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

/*
* Copyright (c) 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 DYNAMIC_TREE_TEST_H
#define DYNAMIC_TREE_TEST_H

class DynamicTreeTest : public Test
{
public:

    enum
    {
        e_actorCount = 128
    };

    DynamicTreeTest()
    {
        m_worldExtent = 15.0f;
        m_proxyExtent = 0.5f;

        srand(888);

        for (int32 i = 0; i < e_actorCount; ++i)
        {
            Actor* actor = m_actors + i;
            GetRandomAABB(&actor->aabb);
            actor->proxyId = m_tree.CreateProxy(actor->aabb, actor);
        }

        m_stepCount = 0;

        float32 h = m_worldExtent;
        m_queryAABB.lowerBound.Set(-3.0f, -4.0f + h);
        m_queryAABB.upperBound.Set(5.0f, 6.0f + h);

        m_rayCastInput.p1.Set(-5.0, 5.0f + h);
        m_rayCastInput.p2.Set(7.0f, -4.0f + h);
        //m_rayCastInput.p1.Set(0.0f, 2.0f + h);
        //m_rayCastInput.p2.Set(0.0f, -2.0f + h);
        m_rayCastInput.maxFraction = 1.0f;

        m_automated = false;
    }

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

    void Step(Settings* settings)
    {
        B2_NOT_USED(settings);

        m_rayActor = NULL;
        for (int32 i = 0; i < e_actorCount; ++i)
        {
            m_actors[i].fraction = 1.0f;
            m_actors[i].overlap = false;
        }

        if (m_automated == true)
        {
            int32 actionCount = b2Max(1, e_actorCount >> 2);

            for (int32 i = 0; i < actionCount; ++i)
            {
                Action();
            }
        }

        Query();
        RayCast();

        for (int32 i = 0; i < e_actorCount; ++i)
        {
            Actor* actor = m_actors + i;
            if (actor->proxyId == b2_nullNode)
                continue;

            b2Color c(0.9f, 0.9f, 0.9f);
            if (actor == m_rayActor && actor->overlap)
            {
                c.Set(0.9f, 0.6f, 0.6f);
            }
            else if (actor == m_rayActor)
            {
                c.Set(0.6f, 0.9f, 0.6f);
            }
            else if (actor->overlap)
            {
                c.Set(0.6f, 0.6f, 0.9f);
            }

            m_debugDraw.DrawAABB(&actor->aabb, c);
        }

        b2Color c(0.7f, 0.7f, 0.7f);
        m_debugDraw.DrawAABB(&m_queryAABB, c);

        m_debugDraw.DrawSegment(m_rayCastInput.p1, m_rayCastInput.p2, c);

        b2Color c1(0.2f, 0.9f, 0.2f);
        b2Color c2(0.9f, 0.2f, 0.2f);
        m_debugDraw.DrawPoint(m_rayCastInput.p1, 6.0f, c1);
        m_debugDraw.DrawPoint(m_rayCastInput.p2, 6.0f, c2);

        if (m_rayActor)
        {
            b2Color cr(0.2f, 0.2f, 0.9f);
            b2Vec2 p = m_rayCastInput.p1 + m_rayActor->fraction * (m_rayCastInput.p2 - m_rayCastInput.p1);
            m_debugDraw.DrawPoint(p, 6.0f, cr);
        }

        {
            int32 height = m_tree.GetHeight();
            m_debugDraw.DrawString(5, m_textLine, "dynamic tree height = %d", height);
            m_textLine += 15;
        }

        ++m_stepCount;
    }

    void Keyboard(unsigned char key)
    {
        switch (key)
        {
        case 'a':
            m_automated = !m_automated;
            break;

        case 'c':
            CreateProxy();
            break;

        case 'd':
            DestroyProxy();
            break;

        case 'm':
            MoveProxy();
            break;
        }
    }

    bool QueryCallback(int32 proxyId)
    {
        Actor* actor = (Actor*)m_tree.GetUserData(proxyId);
        actor->overlap = b2TestOverlap(m_queryAABB, actor->aabb);
        return true;
    }

    float32 RayCastCallback(const b2RayCastInput& input, int32 proxyId)
    {
        Actor* actor = (Actor*)m_tree.GetUserData(proxyId);

        b2RayCastOutput output;
        bool hit = actor->aabb.RayCast(&output, input);

        if (hit)
        {
            m_rayCastOutput = output;
            m_rayActor = actor;
            m_rayActor->fraction = output.fraction;
            return output.fraction;
        }

        return input.maxFraction;
    }

private:

    struct Actor
    {
        b2AABB aabb;
        float32 fraction;
        bool overlap;
        int32 proxyId;
    };

    void GetRandomAABB(b2AABB* aabb)
    {
        b2Vec2 w; w.Set(2.0f * m_proxyExtent, 2.0f * m_proxyExtent);
        //aabb->lowerBound.x = -m_proxyExtent;
        //aabb->lowerBound.y = -m_proxyExtent + m_worldExtent;
        aabb->lowerBound.x = RandomFloat(-m_worldExtent, m_worldExtent);
        aabb->lowerBound.y = RandomFloat(0.0f, 2.0f * m_worldExtent);
        aabb->upperBound = aabb->lowerBound + w;
    }

    void MoveAABB(b2AABB* aabb)
    {
        b2Vec2 d;
        d.x = RandomFloat(-0.5f, 0.5f);
        d.y = RandomFloat(-0.5f, 0.5f);
        //d.x = 2.0f;
        //d.y = 0.0f;
        aabb->lowerBound += d;
        aabb->upperBound += d;

        b2Vec2 c0 = 0.5f * (aabb->lowerBound + aabb->upperBound);
        b2Vec2 min; min.Set(-m_worldExtent, 0.0f);
        b2Vec2 max; max.Set(m_worldExtent, 2.0f * m_worldExtent);
        b2Vec2 c = b2Clamp(c0, min, max);

        aabb->lowerBound += c - c0;
        aabb->upperBound += c - c0;
    }

    void CreateProxy()
    {
        for (int32 i = 0; i < e_actorCount; ++i)
        {
            int32 j = rand() % e_actorCount;
            Actor* actor = m_actors + j;
            if (actor->proxyId == b2_nullNode)
            {
                GetRandomAABB(&actor->aabb);
                actor->proxyId = m_tree.CreateProxy(actor->aabb, actor);
                return;
            }
        }
    }

    void DestroyProxy()
    {
        for (int32 i = 0; i < e_actorCount; ++i)
        {
            int32 j = rand() % e_actorCount;
            Actor* actor = m_actors + j;
            if (actor->proxyId != b2_nullNode)
            {
                m_tree.DestroyProxy(actor->proxyId);
                actor->proxyId = b2_nullNode;
                return;
            }
        }
    }

    void MoveProxy()
    {
        for (int32 i = 0; i < e_actorCount; ++i)
        {
            int32 j = rand() % e_actorCount;
            Actor* actor = m_actors + j;
            if (actor->proxyId == b2_nullNode)
            {
                continue;
            }

            b2AABB aabb0 = actor->aabb;
            MoveAABB(&actor->aabb);
            b2Vec2 displacement = actor->aabb.GetCenter() - aabb0.GetCenter();
            m_tree.MoveProxy(actor->proxyId, actor->aabb, displacement);
            return;
        }
    }

    void Action()
    {
        int32 choice = rand() % 20;

        switch (choice)
        {
        case 0:
            CreateProxy();
            break;

        case 1:
            DestroyProxy();
            break;

        default:
            MoveProxy();
        }
    }

    void Query()
    {
        m_tree.Query(this, m_queryAABB);

        for (int32 i = 0; i < e_actorCount; ++i)
        {
            if (m_actors[i].proxyId == b2_nullNode)
            {
                continue;
            }

            bool overlap = b2TestOverlap(m_queryAABB, m_actors[i].aabb);
            B2_NOT_USED(overlap);
            b2Assert(overlap == m_actors[i].overlap);
        }
    }

    void RayCast()
    {
        m_rayActor = NULL;

        b2RayCastInput input = m_rayCastInput;

        // Ray cast against the dynamic tree.
        m_tree.RayCast(this, input);

        // Brute force ray cast.
        Actor* bruteActor = NULL;
        b2RayCastOutput bruteOutput;
        for (int32 i = 0; i < e_actorCount; ++i)
        {
            if (m_actors[i].proxyId == b2_nullNode)
            {
                continue;
            }

            b2RayCastOutput output;
            bool hit = m_actors[i].aabb.RayCast(&output, input);
            if (hit)
            {
                bruteActor = m_actors + i;
                bruteOutput = output;
                input.maxFraction = output.fraction;
            }
        }

        if (bruteActor != NULL)
        {
            b2Assert(bruteOutput.fraction == m_rayCastOutput.fraction);
        }
    }

    float32 m_worldExtent;
    float32 m_proxyExtent;

    b2DynamicTree m_tree;
    b2AABB m_queryAABB;
    b2RayCastInput m_rayCastInput;
    b2RayCastOutput m_rayCastOutput;
    Actor* m_rayActor;
    Actor m_actors[e_actorCount];
    int32 m_stepCount;
    bool m_automated;
};

#endif