#include <irr/irrlicht.h>

using namespace irr;


video::IImage* heightmap;
video::IImage* brush;

scene::ITerrainSceneNode* terrain;

/*==============================================================================
  Receiver class
==============================================================================*/
class MyEventReceiver : public IEventReceiver {
    bool KeyIsDown[KEY_KEY_CODES_COUNT];
    bool LEFTBUTTONCLICKED;
    bool RIGHTBUTTONCLICKED;

    public:
        virtual bool OnEvent(const SEvent& event){
            if (event.EventType == irr::EET_KEY_INPUT_EVENT)
                KeyIsDown[event.KeyInput.Key] = event.KeyInput.PressedDown;

            if(event.EventType == EET_MOUSE_INPUT_EVENT){
                if(event.MouseInput.Event==EMIE_LMOUSE_PRESSED_DOWN) LEFTBUTTONCLICKED = true;
                else if(event.MouseInput.Event==EMIE_LMOUSE_LEFT_UP) LEFTBUTTONCLICKED = false;
                else if(event.MouseInput.Event==EMIE_RMOUSE_PRESSED_DOWN) RIGHTBUTTONCLICKED = true;
                else if(event.MouseInput.Event==EMIE_RMOUSE_LEFT_UP) RIGHTBUTTONCLICKED = false;
            }

            return false;
        }

        virtual bool IsKeyDown(EKEY_CODE keyCode) const { return KeyIsDown[keyCode]; }
        virtual bool IsLMBDown() const { return LEFTBUTTONCLICKED; }
        virtual bool IsRMBDown() const { return RIGHTBUTTONCLICKED; }

        MyEventReceiver(){
            for (u32 i=0; i<KEY_KEY_CODES_COUNT; ++i)
                KeyIsDown[i] = false;

            LEFTBUTTONCLICKED = RIGHTBUTTONCLICKED = false;
        }
};

/*==============================================================================
  Raise or lower terrain (selected vertice)
==============================================================================*/
void RaiseTerrainVertex(s32 index, f32 step, bool up){
    scene::IMesh* pMesh = terrain->getMesh();

    s32 heightmapWidth = heightmap->getDimension().Width;
    s32 heightmapHeight = heightmap->getDimension().Height;

    s32 b;
    for (b=0; b<pMesh->getMeshBufferCount(); ++b){
        scene::IMeshBuffer* pMeshBuffer = pMesh->getMeshBuffer(b);
        // skip mesh buffers that are not the right type
        if (pMeshBuffer->getVertexType() != video::EVT_2TCOORDS) continue;

        video::S3DVertex2TCoords* pVertices = (video::S3DVertex2TCoords*)pMeshBuffer->getVertices();

        s32 brushWidth = brush->getDimension().Width;
        s32 brushHeight = brush->getDimension().Height;

        for(int y = 0; y < brushHeight; y++){
            for(int x = 0; x < brushWidth; x++){
                video::SColor brushPixel = brush->getPixel(x, y);

                if((index-(brushWidth/2)-((brushWidth/2)*heightmapWidth) + (x+(y*heightmapWidth))) >= 0){
                    f32 hy = pVertices[index-(brushWidth/2)-((brushWidth/2)*heightmapWidth) + (x+(y*heightmapWidth))].Pos.Y;
                    f32 bp = brushPixel.getRed()/255.0*step;
                    bp = (up)?bp:-bp;

                    if(bp > 0 && hy+bp <= 255)
                        pVertices[index-(brushWidth/2)-((brushWidth/2)*heightmapWidth) + (x+(y*heightmapWidth))].Pos.Y = hy+bp;
                }
            }
        }
    }

    // force terrain render buffer to reload
    terrain->setPosition(terrain->getPosition());
}

/*==============================================================================
  Save file
==============================================================================*/
void save (video::IVideoDriver* driver){
    s32 heightmapWidth = heightmap->getDimension().Width;
    s32 heightmapHeight = heightmap->getDimension().Height;

    const core::dimension2d<u32> dim (heightmapWidth, heightmapHeight);
    video::IImage *img = driver->createImage(video::ECF_A8R8G8B8, dim);

    video::S3DVertex2TCoords* verts = (video::S3DVertex2TCoords*)terrain->getMesh()->getMeshBuffer(0)->getVertices();

    for (u32 y= 0, i = 0; y < heightmapHeight; y++){
        for(u32 x = 0; x < heightmapWidth; i++, x++){
            u8 py = (u8)verts[i].Pos.Y;
            img->setPixel((heightmapHeight-1)-y, x, video::SColor(0, py, py, py));
        }
    }

    driver->writeImageToFile(img, "heightmap.bmp", 0);
    img->drop();
}


int main(){
    MyEventReceiver receiver;

    IrrlichtDevice* device = createDevice(video::EDT_OPENGL, core::dimension2d<u32>(800, 600), 32, false, true, false, &receiver);

    video::IVideoDriver* driver = device->getVideoDriver();
    scene::ISceneManager* smgr = device->getSceneManager();

    device->getCursorControl()->setVisible(false);

    io::path heightmapFile = "heightmap.bmp";
    heightmap = driver->createImageFromFile(heightmapFile);
    brush = driver->createImageFromFile("brush.png");

    terrain = smgr->addTerrainSceneNode(heightmapFile, 0, -1, core::vector3df(0, 0, 0));
    terrain->setScale(core::vector3df(32, 5, 32));
    terrain->setMaterialFlag(video::EMF_LIGHTING, false);

    terrain->setPosition(terrain->getPosition());

    scene::ITriangleSelector* selector = smgr->createTerrainTriangleSelector(terrain, 0);

    // Arrow
    scene::ISceneNode* arrow = smgr->addAnimatedMeshSceneNode(smgr->addArrowMesh("arrow", video::SColor(255, 255, 0, 0), video::SColor(255, 0, 255, 0)), NULL);
    arrow->setMaterialFlag(video::EMF_LIGHTING, false);
    arrow->setScale(core::vector3df(10, 10, 10));
    arrow->setRotation(core::vector3df(0,0,180));

    scene::ICameraSceneNode* cam = smgr->addCameraSceneNodeFPS(0, 100.0f, .1f);
    cam->setPosition(core::vector3df(-100,500,100));
    cam->setTarget(core::vector3df(0,0,0));

    ITimer* irrTimer = device->getTimer();
    u32 then = 0, then30 = 0;
    char c[24];
    f32 step = 2.f;
    bool wireframe = false;

    while(device->run()){
        if(device->isWindowActive()){
            u32 now = irrTimer->getTime();

            if (then30 < now){
                if(receiver.IsKeyDown(irr::KEY_ESCAPE)) break;

                if (receiver.IsKeyDown(irr::KEY_KEY_W) && then < now){
                    wireframe = !wireframe;
                    terrain->setMaterialFlag(video::EMF_WIREFRAME, wireframe);

                    then = now + 300;
                }

                if (receiver.IsKeyDown(irr::KEY_F4) && then < now){
                    step += 1.f;

                    then = now + 100;
                } else if (receiver.IsKeyDown(irr::KEY_F5) && then < now && step > 0){
                    step -= 1.f;

                    then = now + 100;
                }

                if(receiver.IsKeyDown(irr::KEY_KEY_S))
                    save (driver);

                // move the arrow to the nearest vertex ...
                //400, 300 si la résolution utilisée est 800x600
                const core::position2di clickPosition = core::position2di(400, 300);
                const core::line3df ray = smgr->getSceneCollisionManager()->getRayFromScreenCoordinates(clickPosition, cam);
                core::vector3df pos;
                core::triangle3df Tri;

                const scene::ISceneNode* out;
                if (smgr->getSceneCollisionManager()->getCollisionPoint(ray, selector, pos, Tri, out)){
                    //arrow->setPosition(pos);
                    static const s32 scale = 32; // terrain is scaled 32X
                    static const s32 size = 512; // heightmap is 256X256 pixels
                    s32 x = (s32)(pos.X / scale);
                    s32 z = (s32)(pos.Z / scale);
                    s32 index = x * size + z;

                    // ... Move it if clicked
                    if(receiver.IsLMBDown() || receiver.IsRMBDown() && then < now){
                        RaiseTerrainVertex(index, step, receiver.IsLMBDown());
                        then = now + 100;
                    }

                    x *= scale;
                    z *= scale;

                    arrow->setPosition(core::vector3df(x, terrain->getHeight(x, z) + 20, z));
                }

                driver->beginScene(true, true, video::SColor(255, 255, 255, 255));
                smgr->drawAll();
                driver->endScene();

                then30 = now + 30;
            }
        }
    }

    heightmap->drop();
    brush->drop();

    device->closeDevice();
    device->drop();

    return 0;
}