/* * Copyright (c) 2006-2009 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 SLIDER_CRANK_H #define SLIDER_CRANK_H // A motor driven slider crank with joint friction. class SliderCrank : public Test { public: SliderCrank() { b2Body* ground = NULL; { b2BodyDef bd; ground = m_world->CreateBody(&bd); b2EdgeShape shape; shape.Set(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f)); ground->CreateFixture(&shape, 0.0f); } { b2Body* prevBody = ground; // Define crank. { b2PolygonShape shape; shape.SetAsBox(0.5f, 2.0f); b2BodyDef bd; bd.type = b2_dynamicBody; bd.position.Set(0.0f, 7.0f); b2Body* body = m_world->CreateBody(&bd); body->CreateFixture(&shape, 2.0f); b2RevoluteJointDef rjd; rjd.Initialize(prevBody, body, b2Vec2(0.0f, 5.0f)); rjd.motorSpeed = 1.0f * b2_pi; rjd.maxMotorTorque = 10000.0f; rjd.enableMotor = true; m_joint1 = (b2RevoluteJoint*)m_world->CreateJoint(&rjd); prevBody = body; } // Define follower. { b2PolygonShape shape; shape.SetAsBox(0.5f, 4.0f); b2BodyDef bd; bd.type = b2_dynamicBody; bd.position.Set(0.0f, 13.0f); b2Body* body = m_world->CreateBody(&bd); body->CreateFixture(&shape, 2.0f); b2RevoluteJointDef rjd; rjd.Initialize(prevBody, body, b2Vec2(0.0f, 9.0f)); rjd.enableMotor = false; m_world->CreateJoint(&rjd); prevBody = body; } // Define piston { b2PolygonShape shape; shape.SetAsBox(1.5f, 1.5f); b2BodyDef bd; bd.type = b2_dynamicBody; bd.fixedRotation = true; bd.position.Set(0.0f, 17.0f); b2Body* body = m_world->CreateBody(&bd); body->CreateFixture(&shape, 2.0f); b2RevoluteJointDef rjd; rjd.Initialize(prevBody, body, b2Vec2(0.0f, 17.0f)); m_world->CreateJoint(&rjd); b2PrismaticJointDef pjd; pjd.Initialize(ground, body, b2Vec2(0.0f, 17.0f), b2Vec2(0.0f, 1.0f)); pjd.maxMotorForce = 1000.0f; pjd.enableMotor = true; m_joint2 = (b2PrismaticJoint*)m_world->CreateJoint(&pjd); } // Create a payload { b2PolygonShape shape; shape.SetAsBox(1.5f, 1.5f); b2BodyDef bd; bd.type = b2_dynamicBody; bd.position.Set(0.0f, 23.0f); b2Body* body = m_world->CreateBody(&bd); body->CreateFixture(&shape, 2.0f); } } } void Keyboard(unsigned char key) { switch (key) { case 'f': m_joint2->EnableMotor(!m_joint2->IsMotorEnabled()); m_joint2->GetBodyB()->SetAwake(true); break; case 'm': m_joint1->EnableMotor(!m_joint1->IsMotorEnabled()); m_joint1->GetBodyB()->SetAwake(true); break; } } void Step(Settings* settings) { Test::Step(settings); m_debugDraw.DrawString(5, m_textLine, "Keys: (f) toggle friction, (m) toggle motor"); m_textLine += DRAW_STRING_NEW_LINE; float32 torque = m_joint1->GetMotorTorque(settings->hz); m_debugDraw.DrawString(5, m_textLine, "Motor Torque = %5.0f", (float) torque); m_textLine += DRAW_STRING_NEW_LINE; } static Test* Create() { return new SliderCrank; } b2RevoluteJoint* m_joint1; b2PrismaticJoint* m_joint2; }; #endif