love/src/modules/physics/box2d/Body.cpp

/**
 * Copyright (c) 2006-2020 LOVE Development Team
 *
 * 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 "Body.h"

#include "common/math.h"

#include "Shape.h"
#include "Fixture.h"
#include "World.h"
#include "Physics.h"

// Needed for luax_pushjoint.
#include "wrap_Joint.h"

namespace love
{
namespace physics
{
namespace box2d
{

Body::Body(World *world, b2Vec2 p, Body::Type type)
	: world(world)
	, udata(nullptr)
{
	udata = new bodyudata();
	udata->ref = nullptr;
	b2BodyDef def;
	def.position = Physics::scaleDown(p);
	def.userData.pointer = (uintptr_t)udata;
	body = world->world->CreateBody(&def);
	// Box2D body holds a reference to the love Body.
	this->retain();
	this->setType(type);
	world->registerObject(body, this);
}

Body::~Body()
{
	if (!udata)
		return;

	if (udata->ref)
		delete udata->ref;

	delete udata;
}

float Body::getX()
{
	return Physics::scaleUp(body->GetPosition().x);
}

float Body::getY()
{
	return Physics::scaleUp(body->GetPosition().y);
}

void Body::getPosition(float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetPosition());
	x_o = v.x;
	y_o = v.y;
}

void Body::getLinearVelocity(float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLinearVelocity());
	x_o = v.x;
	y_o = v.y;
}

float Body::getAngle()
{
	return body->GetAngle();
}

void Body::getWorldCenter(float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetWorldCenter());
	x_o = v.x;
	y_o = v.y;
}

void Body::getLocalCenter(float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLocalCenter());
	x_o = v.x;
	y_o = v.y;
}

float Body::getAngularVelocity() const
{
	return body->GetAngularVelocity();
}

void Body::getKinematicState(b2Vec2 &pos_o, float &a_o, b2Vec2 &vel_o, float &da_o) const
{
	pos_o = Physics::scaleUp(body->GetPosition());
	a_o = body->GetAngle();
	vel_o = Physics::scaleUp(body->GetLinearVelocity());
	da_o = body->GetAngularVelocity();
}

float Body::getMass() const
{
	return body->GetMass();
}

float Body::getInertia() const
{
	return Physics::scaleUp(Physics::scaleUp(body->GetInertia()));
}

int Body::getMassData(lua_State *L)
{
	b2MassData data;
	body->GetMassData(&data);
	b2Vec2 center = Physics::scaleUp(data.center);
	lua_pushnumber(L, center.x);
	lua_pushnumber(L, center.y);
	lua_pushnumber(L, data.mass);
	lua_pushnumber(L, Physics::scaleUp(Physics::scaleUp(data.I)));
	return 4;
}

float Body::getAngularDamping() const
{
	return body->GetAngularDamping();
}

float Body::getLinearDamping() const
{
	return body->GetLinearDamping();
}

float Body::getGravityScale() const
{
	return body->GetGravityScale();
}

Body::Type Body::getType() const
{
	switch (body->GetType())
	{
	case b2_staticBody:
		return BODY_STATIC;
		break;
	case b2_dynamicBody:
		return BODY_DYNAMIC;
		break;
	case b2_kinematicBody:
		return BODY_KINEMATIC;
		break;
	default:
		return BODY_INVALID;
		break;
	}
}

void Body::applyLinearImpulse(float jx, float jy, bool wake)
{
	body->ApplyLinearImpulse(Physics::scaleDown(b2Vec2(jx, jy)), body->GetWorldCenter(), wake);
}

void Body::applyLinearImpulse(float jx, float jy, float rx, float ry, bool wake)
{
	body->ApplyLinearImpulse(Physics::scaleDown(b2Vec2(jx, jy)), Physics::scaleDown(b2Vec2(rx, ry)), wake);
}

void Body::applyAngularImpulse(float impulse, bool wake)
{
	// Angular impulse is in kg*m^2/s, meaning it needs to be scaled twice
	body->ApplyAngularImpulse(Physics::scaleDown(Physics::scaleDown(impulse)), wake);
}

void Body::applyTorque(float t, bool wake)
{
	// Torque is in N*m, or kg*m^2/s^2, meaning it also needs to be scaled twice
	body->ApplyTorque(Physics::scaleDown(Physics::scaleDown(t)), wake);
}

void Body::applyForce(float fx, float fy, float rx, float ry, bool wake)
{
	body->ApplyForce(Physics::scaleDown(b2Vec2(fx, fy)), Physics::scaleDown(b2Vec2(rx, ry)), wake);
}

void Body::applyForce(float fx, float fy, bool wake)
{
	body->ApplyForceToCenter(Physics::scaleDown(b2Vec2(fx, fy)), wake);
}

void Body::setX(float x)
{
	body->SetTransform(Physics::scaleDown(b2Vec2(x, getY())), getAngle());
}

void Body::setY(float y)
{
	body->SetTransform(Physics::scaleDown(b2Vec2(getX(), y)), getAngle());
}

void Body::setLinearVelocity(float x, float y)
{
	body->SetLinearVelocity(Physics::scaleDown(b2Vec2(x, y)));
}

void Body::setAngle(float d)
{
	body->SetTransform(body->GetPosition(), d);
}

void Body::setAngularVelocity(float r)
{
	body->SetAngularVelocity(r);
}

void Body::setKinematicState(b2Vec2 pos, float a, b2Vec2 vel, float da)
{
	body->SetTransform(Physics::scaleDown(pos), a);
	body->SetLinearVelocity(Physics::scaleDown(vel));
	body->SetAngularVelocity(da);
}

void Body::setPosition(float x, float y)
{
	body->SetTransform(Physics::scaleDown(b2Vec2(x, y)), body->GetAngle());
}

void Body::setAngularDamping(float d)
{
	body->SetAngularDamping(d);
}

void Body::setLinearDamping(float d)
{
	body->SetLinearDamping(d);
}

void Body::resetMassData()
{
	body->ResetMassData();
}

void Body::setMassData(float x, float y, float m, float i)
{
	b2MassData massData;
	massData.center = Physics::scaleDown(b2Vec2(x, y));
	massData.mass = m;
	massData.I = Physics::scaleDown(Physics::scaleDown(i));
	body->SetMassData(&massData);
}

void Body::setMass(float m)
{
	b2MassData data;
	body->GetMassData(&data);
	data.mass = m;
	body->SetMassData(&data);
}

void Body::setInertia(float i)
{
	b2MassData massData;
	massData.center = body->GetLocalCenter();
	massData.mass = body->GetMass();
	massData.I = Physics::scaleDown(Physics::scaleDown(i));
	body->SetMassData(&massData);
}

void Body::setGravityScale(float scale)
{
	body->SetGravityScale(scale);
}

void Body::setType(Body::Type type)
{
	switch (type)
	{
	case Body::BODY_STATIC:
		body->SetType(b2_staticBody);
		break;
	case Body::BODY_DYNAMIC:
		body->SetType(b2_dynamicBody);
		break;
	case Body::BODY_KINEMATIC:
		body->SetType(b2_kinematicBody);
		break;
	default:
		break;
	}
}

void Body::getWorldPoint(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetWorldPoint(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

void Body::getWorldVector(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetWorldVector(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

int Body::getWorldPoints(lua_State *L)
{
	int argc = lua_gettop(L);
	int vcount = (int)argc/2;
	// at least one point
	love::luax_assert_argc(L, 2);

	for (int i = 0; i<vcount; i++)
	{
		float x = (float)lua_tonumber(L, 1);
		float y = (float)lua_tonumber(L, 2);
		// Remove them, so we don't run out of stack space
		lua_remove(L, 1);
		lua_remove(L, 1);
		// Time for scaling
		b2Vec2 point = Physics::scaleUp(body->GetWorldPoint(Physics::scaleDown(b2Vec2(x, y))));
		// And then we push the result
		lua_pushnumber(L, point.x);
		lua_pushnumber(L, point.y);
	}

	return argc;
}

void Body::getLocalPoint(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLocalPoint(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

void Body::getLocalVector(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLocalVector(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

int Body::getLocalPoints(lua_State *L)
{
	int argc = lua_gettop(L);
	int vcount = (int)argc/2;
	// at least one point
	love::luax_assert_argc(L, 2);

	for (int i = 0; i<vcount; i++)
	{
		float x = (float)lua_tonumber(L, 1);
		float y = (float)lua_tonumber(L, 2);
		// Remove them, so we don't run out of stack space
		lua_remove(L, 1);
		lua_remove(L, 1);
		// Time for scaling
		b2Vec2 point = Physics::scaleUp(body->GetLocalPoint(Physics::scaleDown(b2Vec2(x, y))));
		// And then we push the result
		lua_pushnumber(L, point.x);
		lua_pushnumber(L, point.y);
	}

	return argc;
}

void Body::getLinearVelocityFromWorldPoint(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLinearVelocityFromWorldPoint(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

void Body::getLinearVelocityFromLocalPoint(float x, float y, float &x_o, float &y_o)
{
	b2Vec2 v = Physics::scaleUp(body->GetLinearVelocityFromLocalPoint(Physics::scaleDown(b2Vec2(x, y))));
	x_o = v.x;
	y_o = v.y;
}

bool Body::isBullet() const
{
	return body->IsBullet();
}

void Body::setBullet(bool bullet)
{
	return body->SetBullet(bullet);
}

bool Body::isEnabled() const
{
	return body->IsEnabled();
}

bool Body::isAwake() const
{
	return body->IsAwake();
}

void Body::setSleepingAllowed(bool allow)
{
	body->SetSleepingAllowed(allow);
}

bool Body::isSleepingAllowed() const
{
	return body->IsSleepingAllowed();
}

void Body::setEnabled(bool enabled)
{
	body->SetEnabled(enabled);
}

void Body::setAwake(bool awake)
{
	body->SetAwake(awake);
}

void Body::setFixedRotation(bool fixed)
{
	body->SetFixedRotation(fixed);
}

bool Body::isFixedRotation() const
{
	return body->IsFixedRotation();
}

bool Body::isTouching(Body *other) const
{
	const b2ContactEdge *ce = body->GetContactList();
	b2Body *otherbody = other->body;

	while (ce != nullptr)
	{
		if (ce->other == otherbody && ce->contact != nullptr && ce->contact->IsTouching())
			return true;

		ce = ce->next;
	}

	return false;
}

World *Body::getWorld() const
{
	return world;
}

int Body::getFixtures(lua_State *L) const
{
	lua_newtable(L);
	b2Fixture *f = body->GetFixtureList();
	int i = 1;
	do
	{
		if (!f)
			break;
		Fixture *fixture = (Fixture *)world->findObject(f);
		if (!fixture)
			throw love::Exception("A fixture has escaped Memoizer!");
		luax_pushtype(L, fixture);
		lua_rawseti(L, -2, i);
		i++;
	}
	while ((f = f->GetNext()));
	return 1;
}

int Body::getJoints(lua_State *L) const
{
	lua_newtable(L);
	const b2JointEdge *je = body->GetJointList();
	int i = 1;

	do
	{
		if (!je)
			break;

		Joint *joint = (Joint *) world->findObject(je->joint);
		if (!joint)
			throw love::Exception("A joint has escaped Memoizer!");

		luax_pushjoint(L, joint);
		lua_rawseti(L, -2, i);
		i++;
	}
	while ((je = je->next));

	return 1;
}

int Body::getContacts(lua_State *L) const
{
	lua_newtable(L);
	const b2ContactEdge *ce = body->GetContactList();
	int i = 1;
	do
	{
		if (!ce)
			break;

		Contact *contact = (Contact *) world->findObject(ce->contact);
		if (!contact)
			contact = new Contact(world, ce->contact);
		else
			contact->retain();

		luax_pushtype(L, contact);
		contact->release();
		lua_rawseti(L, -2, i);
		i++;
	}
	while ((ce = ce->next));
	return 1;
}

void Body::destroy()
{
	if (world->world->IsLocked())
	{
		// Called during time step. Save reference for destruction afterwards.
		this->retain();
		world->destructBodies.push_back(this);
		return;
	}

	world->world->DestroyBody(body);
	world->unregisterObject(body);
	body = NULL;

	// Remove userdata reference to avoid it sticking around after GC
	if (udata && udata->ref)
		udata->ref->unref();

	// Box2D body destroyed. Release its reference to the love Body.
	this->release();
}

int Body::setUserData(lua_State *L)
{
	love::luax_assert_argc(L, 1, 1);

	if (udata == nullptr)
	{
		udata = new bodyudata();
		body->GetUserData().pointer = (uintptr_t)udata;
	}

	if(!udata->ref)
		udata->ref = new Reference();

	udata->ref->ref(L);

	return 0;
}

int Body::getUserData(lua_State *L)
{
	if (udata != nullptr && udata->ref != nullptr)
		udata->ref->push(L);
	else
		lua_pushnil(L);

	return 1;
}

} // box2d
} // physics
} // love