/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* 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.
*/
#ifndef CAR_H
#define CAR_H
// This is a fun demo that shows off the wheel joint
class Car : public Test
{
public:
Car()
{
m_hz = 4.0f;
m_zeta = 0.7f;
m_speed = 50.0f;
b2Body* ground = NULL;
{
b2BodyDef bd;
ground = m_world->CreateBody(&bd);
b2EdgeShape shape;
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 0.0f;
fd.friction = 0.6f;
shape.Set(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));
ground->CreateFixture(&fd);
float32 hs[10] = {0.25f, 1.0f, 4.0f, 0.0f, 0.0f, -1.0f, -2.0f, -2.0f, -1.25f, 0.0f};
float32 x = 20.0f, y1 = 0.0f, dx = 5.0f;
for (int32 i = 0; i < 10; ++i)
{
float32 y2 = hs[i];
shape.Set(b2Vec2(x, y1), b2Vec2(x + dx, y2));
ground->CreateFixture(&fd);
y1 = y2;
x += dx;
}
for (int32 i = 0; i < 10; ++i)
{
float32 y2 = hs[i];
shape.Set(b2Vec2(x, y1), b2Vec2(x + dx, y2));
ground->CreateFixture(&fd);
y1 = y2;
x += dx;
}
shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
ground->CreateFixture(&fd);
x += 80.0f;
shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
ground->CreateFixture(&fd);
x += 40.0f;
shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 10.0f, 5.0f));
ground->CreateFixture(&fd);
x += 20.0f;
shape.Set(b2Vec2(x, 0.0f), b2Vec2(x + 40.0f, 0.0f));
ground->CreateFixture(&fd);
x += 40.0f;
shape.Set(b2Vec2(x, 0.0f), b2Vec2(x, 20.0f));
ground->CreateFixture(&fd);
}
// Teeter
{
b2BodyDef bd;
bd.position.Set(140.0f, 1.0f);
bd.type = b2_dynamicBody;
b2Body* body = m_world->CreateBody(&bd);
b2PolygonShape box;
box.SetAsBox(10.0f, 0.25f);
body->CreateFixture(&box, 1.0f);
b2RevoluteJointDef jd;
jd.Initialize(ground, body, body->GetPosition());
jd.lowerAngle = -8.0f * b2_pi / 180.0f;
jd.upperAngle = 8.0f * b2_pi / 180.0f;
jd.enableLimit = true;
m_world->CreateJoint(&jd);
body->ApplyAngularImpulse(100.0f);
}
// Bridge
{
int32 N = 20;
b2PolygonShape shape;
shape.SetAsBox(1.0f, 0.125f);
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 1.0f;
fd.friction = 0.6f;
b2RevoluteJointDef jd;
b2Body* prevBody = ground;
for (int32 i = 0; i < N; ++i)
{
b2BodyDef bd;
bd.type = b2_dynamicBody;
bd.position.Set(161.0f + 2.0f * i, -0.125f);
b2Body* body = m_world->CreateBody(&bd);
body->CreateFixture(&fd);
b2Vec2 anchor(160.0f + 2.0f * i, -0.125f);
jd.Initialize(prevBody, body, anchor);
m_world->CreateJoint(&jd);
prevBody = body;
}
b2Vec2 anchor(160.0f + 2.0f * N, -0.125f);
jd.Initialize(prevBody, ground, anchor);
m_world->CreateJoint(&jd);
}
// Boxes
{
b2PolygonShape box;
box.SetAsBox(0.5f, 0.5f);
b2Body* body = NULL;
b2BodyDef bd;
bd.type = b2_dynamicBody;
bd.position.Set(230.0f, 0.5f);
body = m_world->CreateBody(&bd);
body->CreateFixture(&box, 0.5f);
bd.position.Set(230.0f, 1.5f);
body = m_world->CreateBody(&bd);
body->CreateFixture(&box, 0.5f);
bd.position.Set(230.0f, 2.5f);
body = m_world->CreateBody(&bd);
body->CreateFixture(&box, 0.5f);
bd.position.Set(230.0f, 3.5f);
body = m_world->CreateBody(&bd);
body->CreateFixture(&box, 0.5f);
bd.position.Set(230.0f, 4.5f);
body = m_world->CreateBody(&bd);
body->CreateFixture(&box, 0.5f);
}
// Car
{
b2PolygonShape chassis;
b2Vec2 vertices[8];
vertices[0].Set(-1.5f, -0.5f);
vertices[1].Set(1.5f, -0.5f);
vertices[2].Set(1.5f, 0.0f);
vertices[3].Set(0.0f, 0.9f);
vertices[4].Set(-1.15f, 0.9f);
vertices[5].Set(-1.5f, 0.2f);
chassis.Set(vertices, 6);
b2CircleShape circle;
circle.m_radius = 0.4f;
b2BodyDef bd;
bd.type = b2_dynamicBody;
bd.position.Set(0.0f, 1.0f);
m_car = m_world->CreateBody(&bd);
m_car->CreateFixture(&chassis, 1.0f);
b2FixtureDef fd;
fd.shape = &circle;
fd.density = 1.0f;
fd.friction = 0.9f;
bd.position.Set(-1.0f, 0.35f);
m_wheel1 = m_world->CreateBody(&bd);
m_wheel1->CreateFixture(&fd);
bd.position.Set(1.0f, 0.4f);
m_wheel2 = m_world->CreateBody(&bd);
m_wheel2->CreateFixture(&fd);
b2WheelJointDef jd;
b2Vec2 axis(0.0f, 1.0f);
jd.Initialize(m_car, m_wheel1, m_wheel1->GetPosition(), axis);
jd.motorSpeed = 0.0f;
jd.maxMotorTorque = 20.0f;
jd.enableMotor = true;
jd.frequencyHz = m_hz;
jd.dampingRatio = m_zeta;
m_spring1 = (b2WheelJoint*)m_world->CreateJoint(&jd);
jd.Initialize(m_car, m_wheel2, m_wheel2->GetPosition(), axis);
jd.motorSpeed = 0.0f;
jd.maxMotorTorque = 10.0f;
jd.enableMotor = false;
jd.frequencyHz = m_hz;
jd.dampingRatio = m_zeta;
m_spring2 = (b2WheelJoint*)m_world->CreateJoint(&jd);
}
}
void Keyboard(unsigned char key)
{
switch (key)
{
case 'a':
m_spring1->SetMotorSpeed(m_speed);
break;
case 's':
m_spring1->SetMotorSpeed(0.0f);
break;
case 'd':
m_spring1->SetMotorSpeed(-m_speed);
break;
case 'q':
m_hz = b2Max(0.0f, m_hz - 1.0f);
m_spring1->SetSpringFrequencyHz(m_hz);
m_spring2->SetSpringFrequencyHz(m_hz);
break;
case 'e':
m_hz += 1.0f;
m_spring1->SetSpringFrequencyHz(m_hz);
m_spring2->SetSpringFrequencyHz(m_hz);
break;
}
}
void Step(Settings* settings)
{
m_debugDraw.DrawString(5, m_textLine, "Keys: left = a, brake = s, right = d, hz down = q, hz up = e");
m_textLine += 15;
m_debugDraw.DrawString(5, m_textLine, "frequency = %g hz, damping ratio = %g", m_hz, m_zeta);
m_textLine += 15;
settings->viewCenter.x = m_car->GetPosition().x;
Test::Step(settings);
}
static Test* Create()
{
return new Car;
}
b2Body* m_car;
b2Body* m_wheel1;
b2Body* m_wheel2;
float32 m_hz;
float32 m_zeta;
float32 m_speed;
b2WheelJoint* m_spring1;
b2WheelJoint* m_spring2;
};
#endif