1 /* 2 * Copyright (c) 2007-2009 Erin Catto http://www.box2d.org 3 * 4 * This software is provided 'as-is', without any express or implied 5 * warranty. In no event will the authors be held liable for any damages 6 * arising from the use of this software. 7 * Permission is granted to anyone to use this software for any purpose, 8 * including commercial applications, and to alter it and redistribute it 9 * freely, subject to the following restrictions: 10 * 1. The origin of this software must not be misrepresented; you must not 11 * claim that you wrote the original software. If you use this software 12 * in a product, an acknowledgment in the product documentation would be 13 * appreciated but is not required. 14 * 2. Altered source versions must be plainly marked as such, and must not be 15 * misrepresented as being the original software. 16 * 3. This notice may not be removed or altered from any source distribution. 17 */ 18 19 #ifndef GEARS_H 20 #define GEARS_H 21 22 class Gears : public Test 23 { 24 public: Gears()25 Gears() 26 { 27 b2Body* ground = NULL; 28 { 29 b2BodyDef bd; 30 ground = m_world->CreateBody(&bd); 31 32 b2EdgeShape shape; 33 shape.Set(b2Vec2(50.0f, 0.0f), b2Vec2(-50.0f, 0.0f)); 34 ground->CreateFixture(&shape, 0.0f); 35 } 36 37 // Gears co 38 { 39 b2CircleShape circle1; 40 circle1.m_radius = 1.0f; 41 42 b2PolygonShape box; 43 box.SetAsBox(0.5f, 5.0f); 44 45 b2CircleShape circle2; 46 circle2.m_radius = 2.0f; 47 48 b2BodyDef bd1; 49 bd1.type = b2_staticBody; 50 bd1.position.Set(10.0f, 9.0f); 51 b2Body* body1 = m_world->CreateBody(&bd1); 52 body1->CreateFixture(&circle1, 0.0f); 53 54 b2BodyDef bd2; 55 bd2.type = b2_dynamicBody; 56 bd2.position.Set(10.0f, 8.0f); 57 b2Body* body2 = m_world->CreateBody(&bd2); 58 body2->CreateFixture(&box, 5.0f); 59 60 b2BodyDef bd3; 61 bd3.type = b2_dynamicBody; 62 bd3.position.Set(10.0f, 6.0f); 63 b2Body* body3 = m_world->CreateBody(&bd3); 64 body3->CreateFixture(&circle2, 5.0f); 65 66 b2RevoluteJointDef jd1; 67 jd1.Initialize(body2, body1, bd1.position); 68 b2Joint* joint1 = m_world->CreateJoint(&jd1); 69 70 b2RevoluteJointDef jd2; 71 jd2.Initialize(body2, body3, bd3.position); 72 b2Joint* joint2 = m_world->CreateJoint(&jd2); 73 74 b2GearJointDef jd4; 75 jd4.bodyA = body1; 76 jd4.bodyB = body3; 77 jd4.joint1 = joint1; 78 jd4.joint2 = joint2; 79 jd4.ratio = circle2.m_radius / circle1.m_radius; 80 m_world->CreateJoint(&jd4); 81 } 82 83 { 84 b2CircleShape circle1; 85 circle1.m_radius = 1.0f; 86 87 b2CircleShape circle2; 88 circle2.m_radius = 2.0f; 89 90 b2PolygonShape box; 91 box.SetAsBox(0.5f, 5.0f); 92 93 b2BodyDef bd1; 94 bd1.type = b2_dynamicBody; 95 bd1.position.Set(-3.0f, 12.0f); 96 b2Body* body1 = m_world->CreateBody(&bd1); 97 body1->CreateFixture(&circle1, 5.0f); 98 99 b2RevoluteJointDef jd1; 100 jd1.bodyA = ground; 101 jd1.bodyB = body1; 102 jd1.localAnchorA = ground->GetLocalPoint(bd1.position); 103 jd1.localAnchorB = body1->GetLocalPoint(bd1.position); 104 jd1.referenceAngle = body1->GetAngle() - ground->GetAngle(); 105 m_joint1 = (b2RevoluteJoint*)m_world->CreateJoint(&jd1); 106 107 b2BodyDef bd2; 108 bd2.type = b2_dynamicBody; 109 bd2.position.Set(0.0f, 12.0f); 110 b2Body* body2 = m_world->CreateBody(&bd2); 111 body2->CreateFixture(&circle2, 5.0f); 112 113 b2RevoluteJointDef jd2; 114 jd2.Initialize(ground, body2, bd2.position); 115 m_joint2 = (b2RevoluteJoint*)m_world->CreateJoint(&jd2); 116 117 b2BodyDef bd3; 118 bd3.type = b2_dynamicBody; 119 bd3.position.Set(2.5f, 12.0f); 120 b2Body* body3 = m_world->CreateBody(&bd3); 121 body3->CreateFixture(&box, 5.0f); 122 123 b2PrismaticJointDef jd3; 124 jd3.Initialize(ground, body3, bd3.position, b2Vec2(0.0f, 1.0f)); 125 jd3.lowerTranslation = -5.0f; 126 jd3.upperTranslation = 5.0f; 127 jd3.enableLimit = true; 128 129 m_joint3 = (b2PrismaticJoint*)m_world->CreateJoint(&jd3); 130 131 b2GearJointDef jd4; 132 jd4.bodyA = body1; 133 jd4.bodyB = body2; 134 jd4.joint1 = m_joint1; 135 jd4.joint2 = m_joint2; 136 jd4.ratio = circle2.m_radius / circle1.m_radius; 137 m_joint4 = (b2GearJoint*)m_world->CreateJoint(&jd4); 138 139 b2GearJointDef jd5; 140 jd5.bodyA = body2; 141 jd5.bodyB = body3; 142 jd5.joint1 = m_joint2; 143 jd5.joint2 = m_joint3; 144 jd5.ratio = -1.0f / circle2.m_radius; 145 m_joint5 = (b2GearJoint*)m_world->CreateJoint(&jd5); 146 } 147 } 148 Keyboard(unsigned char key)149 void Keyboard(unsigned char key) 150 { 151 switch (key) 152 { 153 case 0: 154 break; 155 } 156 } 157 Step(Settings * settings)158 void Step(Settings* settings) 159 { 160 Test::Step(settings); 161 162 float32 ratio, value; 163 164 ratio = m_joint4->GetRatio(); 165 value = m_joint1->GetJointAngle() + ratio * m_joint2->GetJointAngle(); 166 m_debugDraw.DrawString(5, m_textLine, "theta1 + %4.2f * theta2 = %4.2f", (float) ratio, (float) value); 167 m_textLine += 15; 168 169 ratio = m_joint5->GetRatio(); 170 value = m_joint2->GetJointAngle() + ratio * m_joint3->GetJointTranslation(); 171 m_debugDraw.DrawString(5, m_textLine, "theta2 + %4.2f * delta = %4.2f", (float) ratio, (float) value); 172 m_textLine += 15; 173 } 174 Create()175 static Test* Create() 176 { 177 return new Gears; 178 } 179 180 b2RevoluteJoint* m_joint1; 181 b2RevoluteJoint* m_joint2; 182 b2PrismaticJoint* m_joint3; 183 b2GearJoint* m_joint4; 184 b2GearJoint* m_joint5; 185 }; 186 187 #endif 188