71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
/*
|
|
* Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
|
|
*
|
|
* This software is provided 'as-is', without any express or implied
|
|
* warranty. In no event will the authors be held liable for any damages
|
|
* arising from the use of this software.
|
|
* Permission is granted to anyone to use this software for any purpose,
|
|
* including commercial applications, and to alter it and redistribute it
|
|
* freely, subject to the following restrictions:
|
|
* 1. The origin of this software must not be misrepresented; you must not
|
|
* claim that you wrote the original software. If you use this software
|
|
* in a product, an acknowledgment in the product documentation would be
|
|
* appreciated but is not required.
|
|
* 2. Altered source versions must be plainly marked as such, and must not be
|
|
* misrepresented as being the original software.
|
|
* 3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
|
|
#include "b2GravityController.h"
|
|
|
|
b2GravityController::b2GravityController(const b2GravityControllerDef* def) : b2Controller(def)
|
|
{
|
|
G = def->G;
|
|
invSqr = def->invSqr;
|
|
}
|
|
|
|
void b2GravityController::Step(const b2TimeStep& step)
|
|
{
|
|
B2_NOT_USED(step);
|
|
if(invSqr){
|
|
for(b2ControllerEdge *i=m_bodyList;i;i=i->nextBody){
|
|
b2Body* body1 = i->body;
|
|
for(b2ControllerEdge *j=m_bodyList;j!=i;j=j->nextBody){
|
|
b2Body* body2 = j->body;
|
|
b2Vec2 d = body2->GetWorldCenter() - body1->GetWorldCenter();
|
|
float32 r2 = d.LengthSquared();
|
|
if(r2 < B2_FLT_EPSILON)
|
|
continue;
|
|
b2Vec2 f = G / r2 / sqrt(r2) * body1->GetMass() * body2->GetMass() * d;
|
|
body1->ApplyForce(f , body1->GetWorldCenter());
|
|
body2->ApplyForce(-1.0f*f, body2->GetWorldCenter());
|
|
}
|
|
}
|
|
}else{
|
|
for(b2ControllerEdge *i=m_bodyList;i;i=i->nextBody){
|
|
b2Body* body1 = i->body;
|
|
for(b2ControllerEdge *j=m_bodyList;j!=i;j=j->nextBody){
|
|
b2Body* body2 = j->body;
|
|
b2Vec2 d = body2->GetWorldCenter() - body1->GetWorldCenter();
|
|
float32 r2 = d.LengthSquared();
|
|
if(r2 < B2_FLT_EPSILON)
|
|
continue;
|
|
b2Vec2 f = G / r2 * body1->GetMass() * body2->GetMass() * d;
|
|
body1->ApplyForce(f , body1->GetWorldCenter());
|
|
body2->ApplyForce(-1.0f*f, body2->GetWorldCenter());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void b2GravityController::Destroy(b2BlockAllocator* allocator)
|
|
{
|
|
allocator->Free(this, sizeof(b2GravityController));
|
|
}
|
|
|
|
b2GravityController* b2GravityControllerDef::Create(b2BlockAllocator* allocator) const
|
|
{
|
|
void* mem = allocator->Allocate(sizeof(b2GravityController));
|
|
return new (mem) b2GravityController(this);
|
|
}
|