text: /*
  * 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);
  		}
  
  		{
  			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, 5.0f);
  
  			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 Step(Settings* settings)
  	{
  		Test::Step(settings);
  
  		float32 ratio, value;
  		
  		ratio = m_joint4->GetRatio();
  		value = m_joint1->GetJointAngle() + ratio * m_joint2->GetJointAngle();
  		g_debugDraw.DrawString(5, m_textLine, "theta1 + %4.2f * theta2 = %4.2f", (float) ratio, (float) value);
  		m_textLine += DRAW_STRING_NEW_LINE;
  
  		ratio = m_joint5->GetRatio();
  		value = m_joint2->GetJointAngle() + ratio * m_joint3->GetJointTranslation();
  		g_debugDraw.DrawString(5, m_textLine, "theta2 + %4.2f * delta = %4.2f", (float) ratio, (float) value);
  		m_textLine += DRAW_STRING_NEW_LINE;
  	}
  
  	static Test* Create()
  	{
  		return new Gears;
  	}
  
  	b2RevoluteJoint* m_joint1;
  	b2RevoluteJoint* m_joint2;
  	b2PrismaticJoint* m_joint3;
  	b2GearJoint* m_joint4;
  	b2GearJoint* m_joint5;
  };
  
  #endif
  