JUCE/examples/Assets/Box2DTests/OneSidedPlatform.h

/*
* Copyright (c) 2008-2009 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 ONE_SIDED_PLATFORM_H
#define ONE_SIDED_PLATFORM_H

class OneSidedPlatform : public Test
{
public:

    enum State
    {
        e_unknown,
        e_above,
        e_below
    };

    OneSidedPlatform()
    {
        // Ground
        {
            b2BodyDef bd;
            b2Body* ground = m_world->CreateBody(&bd);

            b2EdgeShape shape;
            shape.Set(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));
            ground->CreateFixture(&shape, 0.0f);
        }

        // Platform
        {
            b2BodyDef bd;
            bd.position.Set(0.0f, 10.0f);
            b2Body* body = m_world->CreateBody(&bd);

            b2PolygonShape shape;
            shape.SetAsBox(3.0f, 0.5f);
            m_platform = body->CreateFixture(&shape, 0.0f);

            m_bottom = 10.0f - 0.5f;
            m_top = 10.0f + 0.5f;
        }

        // Actor
        {
            b2BodyDef bd;
            bd.type = b2_dynamicBody;
            bd.position.Set(0.0f, 12.0f);
            b2Body* body = m_world->CreateBody(&bd);

            m_radius = 0.5f;
            b2CircleShape shape;
            shape.m_radius = m_radius;
            m_character = body->CreateFixture(&shape, 20.0f);

            body->SetLinearVelocity(b2Vec2(0.0f, -50.0f));

            m_state = e_unknown;
        }
    }

    void PreSolve(b2Contact* contact, const b2Manifold* oldManifold)
    {
        Test::PreSolve(contact, oldManifold);

        b2Fixture* fixtureA = contact->GetFixtureA();
        b2Fixture* fixtureB = contact->GetFixtureB();

        if (fixtureA != m_platform && fixtureA != m_character)
        {
            return;
        }

        if (fixtureB != m_platform && fixtureB != m_character)
        {
            return;
        }

        b2Vec2 position = m_character->GetBody()->GetPosition();

        if (position.y < m_top + m_radius - 3.0f * b2_linearSlop)
        {
            contact->SetEnabled(false);
        }
    }

    void Step(Settings* settings)
    {
        Test::Step(settings);
        m_debugDraw.DrawString(5, m_textLine, "Press: (c) create a shape, (d) destroy a shape.");
        m_textLine += 15;
    }

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

    float32 m_radius, m_top, m_bottom;
    State m_state;
    b2Fixture* m_platform;
    b2Fixture* m_character;
};

#endif