[英]Top-Down Car in JBox2D libGDX movement issues
我試圖基於Emanuele Feronato的“兩種制作Box2D汽車的方法”來實現自上而下的汽車游戲的Java版本。 我知道box2d的一些基礎知識,並且在很大程度上我將代碼轉換為Java,幾乎沒有例外。
但是,當我運行程序時,我的車不會移動。
如果我把所有的輪子都變成一個動態的車身(左前方除外)開始前后移動,前后甩車,但最后卻沒有任何地方。 前兩個關節是旋轉關節,每個關節都有馬達,而后背是棱柱形,所以如果我錯了,請糾正我,但前兩個應該是唯一“旋轉”/移動的。 我覺得我正在做一些可怕的錯誤,但到處都是我看起來總是在行動腳本,所以我不是百分之百肯定是錯的。
我檢查過,所有的車輪都在正確的位置,接頭也被放到了正確的車輪上。 我檢查了電機速度,它也在運行。 “ldirection”和“rdirection”的x分量始終為0,因此它會消除橫向速度,而y始終是一個值。 那真的應該向前邁進嗎?
當車身上下移動時,左前輪始終與車身保持相同的距離。 所以左前線似乎正常運作。 我檢查了所有代碼,以確保右前輪與左輪相同。
開車
當向前加速時,只有兩個右輪和后左輪來回移動。
當我開始轉動兩個前輪后,兩個車輪仍然與汽車保持一致但開始以略微傾斜的方式移動。 最終當前輪轉動90度時,它們開始幾乎旋轉關節的中心。
初始化
this.world = new World(new Vector2(0, 0), false);
this.box2Drender = new Box2DDebugRenderer();
this.LeftPJointDef = new PrismaticJointDef();
this.RightPJointDef = new PrismaticJointDef();
this.RightJointDef = new RevoluteJointDef();
this.LeftJointDef = new RevoluteJointDef();
this.CarBody = new PolygonShape();
this.RightRWheelShape = new PolygonShape();
this.RightFWheelShape = new PolygonShape();
this.LeftRWheelShape = new PolygonShape();
this.LeftFWheelShape = new PolygonShape();
this.LeftRWheelDef = new BodyDef();
this.RightRWheelDef = new BodyDef();
this.RightFWheelDef = new BodyDef();
this.LeftFWheelDef = new BodyDef();
this.bodyD = new BodyDef();
this.CarFixDef = new FixtureDef();
this.x = x;
this.y = y;
this.Cpos = new Vector2(x,y);
this.RRW = new Vector2((this.x + (this.x * XPrc)), (this.y + (this.y * -YPrc)));
this.RLW = new Vector2((this.x + (this.x * -XPrc)), (this.y + (this.y * -YPrc)));
this.FRW = new Vector2((this.x + (this.x * XPrc)), (this.y + (this.y * YPrc)));
this.FLW = new Vector2((this.x + (this.x * -XPrc)), (this.y + (this.y * YPrc)));
this.WheelSizeX = this.width * 0.25f;
this.WheelSizeY = this.length * 0.30f;
//setting bodyDef damping
bodyD.linearDamping = 0.5f;
bodyD.angularDamping = 0.5f;
//Adding bodyDef to the world and setting type as Dynamic
body = world.createBody(bodyD);
body.setType(BodyDef.BodyType.DynamicBody);
//setting the body position in the world using the Vector given.
body.setTransform(this.Cpos, (float) ((Math.PI) / 2));
//Adding the calculated Position vecotrs of the wheel's to each wheel def.
RightFWheelDef.position.add(FRW);
LeftFWheelDef.position.add(FLW);
RightRWheelDef.position.add(RRW);
LeftRWheelDef.position.add(RLW);
//Adding the wheels to the world using the Wheel Defs.
RightFWheel = world.createBody(RightFWheelDef);
LeftFWheel = world.createBody(LeftFWheelDef);
RightRWheel = world.createBody(RightRWheelDef);
LeftRWheel = world.createBody(LeftRWheelDef);
RightFWheel.setType(BodyDef.BodyType.DynamicBody);
RightRWheel.setType(BodyDef.BodyType.DynamicBody);
LeftFWheel.setType(BodyDef.BodyType.DynamicBody);
LeftRWheel.setType(BodyDef.BodyType.DynamicBody);
//Setting the car(box) and wheel size
CarBody.setAsBox(this.length, this.width);
LeftFWheelShape.setAsBox(WheelSizeX, WheelSizeY);
LeftRWheelShape.setAsBox(WheelSizeX, WheelSizeY);
RightRWheelShape.setAsBox(WheelSizeX, WheelSizeY);
RightFWheelShape.setAsBox(WheelSizeX, WheelSizeY);
CarFixDef.shape = CarBody;
RightFWheel.createFixture(RightFWheelShape, 1);
RightRWheel.createFixture(RightRWheelShape, 1);
LeftFWheel.createFixture(LeftFWheelShape, 1);
LeftRWheel.createFixture(LeftRWheelShape, 1);
body.createFixture(CarFixDef);
LeftJointDef.enableMotor = true;
RightJointDef.enableMotor = true;
LeftJointDef.maxMotorTorque = 500;
RightJointDef.maxMotorTorque = 500;
//Setting Front Wheel joints in respects to the wheels and body
LeftJointDef.initialize(body, LeftFWheel, LeftFWheel.getWorldCenter());
RightJointDef.initialize(body, RightFWheel, RightFWheel.getWorldCenter());
this.LeftJoint = (RevoluteJoint) world.createJoint(LeftJointDef);
this.RightJoint = (RevoluteJoint) world.createJoint(RightJointDef);
LeftPJointDef.enableLimit = true;
RightPJointDef.enableLimit = true;
//Translation Limit
LeftPJointDef.lowerTranslation = 0;
LeftPJointDef.upperTranslation = 0;
RightPJointDef.lowerTranslation = 0;
RightPJointDef.upperTranslation = 0;
//Setting Rear wheel joints in respects to wheel and body
LeftPJointDef.initialize(body, LeftRWheel, LeftRWheel.getWorldCenter(), new Vector2(1, 0));
RightPJointDef.initialize(body, RightRWheel, RightRWheel.getWorldCenter(), new Vector2(1, 0));
//adding the P Joints to the world.
this.LeftPJoint = (PrismaticJoint) world.createJoint(LeftPJointDef);
this.RightPJoint = (PrismaticJoint) world.createJoint(RightPJointDef);
這是我的更新方法。
KillOrthoVelocity(LeftFWheel);
KillOrthoVelocity(RightFWheel);
KillOrthoVelocity(LeftRWheel);
KillOrthoVelocity(RightRWheel);
//Driving
float r1 = LeftFWheel.getTransform().getRotation();
Vector2 ldirection = new Vector2((float) -Math.sin(r1), (float) Math.cos(r1));
ldirection.scl(enginespeed);
float r2 = RightFWheel.getTransform().getRotation();
Vector2 rdirection = new Vector2((float) -Math.sin(r2), (float) Math.cos(r2));
rdirection.scl(enginespeed);
LeftFWheel.applyForce(ldirection, LeftFWheel.getPosition(), true);
RightFWheel.applyForce(rdirection, RightFWheel.getPosition(), true);
//Steering
float movespeed;
movespeed = steerAng - LeftJoint.getJointAngle();
LeftJoint.setMotorSpeed(movespeed * AngleSpeed);
movespeed = steerAng - RightJoint.getJointAngle();
RightJoint.setMotorSpeed(movespeed * AngleSpeed);
world.step(dt, 6, 2);
KillOrthoVelocity類似於獲得“ldirection”
Vector2 localP = new Vector2(0, 0);
Vector2 velocity = body.getLinearVelocityFromLocalPoint(localP);
float r = body.getTransform().getRotation();
Vector2 sideways = new Vector2((float) -Math.sin(r), (float) Math.cos(r));
sideways.scl(velocity.dot(sideways));
body.setLinearVelocity(sideways);
任何建議將非常感謝! 即使只是一個線索將是非常有幫助的! 謝謝!
try this code
RaceCar::RaceCar( b2World* world )
{
b2Vec2 race_car_pos( 13.0f,
13.0f );
/ Create race car chassis
{
// Physics Body Shape
b2Vec2 verticies[8];
verticies[0].Set( 1.5f, 0.0f );
verticies[1].Set( 3.0f, 2.5f );
verticies[2].Set( 2.8f, 5.5f );
verticies[3].Set( 1.0f, 10.0f );
verticies[4].Set( -1.0f,
10.0f );
verticies[5].Set( -2.8f, 5.5f );
verticies[6].Set( -3.0f, 2.5f );
verticies[7].Set( -1.5f, 0.0f );
b2PolygonShape body_shape;
body_shape.Set( verticies, 8 );
// Physics body definition
b2BodyDef body_def;
body_def.type
= b2_dynamicBody;
// body_def.position =b2Vec2(3,3);
// Physics Body Fixture
b2FixtureDef body_fixture;
body_fixture.shape = &body_shape;
body_fixture.density = 0.1f;
m_chassisPhysicsBody = world->CreateBody( &body_def );
m_chassisPhysicsBody->CreateFixture( &body_fixture ); m_chassisPhysicsBody->SetUserData( this );
m_chassisPhysicsBody->SetTransform( race_car_pos, 0.0f );
}
// Tires
{ b2Vec2 pos = m_chassisPhysicsBody->GetPosition();
// Top left tire
{
RCTire* tire_top_left = new RCTire( world );
tire_top_left->setPosition( race_car_pos );
m_tires.push_back( tire_top_left );
b2RevoluteJointDef joint_def;
joint_def.enableLimit = true;
joint_def.lowerAngle = 0.0f;
joint_def.upperAngle = 0.0f;
joint_def.bodyA = m_chassisPhysicsBody;
joint_def.localAnchorB.SetZero();
joint_def.bodyB = tire_top_left->getPhysicsBody();
joint_def.localAnchorA.Set( -3.0f, 8.5f );
b2RevoluteJoint* joint = static_cast<b2RevoluteJoint*>( world->CreateJoint( &joint_def ) );
tire_top_left->setJointToChassis( joint ); }
// Top right tire
{
RCTire* tire_top_right = new RCTire( world );
tire_top_right->setPosition( race_car_pos );
m_tires.push_back( tire_top_right );
b2RevoluteJointDef joint_def;
joint_def.enableLimit = true;
joint_def.lowerAngle = 0.0f;
joint_def.upperAngle = 0.0f;
joint_def.bodyA = m_chassisPhysicsBody;
joint_def.localAnchorB.SetZero();
joint_def.bodyB = tire_top_right->getPhysicsBody();
joint_def.localAnchorA.Set( 3.0f, 8.5f );
b2RevoluteJoint* joint = static_cast<b2RevoluteJoint*>( world->CreateJoint( &joint_def ) );
tire_top_right->setJointToChassis( joint ); }
// Bottom left tire
{
RCTire* tire_bottom_left = new RCTire( world );
tire_bottom_left->setPosition( race_car_pos );
m_tires.push_back( tire_bottom_left );
b2RevoluteJointDef joint_def;
joint_def.enableLimit = true;
joint_def.lowerAngle = 0.0f;
joint_def.upperAngle = 0.0f;
joint_def.bodyA = m_chassisPhysicsBody;
joint_def.localAnchorB.SetZero();
joint_def.bodyB = tire_bottom_left->getPhysicsBody();
joint_def.localAnchorA.Set( -3.0f, 0.5f );
b2RevoluteJoint* joint = static_cast<b2RevoluteJoint*>( world->CreateJoint( &joint_def ) );
tire_bottom_left->setJointToChassis( joint ); }
// Bottom right tire {
RCTire* tire_bottom_right = new RCTire( world );
tire_bottom_right->setPosition( race_car_pos );
m_tires.push_back( tire_bottom_right );
b2RevoluteJointDef joint_def;
joint_def.enableLimit = true;
joint_def.lowerAngle = 0.0f;
joint_def.upperAngle = 0.0f;
joint_def.bodyA = m_chassisPhysicsBody;
joint_def.localAnchorB.SetZero();
joint_def.bodyB = tire_bottom_right->getPhysicsBody();
joint_def.localAnchorA.Set( 3.0f, 0.5f );
world->CreateJoint( &joint_def );
b2RevoluteJoint* joint = static_cast<b2RevoluteJoint*>( world->CreateJoint( &joint_def ) );
tire_bottom_right->setJointToChassis( joint ); } } }
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