Bug ? Crash when callback number more than 960 for customfilter.

[Ronniko]

bool MyCustomFilter(b3ShapeId shapeIdA, b3ShapeId shapeIdB, void* context)
{
//MyGame* myGame = context;
//return myGame->WantsCollision(shapeIdA, shapeIdB);
return false;// if return true, work fine. not crash.
}

enum MyCategories
{
PLAYER = 0x00000002,
MONSTER = 0x00000004,
};

b3ShapeDef playerShapeDef = b3DefaultShapeDef();

playerShapeDef.filter.categoryBits = PLAYER;

// Players collide with monsters, but not with other players
playerShapeDef.filter.maskBits = MONSTER;

playerShapeDef.enableCustomFiltering = true;
b3World_SetCustomFilterCallback(myWorldId, MyCustomFilter, NULL);

[Ronniko]

I get crash(after 12 secs working my program) ACCESS VIOLATION on : mov eax,[ebp+eax*4-1008h] Exception addr: 749CED3Bh in Box3D.dll

And not work PreSolve callback. If i return always false from MyCustomFilter function.

[erincatto]

You are setting the context to null, not to your game.

b3World_SetCustomFilterCallback(myWorldId, MyCustomFilter, NULL);

[Ronniko]

How looking void* context function ? What parameters get function ?

And i Do have to do for all bodys this or not ?
b3BodyDef.userData = &some function

[Ronniko]

I do and get the same crash.
void myContext() { };
b3World_SetCustomFilterCallback(myWorldId, &MyCustomFilter, &myContext);

[erincatto]

I recommend spending some time learning about pointers and lifetime in C/C++.

https://en.cppreference.com/cpp/language/lifetime

[Ronniko]

Why box3D function not checking valid shapeIdA, b3ShapeId shapeIdB, void* context ?
If valid than call user function MyCustomFilter.
If not valid , not call MyCustomFilter.
This is the inner kitchen box3D, not user.

It's more secure.
And any way we must do checking valid, so why not do it in box3d function.

[erincatto]

There is no way for me to check if your context pointer if valid. It is opaque to Box3D.

From your code above it looks like your context has gone out of scope because it was declared on the stack.

Feel free to provide code sample that reproduces the bug.

[Ronniko]

In docs says.
bool MyCustomFilter(b3ShapeId shapeIdA, b3ShapeId shapeIdB, void* context)
{
MyGame* myGame = context;
return myGame->WantsCollision(shapeIdA, shapeIdB);//this call class function WantsCollision ?
}

Where is looking class MyGame ? I needed looking all functions(vtblInterfaceTab) class MyGame.
I not found MyGame class in samples and sources, headers box3D.

Or MyGame class it simple some user class for just example ?

[erincatto]

MyGame is a user provided object. You can look at the BenchmarkSensor sample to see how to use it.