/* * Copyright (c) 2007-2009 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 GEARS_H #define GEARS_H class Gears : public Test { public: Gears() { b2Body* ground = NULL; { b2BodyDef bd; ground = m_world->CreateBody(&bd); b2EdgeShape shape; shape.Set(b2Vec2(50.0f, 0.0f), b2Vec2(-50.0f, 0.0f)); ground->CreateFixture(&shape, 0.0f); } // Gears co { b2CircleShape circle1; circle1.m_radius = 1.0f; b2PolygonShape box; box.SetAsBox(0.5f, 5.0f); b2CircleShape circle2; circle2.m_radius = 2.0f; b2BodyDef bd1; bd1.type = b2_staticBody; bd1.position.Set(10.0f, 9.0f); b2Body* body1 = m_world->CreateBody(&bd1); body1->CreateFixture(&circle1, 0.0f); b2BodyDef bd2; bd2.type = b2_dynamicBody; bd2.position.Set(10.0f, 8.0f); b2Body* body2 = m_world->CreateBody(&bd2); body2->CreateFixture(&box, 5.0f); b2BodyDef bd3; bd3.type = b2_dynamicBody; bd3.position.Set(10.0f, 6.0f); b2Body* body3 = m_world->CreateBody(&bd3); body3->CreateFixture(&circle2, 5.0f); b2RevoluteJointDef jd1; jd1.Initialize(body2, body1, bd1.position); b2Joint* joint1 = m_world->CreateJoint(&jd1); b2RevoluteJointDef jd2; jd2.Initialize(body2, body3, bd3.position); b2Joint* joint2 = m_world->CreateJoint(&jd2); b2GearJointDef jd4; jd4.bodyA = body1; jd4.bodyB = body3; jd4.joint1 = joint1; jd4.joint2 = joint2; jd4.ratio = circle2.m_radius / circle1.m_radius; m_world->CreateJoint(&jd4); } { b2CircleShape circle1; circle1.m_radius = 1.0f; b2CircleShape circle2; circle2.m_radius = 2.0f; b2PolygonShape box; box.SetAsBox(0.5f, 5.0f); b2BodyDef bd1; bd1.type = b2_dynamicBody; bd1.position.Set(-3.0f, 12.0f); b2Body* body1 = m_world->CreateBody(&bd1); body1->CreateFixture(&circle1, 5.0f); b2RevoluteJointDef jd1; jd1.bodyA = ground; jd1.bodyB = body1; jd1.localAnchorA = ground->GetLocalPoint(bd1.position); jd1.localAnchorB = body1->GetLocalPoint(bd1.position); jd1.referenceAngle = body1->GetAngle() - ground->GetAngle(); m_joint1 = (b2RevoluteJoint*)m_world->CreateJoint(&jd1); b2BodyDef bd2; bd2.type = b2_dynamicBody; bd2.position.Set(0.0f, 12.0f); b2Body* body2 = m_world->CreateBody(&bd2); body2->CreateFixture(&circle2, 5.0f); b2RevoluteJointDef jd2; jd2.Initialize(ground, body2, bd2.position); m_joint2 = (b2RevoluteJoint*)m_world->CreateJoint(&jd2); b2BodyDef bd3; bd3.type = b2_dynamicBody; bd3.position.Set(2.5f, 12.0f); b2Body* body3 = m_world->CreateBody(&bd3); body3->CreateFixture(&box, 5.0f); b2PrismaticJointDef jd3; jd3.Initialize(ground, body3, bd3.position, b2Vec2(0.0f, 1.0f)); jd3.lowerTranslation = -5.0f; jd3.upperTranslation = 5.0f; jd3.enableLimit = true; m_joint3 = (b2PrismaticJoint*)m_world->CreateJoint(&jd3); b2GearJointDef jd4; jd4.bodyA = body1; jd4.bodyB = body2; jd4.joint1 = m_joint1; jd4.joint2 = m_joint2; jd4.ratio = circle2.m_radius / circle1.m_radius; m_joint4 = (b2GearJoint*)m_world->CreateJoint(&jd4); b2GearJointDef jd5; jd5.bodyA = body2; jd5.bodyB = body3; jd5.joint1 = m_joint2; jd5.joint2 = m_joint3; jd5.ratio = -1.0f / circle2.m_radius; m_joint5 = (b2GearJoint*)m_world->CreateJoint(&jd5); } } void Keyboard(unsigned char key) { switch (key) { case 0: break; } } void Step(Settings* settings) { Test::Step(settings); float32 ratio, value; ratio = m_joint4->GetRatio(); value = m_joint1->GetJointAngle() + ratio * m_joint2->GetJointAngle(); m_debugDraw.DrawString(5, m_textLine, "theta1 + %4.2f * theta2 = %4.2f", (float) ratio, (float) value); m_textLine += 15; ratio = m_joint5->GetRatio(); value = m_joint2->GetJointAngle() + ratio * m_joint3->GetJointTranslation(); m_debugDraw.DrawString(5, m_textLine, "theta2 + %4.2f * delta = %4.2f", (float) ratio, (float) value); m_textLine += 15; } static Test* Create() { return new Gears; } b2RevoluteJoint* m_joint1; b2RevoluteJoint* m_joint2; b2PrismaticJoint* m_joint3; b2GearJoint* m_joint4; b2GearJoint* m_joint5; }; #endif