SetLimits for ball joints bug

[shadmar]

If you test ball joints they are wierd

According to the docs it should be SetLimits(cone,twist), however cone seems to be set in the last parameter.

And twist doesn't seem to work, however setting a high value, seems to break cone.?

 

Test :

 

Copy/paste into any App.lua

 

camera=Camera:Create()

camera:SetPosition(0,2,-5)

 

ground = Model:Box(20,1,20)

local shape=Shape:Box(0,0,0,0,0,0,20,1,20)

ground:SetShape(shape)

ground:SetMass(0)

 

 

box1 = Model:Box()

box1:SetPosition(0,1.5,0)

box1:SetColor(1,0,0)

local shape=Shape:Box()

box1:SetShape(shape)

box1:SetMass(20)

 

box2=box1:Instance()

box2:SetColor(0,1,0)

box2:SetPosition(0,3,0)

box2:SetMass(1)

 

cone=0

twist=45

 

joint=Joint:Ball(0,2,0,box1,box2)

joint:SetLimits(cone,twist)

joint:EnableLimits()

 

box2:AddTorque(200,200,200)

[Admin]

You're right, that is very strange. I reported it here:

http://newtondynamics.com/forum/viewtopic.php?f=12&t=7770

 

function App:Start()
    self.angle=45
 
    self.window = Window:Create()
    self.context = Context:Create(self.window)
    self.world = World:Create()
 
    piv = Pivot:Create()
 
    camera=Camera:Create(piv)
    camera:SetPosition(0,2,-5)
    camera:SetDebugPhysicsMode(true)
 
    ground = Model:Box(20,1,20)
    local shape=Shape:Box(0,0,0,0,0,0,20,1,20)
    ground:SetShape(shape)
    ground:SetMass(0)
 
    box1 = Model:Box()
    box1:SetPosition(0,1.5,0)
    box1:SetColor(1,0,0)
    local shape=Shape:Box()
    box1:SetShape(shape)
    box1:SetMass(20)
 
    box2=box1:Instance()
    box2:SetColor(0,1,0)
    box2:SetPosition(0,3,0)
    box2:SetMass(1)
 
    cone=0
    twist=45
 
    joint=Joint:Ball(0,2,0,box1,box2)
    joint:SetLimits(cone,twist)
    joint:EnableLimits()
 
    box2:AddTorque(2000,2000,0)
 
    return true
end
 
function App:Loop()
 
if self.window:KeyHit(Key.Escape) then return false end
piv:Turn(0,1,0)
	    Time:Update()
	    self.world:Update()
	    self.world:Render()
	    self.context:Sync()
	    return true
end

[Josh]

I see. The ball joint matrix needs to indicate the pin direction. This will work in the update next week:

#include "App.h"

using namespace Leadwerks;

App::App() : window(NULL), context(NULL), world(NULL), camera(NULL) {}

App::~App() { delete world; delete window; }

float angle=25;
Joint* joint;

bool App::Start()
{
    window = Window::Create();
    context = Context::Create(window);
    world = World::Create();
    camera = Camera::Create();
    camera->Move(0,0,-4);
    Light* light = DirectionalLight::Create();
    light->SetRotation(35,35,0);

        Model* ground = Model::Box(20,1,20);
    Shape* shape=Shape::Box(0,0,0,0,0,0,20,1,20);
    ground->SetShape(shape);
    ground->SetMass(0);

   Model* box1 = Model::Box();
       box1->SetPosition(0,1.5,0);
       box1->SetColor(1,0,0,1);
       shape=Shape::Box();
       box1->SetShape(shape);
       box1->SetMass(20);

       Model* box2=(Model*)box1->Instance();
       box2->SetColor(0,1,0,1);
       box2->SetPosition(0,3,0);
       box2->SetMass(1);

       float cone=45;
       float twist=0;

       joint=Joint::Ball(0,2,0,box1,box2);
       joint->SetLimits(cone,twist);
       joint->EnableLimits();

       box2->AddTorque(200,200,200);

    return true;
}

bool App::Loop()
{
    if (window->Closed() || window->KeyDown(Key::Escape)) return false;

    if (window->KeyDown(Key::Up)) angle+=1.0;
    if (window->KeyDown(Key::Down)) angle-=1.0;
    joint->SetAngle(angle);
    if (window->KeyHit(Key::Space))
    {
		    if (!joint->MotorEnabled())
		    {
				    joint->EnableMotor();
		    }
		    else
		    {
				    joint->DisableMotor();
		    }
    }

    Time::Update();
    world->Update();
    world->Render();
    context->Sync();

    return true;
}