// MIT License // Copyright (c) 2019 Erin Catto // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // The above copyright notice and this permission notice shall be included in all // copies or substantial portions of the Software. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. #include "settings.h" #include "test.h" // A motor driven slider crank with joint friction. class SliderCrank2 : public Test { public: SliderCrank2() { b2Body* ground = NULL; { b2BodyDef bd; ground = m_world->CreateBody(&bd); b2EdgeShape shape; shape.SetTwoSided(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(int key) override { switch (key) { case GLFW_KEY_F: m_joint2->EnableMotor(!m_joint2->IsMotorEnabled()); m_joint2->GetBodyB()->SetAwake(true); break; case GLFW_KEY_M: m_joint1->EnableMotor(!m_joint1->IsMotorEnabled()); m_joint1->GetBodyB()->SetAwake(true); break; } } void Step(Settings& settings) override { Test::Step(settings); g_debugDraw.DrawString(5, m_textLine, "Keys: (f) toggle friction, (m) toggle motor"); m_textLine += m_textIncrement; float torque = m_joint1->GetMotorTorque(settings.m_hertz); g_debugDraw.DrawString(5, m_textLine, "Motor Torque = %5.0f", (float) torque); m_textLine += m_textIncrement; } static Test* Create() { return new SliderCrank2; } b2RevoluteJoint* m_joint1; b2PrismaticJoint* m_joint2; }; static int testIndex = RegisterTest("Examples", "Slider Crank 2", SliderCrank2::Create);