// tanAcceleration returns the tangential acceleration of the frame in
// world space.
Vector Physics::tanAcceleration() const{
return cross(angularAcceleration(),position())-tanAccelerationReference();
}
void Item::UpdatePhysics(float dt)
{
vec3 acceleration = (m_gravityDirection * 9.81f) * 4.0f;
// Integrate velocity
m_velocity += acceleration * dt;
// Integrate angular velocity and rotation
vec3 angularAcceleration(0.0f, 0.0f, 0.0f);
m_angularVelocity += angularAcceleration * dt;
m_rotation += m_angularVelocity * dt;
if (m_worldCollide)
{
int blockX, blockY, blockZ;
vec3 blockPos;
// Check collision
{
vec3 velocityToUse = m_velocity;
vec3 velAmount = velocityToUse*dt;
vec3 pNormal;
int numberDivision = 1;
while (length(velAmount) >= 1.0f)
{
numberDivision++;
velAmount = velocityToUse*(dt / numberDivision);
}
for (int i = 0; i < numberDivision; i++)
{
float dtToUse = (dt / numberDivision) + ((dt / numberDivision) * i);
vec3 posToCheck = GetCenter() + velocityToUse*dtToUse;
bool stepUp = false;
if (CheckCollisions(posToCheck, m_previousPosition, &pNormal, &velAmount))
{
// Reset velocity, we don't have any bounce
m_velocity = vec3(0.0f, 0.0f, 0.0f);
velocityToUse = vec3(0.0f, 0.0f, 0.0f);
}
}
// Integrate position
m_position += velocityToUse * dt;
}
// Owning chunks
if (m_pOwningChunk != NULL && m_pOwningChunk->IsSetup() && m_pOwningChunk->IsInsideChunk(m_position))
{
Chunk* pChunk = GetCachedGridChunkOrFromPosition(m_position);
bool active = m_pChunkManager->GetBlockActiveFrom3DPosition(m_position.x, m_position.y, m_position.z, &blockPos, &blockX, &blockY, &blockZ, &pChunk);
if (active == true)
{
// Roll back the integration, since we will intersect the block otherwise
m_position -= m_velocity * dt;
m_velocity = vec3(0.0f, 0.0f, 0.0f);
}
}
else
{
if (m_pOwningChunk != NULL)
{
m_pOwningChunk->RemoveItem(this);
}
m_pOwningChunk = m_pChunkManager->GetChunkFromPosition(m_position.x, m_position.y, m_position.z);
if (m_pOwningChunk != NULL)
{
m_pOwningChunk->AddItem(this);
}
if (m_pOwningChunk == NULL)
{
m_position -= m_velocity * dt;
m_velocity = vec3(0.0f, 0.0f, 0.0f);
}
}
}
else
{
// Integrate position
m_position += m_velocity * dt;
}
m_previousPosition = GetCenter();
}
