and Feedback
Topic: motion state and others
Replies: 5
Views: 473

Re: motion state and others

- gravity - what is the proper way of setting correct value of it? To avoid any issue, I set it as (0,0,0) and apply gravity impulse every time-step instead. btQuaternion(0.0f, 0.0f, 0.0f, 1), I read http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-17-quaternions/ btVector3(0, 0, 0) /...
by hyyou
Sat Mar 31, 2018 2:16 am
Forum: General Bullet Physics Support and Feedback
Topic: Mouse picking, rayTest
Replies: 2
Views: 142

Re: Mouse picking, rayTest

Whoo.... the code is so long. Sorry for not read it. I stuck with the same issue. Here is how I solved :- 1. Erase all Graphics code. Erase all mouse-related code. 2. Create empty world. 3. Create 1 very simple btBoxShape & 1 btRigidbody with all 1 mask at position (0,0,0). 4. Try to ray test only 1...
by hyyou
Sat Mar 24, 2018 2:06 am
Forum: General Bullet Physics Support and Feedback
Topic: Integrate simulator with Bullet
Replies: 5
Views: 227

Re: Integrate simulator with Bullet

Thank drleviathan, for the great answer!

On topic:-

OgreBullet (http://wiki.ogre3d.org/OgreBullet) is a popular example.
It aims to integrate a node-based graphic engine (Ogre) with Bullet.
OP may get some neat idea from it. I have never used it though.
by hyyou
Thu Mar 22, 2018 3:52 pm
Forum: General Bullet Physics Support and Feedback
Topic: Integrate simulator with Bullet
Replies: 5
Views: 227

Re: Integrate simulator with Bullet

I use 1 body = 1 node.
Yes, there are still a lot of (fun) work.
by hyyou
Thu Mar 08, 2018 4:00 am
Forum: General Bullet Physics Support and Feedback
Topic: How to move a character? FPS
Replies: 2
Views: 342

Re: How to move a character? FPS

(late reply) I don't know much about Bullet's camera. Bullet's Physics position are usually world-coordinate. By the way, I believe the Graphics part of Bullet is just there for debugging purpose + show-case. If you want to make a FPS, you may also want to code Graphics yourself (raw OpenGl) , or us...
by hyyou
Thu Mar 08, 2018 3:32 am
Forum: General Bullet Physics Support and Feedback
Topic: Predict whether a step will occur
Replies: 4
Views: 211

Re: Predict whether a step will occur

Can you call stepSimulation(customFixedValue) only when "total >= doStepValue" instead?
by hyyou
Mon Mar 05, 2018 9:54 am
Forum: General Bullet Physics Support and Feedback
Topic: get force from collision impulse : m_appliedImpulse always = 0
Replies: 0
Views: 117

get force from collision impulse : m_appliedImpulse always = 0

How to get force from collision impulse? I used a recommended approach. It doesn't work. (i.e. just almost work) Let's say there are 2 bodies. Assume that they collide each other at t=1. t=1: The contact is created but m_appliedImpulse = 0. btWorld->stepSimulation(...); //..... iterating manifold .....
by hyyou
Tue Feb 13, 2018 6:38 am
Forum: General Bullet Physics Support and Feedback
Topic: performDiscreteCollisionDetection (update manifold) for only a few bodies (ghost?)
Replies: 9
Views: 857

Re: performDiscreteCollisionDetection (update manifold) for only a few bodies (ghost?)

Hmm.... I also tried to use it a few years ago but failed .... so I always assume that Ghost-and-friend are quite useless. :lol: Unfortunately, I have a lot of objects in the world (100-1000). My ultimate objective is to simulate a compound shape with radar :- bullet15.jpg However, Bullet doesn't su...
by hyyou
Sun Feb 11, 2018 8:52 am
Forum: General Bullet Physics Support and Feedback
Topic: Jbullet: NPE when removing body with TRIANGLE_MESH shape.
Replies: 3
Views: 2124

Re: Jbullet: NPE when removing body with TRIANGLE_MESH shape.

Should a rigid body always be re-added to the world after setting the collision shape I don't know about Java port, but this is a well-known Bullet (C++) limitation/restriction of usage. A workaround is to encapsulate it. I check change-of-shape every time-step. Reference (C++) : https://pybullet.o...
by hyyou
Sun Feb 11, 2018 3:08 am
Forum: General Bullet Physics Support and Feedback
Topic: performDiscreteCollisionDetection (update manifold) for only a few bodies (ghost?)
Replies: 9
Views: 857

Re: performDiscreteCollisionDetection (update manifold) for only a few bodies (ghost?)

Wow! A complete code. Thank drleviathan, again XD. For science, I took the liberty of running your code, and post the result :- bullet14.jpg There are 2 aspects that worry me :- - At 002, it shows "bug?". - If stepSimulation() is removed, numOverlaps at 001 will = 0 (more wrong). My objective of usi...