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

/*
* Copyright (c) 2011 Erin Catto http://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 ROPE_H
#define ROPE_H

///
class Rope : public Test
{
public:
    Rope()
    {
        const int32 N = 40;
        b2Vec2 vertices[N];
        float32 masses[N];

        for (int32 i = 0; i < N; ++i)
        {
            vertices[i].Set(0.0f, 20.0f - 0.25f * i);
            masses[i] = 1.0f;
        }
        masses[0] = 0.0f;
        masses[1] = 0.0f;

        b2RopeDef def;
        def.vertices = vertices;
        def.count = N;
        def.gravity.Set(0.0f, -10.0f);
        def.masses = masses;
        def.damping = 0.1f;
        def.k2 = 1.0f;
        def.k3 = 0.5f;

        m_rope.Initialize(&def);

        m_angle = 0.0f;
        m_rope.SetAngle(m_angle);
    }

    void Keyboard(unsigned char key)
    {
        switch (key)
        {
        case 'q':
            m_angle = b2Max(-b2_pi, m_angle - 0.05f * b2_pi);
            m_rope.SetAngle(m_angle);
            break;

        case 'e':
            m_angle = b2Min(b2_pi, m_angle + 0.05f * b2_pi);
            m_rope.SetAngle(m_angle);
            break;
        }
    }

    void Step(Settings* settings)
    {
        float32 dt = settings->hz > 0.0f ? 1.0f / settings->hz : 0.0f;

        if (settings->pause == 1 && settings->singleStep == 0)
        {
            dt = 0.0f;
        }

        m_rope.Step(dt, 1);

        Test::Step(settings);

        m_rope.Draw(&m_debugDraw);

        m_debugDraw.DrawString(5, m_textLine, "Press (q,e) to adjust target angle");
        m_textLine += 15;
        m_debugDraw.DrawString(5, m_textLine, "Target angle = %g degrees", m_angle * 180.0f / b2_pi);
        m_textLine += 15;
    }

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

    b2Rope m_rope;
    float32 m_angle;
};

#endif