Search found 51 matches

by d3x0r
Mon Oct 19, 2015 8:17 am
Forum: General Bullet Physics Support and Feedback
Topic: Technical questions about code
Replies: 0
Views: 1950

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 address.... is there so...
by d3x0r
Sun Oct 18, 2015 3:11 pm
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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...
by d3x0r
Sun Oct 18, 2015 12:31 pm
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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._b + ...
by d3x0r
Sun Oct 18, 2015 11:36 am
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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...
by d3x0r
Sat Oct 17, 2015 9:15 am
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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...
by d3x0r
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: 1836

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...
by d3x0r
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: 1836

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...
by d3x0r
Fri Oct 16, 2015 2:52 pm
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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...
by d3x0r
Thu Oct 15, 2015 8:25 am
Forum: General Bullet Physics Support and Feedback
Topic: While porting this I found this...
Replies: 19
Views: 4377

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_hitFraction ...
by d3x0r
Thu Oct 15, 2015 12:35 am
Forum: General Bullet Physics Support and Feedback
Topic: Dynamic btHeightfieldTerrainShape causing jittered collision
Replies: 6
Views: 1985

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...
by d3x0r
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: 3839

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.
by d3x0r
Sat Oct 10, 2015 2:13 am
Forum: General Bullet Physics Support and Feedback
Topic: btVoxelShape for grid-based world support
Replies: 4
Views: 2964

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 ...
by d3x0r
Thu Oct 08, 2015 8:47 am
Forum: General Bullet Physics Support and Feedback
Topic: btVoxelShape for grid-based world support
Replies: 4
Views: 2964

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...
by d3x0r
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: 3839

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>...
by d3x0r
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: 2967

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...