JUCE/examples/Demo/Source/Demos/Box2DTests/Prismatic.h

/*
* Copyright (c) 2006-2009 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 PRISMATIC_H
#define PRISMATIC_H

// The motor in this test gets smoother with higher velocity iterations.
class Prismatic : public Test
{
public:
    Prismatic()
    {
        b2Body* ground = NULL;
        {
            b2BodyDef bd;
            ground = m_world->CreateBody(&bd);

            b2EdgeShape shape;
            shape.Set(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f));
            ground->CreateFixture(&shape, 0.0f);
        }

        {
            b2PolygonShape shape;
            shape.SetAsBox(2.0f, 0.5f);

            b2BodyDef bd;
            bd.type = b2_dynamicBody;
            bd.position.Set(-10.0f, 10.0f);
            bd.angle = 0.5f * b2_pi;
            bd.allowSleep = false;
            b2Body* body = m_world->CreateBody(&bd);
            body->CreateFixture(&shape, 5.0f);

            b2PrismaticJointDef pjd;

            // Bouncy limit
            b2Vec2 axis(2.0f, 1.0f);
            axis.Normalize();
            pjd.Initialize(ground, body, b2Vec2(0.0f, 0.0f), axis);

            // Non-bouncy limit
            //pjd.Initialize(ground, body, b2Vec2(-10.0f, 10.0f), b2Vec2(1.0f, 0.0f));

            pjd.motorSpeed = 10.0f;
            pjd.maxMotorForce = 10000.0f;
            pjd.enableMotor = true;
            pjd.lowerTranslation = 0.0f;
            pjd.upperTranslation = 20.0f;
            pjd.enableLimit = true;

            m_joint = (b2PrismaticJoint*)m_world->CreateJoint(&pjd);
        }
    }

    void Keyboard(unsigned char key)
    {
        switch (key)
        {
        case 'l':
            m_joint->EnableLimit(!m_joint->IsLimitEnabled());
            break;

        case 'm':
            m_joint->EnableMotor(!m_joint->IsMotorEnabled());
            break;

        case 's':
            m_joint->SetMotorSpeed(-m_joint->GetMotorSpeed());
            break;
        }
    }

    void Step(Settings* settings)
    {
        Test::Step(settings);
        m_debugDraw.DrawString(5, m_textLine, "Keys: (l) limits, (m) motors, (s) speed");
        m_textLine += 15;
        float32 force = m_joint->GetMotorForce(settings->hz);
        m_debugDraw.DrawString(5, m_textLine, "Motor Force = %4.0f", (float) force);
        m_textLine += 15;
    }

    static Test* Create()
    {
        return new Prismatic;
    }

    b2PrismaticJoint* m_joint;
};

#endif