Search found 51 matches
- Mon Oct 19, 2015 8:17 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Technical questions about code
- Replies: 0
- Views: 3216
Technical questions about code
In BulletCollision/BroadphaseCollision btBroadphaseProxy.h in class btBroadphasePairSortPredicate is this expression... && a.m_algorithm > b.m_algorithm m_algorithm is " mutable btCollisionAlgorithm* m_algorithm;" There's no operator> for this... so it's just comparing memory addre...
- Sun Oct 18, 2015 3:11 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
Re: While porting this I found this...
And here are the results of my tests. What is interesting is that the new method is about the same as the copy in the optimized case, but not the unoptimized. There was noise in the results and since the numbers were so close I ran the comparison several times and found that the optimized new still...
- Sun Oct 18, 2015 12:31 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
Re: While porting this I found this...
Another performance issue (at a cost of ease of development for sure) class Vector{ float _a,_b,_c; public: inline Vector( float a, float b, float c){ _a = a; _b = b; _c = c; } inline Vector( ){ _a = 0; _b = 0; _c = 0; } inline Vector operator+(const Vector& v1) { return Vector( v1._a + _a, v1._...
- Sun Oct 18, 2015 11:36 am
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
Re: While porting this I found this...
For performance it's faster to assign than to use constructor class Vector{ float _a,_b,_c; public: inline Vector( float a, float b, float c){ _a = a; _b = b; _c = c; } }; Vector Zero(0,0,0); this takes almost twice as long as just assignment Vector v(0,0,0); Vector v2 = Zero; creating a zero vector...
- Sat Oct 17, 2015 9:15 am
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
Re: While porting this I found this...
Neib = neighbor! Ok. --- re FLT_MIN... my bad; C# has double.MaxValue and double.MinValue so I didn't look and thought MIN was equivalent... since there's FLT_EPSILON which is also FLT_MIN; while .NET's double.Epsilon is the minimum non zero value. but isn't minimum and maximum float off by +/-1 lik...
- Sat Oct 17, 2015 4:47 am
- Forum: General Bullet Physics Support and Feedback
- Topic: How far-fetched is 4D collision detection?
- Replies: 5
- Views: 5192
Re: How far-fetched is 4D collision detection?
... from that link... The − sign instead of a + sign in front of the t2 in the spacetime separation formula s2=−t2+x2+y2+z2 means that time t can often be treated mathematically as if it were an imaginary spatial dimension. That is, t=iw, where i is the square root of −1 and w is a “fourth spatial c...
- Fri Oct 16, 2015 3:08 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: How far-fetched is 4D collision detection?
- Replies: 5
- Views: 5192
Re: How far-fetched is 4D collision detection?
A hypersphere or hypercube or other hyper primitive I'd think would remain convex in all rotations. Though with time as a representation, I don't know that it would be that useful... a cube is here then it's there... at some later point it returns to 'here' does that mean it collided? does it matter...
- Fri Oct 16, 2015 2:52 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
Re: While porting this I found this...
Okay true... I triple checked it and thought it was the same. ---- lots of places use -FLT_MAX instead of FLT_MIN. there's also several places that use 1e30 instead of BT_LARGE_FLOAT as in.. btScalar planeEq = 1e30f; or btScalar minDist = -1e30f; Many places define a EPSILON instead of using SIMD_EP...
- Thu Oct 15, 2015 8:25 am
- Forum: General Bullet Physics Support and Feedback
- Topic: While porting this I found this...
- Replies: 19
- Views: 46386
While porting this I found this...
This is in struct ClosestRayResultCallback..... m_hitPointWorld.setInterpolate3 clears the value set in the IF above... virtual btScalar addSingleResult(LocalRayResult& rayResult,bool normalInWorldSpace) { //caller already does the filter on the m_closestHitFraction btAssert(rayResult.m_hitFract...
- Thu Oct 15, 2015 12:35 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Dynamic btHeightfieldTerrainShape causing jittered collision
- Replies: 6
- Views: 13019
Re: Dynamic btHeightfieldTerrainShape causing jittered colli
I had similar issues with just a ball colliding with a fixed surface; that the correcting impulse seemed to be much larger than one would expect. The engine I'm sure isn't doing anything other than realizing that the thing has collided and generating a impulse to push it away. 1) does it change if y...
- Sat Oct 10, 2015 2:59 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Compile Bullet 2.83 on MinGW [HELP]
- Replies: 5
- Views: 7044
Re: Compile Bullet 2.83 on MinGW [HELP]
A pretty old one?
gcc.exe (GCC) 4.8.1
the _TRUNCATE issue is becuase mingw refuses to maintain their s***.
So that would be fixed with mingw64...
the reset is because windows.
gcc.exe (GCC) 4.8.1
the _TRUNCATE issue is becuase mingw refuses to maintain their s***.
So that would be fixed with mingw64...
the reset is because windows.
- Sat Oct 10, 2015 2:13 am
- Forum: General Bullet Physics Support and Feedback
- Topic: btVoxelShape for grid-based world support
- Replies: 4
- Views: 7461
Re: btVoxelShape for grid-based world support
The engine I'm basing my ideas from is BlackVoxel (www.blackvoxel.com) They track their world in sectors of (16x64x16) (tall boxes where x,z is ground); think I'm going to rescale that to 32x32x32 blocks (still only 15 bits)... but your position in the world is basically first divided by the sector ...
- Thu Oct 08, 2015 8:47 am
- Forum: General Bullet Physics Support and Feedback
- Topic: btVoxelShape for grid-based world support
- Replies: 4
- Views: 7461
Re: btVoxelShape for grid-based world support
Well this looks interesting :) So many questions.... What I would like to have is a btVoxelShape that has different units. The ground 1.0 is fine, but I'd like to have a (for example) 1.3 and a 0.25 type of movable voxel body. How much work to extend to support independant voxel bodies colliding wit...
- Thu Oct 08, 2015 7:53 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Compile Bullet 2.83 on MinGW [HELP]
- Replies: 5
- Views: 7044
Re: Compile Bullet 2.83 on MinGW [HELP]
/* _TRUNCATE */ #if !defined(_TRUNCATE) #define _TRUNCATE ((size_t)-1) #endif But that won't fix all the issues... --- a/examples/ThirdPartyLibs/Gwen/Macros.h +++ b/examples/ThirdPartyLibs/Gwen/Macros.h @@ -4,6 +4,7 @@ #define GWEN_MACROS_H #include <stdlib.h> #include <stdarg.h> +#include <stdio.h>...
- Sun Jan 13, 2013 2:41 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Demos are 10x slower than the real world
- Replies: 5
- Views: 5841
Re: Demos are 10x slower than the real world
it all actually pretty realistic because the objects are actually really big given that a unit of 1 is 1 meter; In my current simulation gravity is set at 9800.0 which is mm, and all of my objects are ping ping balls at like 44mm. but when it was at 9.8 it was really slow, but then I realized that's...