I have a problem - I am trying to do a very basic thing: something similar to TPP view, with BOX as a character. So basically I've created a box as rigid body, then I update it (rotate) and display the scene with camera set behind it's back (looking at it).
What would I expect is that I will always see the box in one view (ie. always see it's back side or two of it's corners) and the world would rotate around it. What I see is that everything rotates - including the box (which shouldnt) - it's still centered in the view, but slightly rotates as the world rotates (which is wrong).
The code is very simple -it's just some example code stitched together, but I spent two days trying to solve that mystery and I am going mental. I would be very happy if someone could help. thanks!
I create box rigid body like this:
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btTransform startTransform;
startTransform.setIdentity ();
startTransform.setOrigin ( btVector3( 0.0, 3.0, 0.0 ) );
fallShapeBox = new btBoxShape( btVector3( 3.0, 3.0, 3.0 ) );
fallMotionStateBox = new btDefaultMotionState( startTransform );
fallShapeBox->calculateLocalInertia( 1.0, fallInertia2 );
btRigidBody::btRigidBodyConstructionInfo fallRigidBodyCIBox( 1.0, fallMotionStateBox, fallShapeBox );
fallRigidBodyBox = new btRigidBody( fallRigidBodyCIBox );
fallRigidBodyBox->setSleepingThresholds ( 0.0, 0.0 );
fallRigidBodyBox->setAngularFactor ( 0.0 );
fallRigidBodyBox->setActivationState( DISABLE_DEACTIVATION );
dynamicsWorld->addRigidBody( fallRigidBodyBox );
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btTransform xform;
xform = fallRigidBodyBox->getWorldTransform();
btVector3 up = xform.getBasis()[1];
btVector3 backward = xform.getBasis()[2];
up.normalize ();
backward.normalize ();
m_cameraTargetPosition = xform.getOrigin();
m_cameraPosition = m_cameraTargetPosition + up * ( 6.0 ) - backward * 24.0;
btScalar m[16];
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
gluLookAt( m_cameraPosition[0], m_cameraPosition[1], m_cameraPosition[2],
m_cameraTargetPosition[0], m_cameraTargetPosition[1], m_cameraTargetPosition[2],
m_cameraUp.getX(), m_cameraUp.getY(), m_cameraUp.getZ() );
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mBulletSetCamera();
const int numObjects = dynamicsWorld->getNumCollisionObjects();
btVector3 wireColor( 1, 0, 0 );
for ( int i = 0; i < numObjects; i++ )
{
btCollisionObject* colObj = dynamicsWorld->getCollisionObjectArray()[i];
btRigidBody* body = btRigidBody::upcast( colObj );
if ( body && body->getMotionState() )
{
btDefaultMotionState* myMotionState = ( btDefaultMotionState* )body->getMotionState();
myMotionState->m_graphicsWorldTrans.getOpenGLMatrix( m );
rot = myMotionState->m_graphicsWorldTrans.getBasis();
}
else
{
colObj->getWorldTransform().getOpenGLMatrix( m );
rot = colObj->getWorldTransform().getBasis();
}
btVector3 wireColor( 1.f, 0.0f, 0.5f ); //wants deactivation
if ( i&1 ) wireColor = btVector3( 0.f, 1.0f, 1.f );
btVector3 aabbMin, aabbMax;
dynamicsWorld->getBroadphase()->getBroadphaseAabb( aabbMin, aabbMax );
aabbMin -= btVector3( 1e30, 1e30, 1e30 );
aabbMax += btVector3( 1e30, 1e30, 1e30 );
glPushMatrix();
glMultMatrixf( m );
switch ( colObj->getCollisionShape()->getShapeType() )
{
case BOX_SHAPE_PROXYTYPE:
{
const btBoxShape* boxShape = static_cast<const btBoxShape*>( colObj->getCollisionShape() );
btVector3 halfExtent = boxShape->getHalfExtentsWithMargin();
glScaled( 2*halfExtent[0], 2*halfExtent[1], 2*halfExtent[2] );
glutSolidCube( 1.0 );
//useWireframeFallback = false;
break;
}
case SPHERE_SHAPE_PROXYTYPE:
//glMultMatrixf( m );
const btSphereShape* sphereShape = static_cast<const btSphereShape*>( colObj->getCollisionShape() );
float radius = sphereShape->getMargin();//radius doesn't include the margin, so draw with margin
glutSolidSphere( radius, BALLQUALITY, BALLQUALITY );
break;
default:
break;
}
glPopMatrix();
}
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btScalar m[16];
if ( dir == ROTATER )
m_angle += 3.1415f / 360;
if ( dir == ROTATEL )
m_angle -= 3.1415f / 360;
btTransform xform;
xform = fallRigidBodyBox->getWorldTransform();
xform.setRotation ( btQuaternion ( btVector3( 0.0, 1.0, 0.0 ), m_angle ) );
btVector3 linearVelocity = fallRigidBodyBox->getLinearVelocity();
btScalar speed = fallRigidBodyBox->getLinearVelocity().length();
btVector3 forwardDir = xform.getBasis()[2];
forwardDir.normalize ();
btVector3 walkDirection = btVector3( 0.0, 0.0, 0.0 );
if ( dir == NORTH )
walkDirection += forwardDir;
if ( dir == SOUTH )
walkDirection -= forwardDir;
if ( ( dir == NORTH ) || ( dir == SOUTH ) )
if ( speed < 15.0f )
{
linearVelocity *= btScalar( 2.2 );
btVector3 velocity = linearVelocity + walkDirection * 3;
fallRigidBodyBox->setLinearVelocity ( velocity );
}
fallRigidBodyBox->getMotionState()->setWorldTransform ( xform );
fallRigidBodyBox->setCenterOfMassTransform ( xform );
fallRigidBodyBox->activate( true );
