slider_crank_1.cpp

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// 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 "test.h"

// A basic slider crank created for GDC tutorial: Understanding Constraints
class SliderCrank1 : public Test
{
public:
        SliderCrank1()
        {
                b2Body* ground = NULL;
                {
                        b2BodyDef bd;
            bd.position.Set(0.0f, 17.0f);
                        ground = m_world->CreateBody(&bd);
                }
        
                {
                        b2Body* prevBody = ground;
            
                        // Define crank.
                        {
                                b2PolygonShape shape;
                                shape.SetAsBox(4.0f, 1.0f);
                
                                b2BodyDef bd;
                                bd.type = b2_dynamicBody;
                                bd.position.Set(-8.0f, 20.0f);
                                b2Body* body = m_world->CreateBody(&bd);
                                body->CreateFixture(&shape, 2.0f);
                
                                b2RevoluteJointDef rjd;
                                rjd.Initialize(prevBody, body, b2Vec2(-12.0f, 20.0f));
                                m_world->CreateJoint(&rjd);
                
                                prevBody = body;
                        }
            
                        // Define connecting rod
                        {
                                b2PolygonShape shape;
                                shape.SetAsBox(8.0f, 1.0f);
                
                                b2BodyDef bd;
                                bd.type = b2_dynamicBody;
                                bd.position.Set(4.0f, 20.0f);
                                b2Body* body = m_world->CreateBody(&bd);
                                body->CreateFixture(&shape, 2.0f);
                
                                b2RevoluteJointDef rjd;
                                rjd.Initialize(prevBody, body, b2Vec2(-4.0f, 20.0f));
                                m_world->CreateJoint(&rjd);
                
                                prevBody = body;
                        }
            
                        // Define piston
                        {
                                b2PolygonShape shape;
                                shape.SetAsBox(3.0f, 3.0f);
                
                                b2BodyDef bd;
                                bd.type = b2_dynamicBody;
                                bd.fixedRotation = true;
                                bd.position.Set(12.0f, 20.0f);
                                b2Body* body = m_world->CreateBody(&bd);
                                body->CreateFixture(&shape, 2.0f);
                
                                b2RevoluteJointDef rjd;
                                rjd.Initialize(prevBody, body, b2Vec2(12.0f, 20.0f));
                                m_world->CreateJoint(&rjd);
                
                                b2PrismaticJointDef pjd;
                                pjd.Initialize(ground, body, b2Vec2(12.0f, 17.0f), b2Vec2(1.0f, 0.0f));
                                m_world->CreateJoint(&pjd);
                        }
                }
        }
    
        static Test* Create()
        {
                return new SliderCrank1;
        }
};

static int testIndex = RegisterTest("Examples", "Slider Crank 1", SliderCrank1::Create);