开源3D游戏引擎Irrlicht简介

Irrlicht简介

Irrlicht在国内也被叫做“鬼火”引擎，是一款用C++编写的开放源代码的高性能游戏引擎。而且是跨平台的，具有很好的移植性，Irrlicht支持OpenGl、Direcx3D渲染，引擎本身也实现了一套自己的渲染系统。在商业引擎中能够找到的艺术特性，Irrlicht基本都支持。目前有很多项目中都使用到它，Irrlicht社区也比较活跃，可以在互联网上找到不少Irrlicht增强工具，例如irrEdit、irrKlang等。在众多开源游戏引擎中，Irrlicht也是比较受笔者青睐的一款。

Irrlicht官方网站：http://irrlicht.sourceforge.net/

Irrlicht下载与使用

Irrlicht目前最新稳定版本为1.8.1，项目发布在sourceforge平台上，用户可以通过sourceforge网站首页面搜索功能找到Irrlicht项目下载地址，或者从Irrlicht官网获取下载链接。

下载地址：http://irrlicht.sourceforge.net/downloads/

1.目录结构

解压后目录结构如下：

bin：不同平台编译Irrlicht生成的可执行文件和动态库文件放在该目录中。

doc : 该目录中为Irrlicht API文档。

examples ： Irrlicht官方提供的案例程序存放在该目录中。

include ：存放引擎所有头文件。

lib : 该目录存放Irrlicht引擎编译过后生成的静态库。

media ：官方案例所需资源文件存放在此目录中。

source ：存放引擎源码。

tools : 该目录下为Irrlicht引擎相关工具。如irrEdit、GUIEditor等。

2.官方案例

Irrlicht使用起来是非常方便的，这也是笔者比较喜欢它的原因之一。为了方便用户学习和使用引擎，Irrlicht官方提供了大量的例子程序，而且都比较具有代表性。

打开examples目录，Irrlicht已经为目前主流开发工具Windows平台下Visual Studio、MacOS下的Xcode以及Linux平台下的GNU MAKE做好了项目配置。

笔者是在Windows操作系统下使用VS2012进行演示，双击BuildAllExamples_vc11.sln打开解决方案，无需做任何配置即可编译运行程序。

编译运行Collision案例程序：

看起来效果是不是很炫呢?Irrlicht为我们做了大量的封装，即便看似如此复杂的程序，实际代码不超过200行。

#include <irrlicht.h>

#include "driverChoice.h"

using namespace irr;

#ifdef _MSC_VER

#pragma comment(lib, "Irrlicht.lib")

#endif

enum

{

    ID_IsNotPickable = 0,

    IDFlag_IsPickable = 1 << 0,

    IDFlag_IsHighlightable = 1 << 1

};

int main()

{

    video::E_DRIVER_TYPE driverType=video::EDT_OPENGL;//driverChoiceConsole();

    if (driverType==video::EDT_COUNT)

        return 1;

    IrrlichtDevice *device =

        createDevice(driverType, core::dimension2d<u32>(1024, 768), 16, false);

    if (device == 0)

        return 1; // could not create selected driver.

    video::IVideoDriver* driver = device->getVideoDriver();

    scene::ISceneManager* smgr = device->getSceneManager();

    device->getFileSystem()->addFileArchive("../../media/map-20kdm2.pk3");

    scene::IAnimatedMesh* q3levelmesh = smgr->getMesh("20kdm2.bsp");

    scene::IMeshSceneNode* q3node = 0;

    if (q3levelmesh)

        q3node = smgr->addOctreeSceneNode(q3levelmesh->getMesh(0), 0, IDFlag_IsPickable);

    scene::ITriangleSelector* selector = 0;

    if (q3node)

    {

        q3node->setPosition(core::vector3df(-1350,-130,-1400));

        selector = smgr->createOctreeTriangleSelector(

                q3node->getMesh(), q3node, 128);

        q3node->setTriangleSelector(selector);

    }

    scene::ICameraSceneNode* camera =

        smgr->addCameraSceneNodeFPS(0, 100.0f, .3f, ID_IsNotPickable, 0, 0, true, 3.f);

    camera->setPosition(core::vector3df(50,50,-60));

    camera->setTarget(core::vector3df(-70,30,-60));

    if (selector)

    {

        scene::ISceneNodeAnimator* anim = smgr->createCollisionResponseAnimator(

            selector, camera, core::vector3df(30,50,30),

            core::vector3df(0,-10,0), core::vector3df(0,30,0));

        selector->drop(); // As soon as we're done with the selector, drop it.

        camera->addAnimator(anim);

        anim->drop();

    }

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

    scene::IBillboardSceneNode * bill = smgr->addBillboardSceneNode();

    bill->setMaterialType(video::EMT_TRANSPARENT_ADD_COLOR );

    bill->setMaterialTexture(0, driver->getTexture("../../media/particle.bmp"));

    bill->setMaterialFlag(video::EMF_LIGHTING, false);

    bill->setMaterialFlag(video::EMF_ZBUFFER, false);

    bill->setSize(core::dimension2d<f32>(20.0f, 20.0f));

    bill->setID(ID_IsNotPickable); // This ensures that we don't accidentally ray-pick it

    scene::IAnimatedMeshSceneNode* node = 0;

    video::SMaterial material;

    node = smgr->addAnimatedMeshSceneNode(smgr->getMesh("../../media/faerie.md2"),

                        0, IDFlag_IsPickable | IDFlag_IsHighlightable);

    node->setPosition(core::vector3df(-90,-15,-140)); // Put its feet on the floor.

    node->setScale(core::vector3df(1.6f)); // Make it appear realistically scaled

    node->setMD2Animation(scene::EMAT_POINT);

    node->setAnimationSpeed(20.f);

    material.setTexture(0, driver->getTexture("../../media/faerie2.bmp"));

    material.Lighting = true;

    material.NormalizeNormals = true;

    node->getMaterial(0) = material;

    selector = smgr->createTriangleSelector(node);

    node->setTriangleSelector(selector);

    selector->drop(); // We're done with this selector, so drop it now.

    node = smgr->addAnimatedMeshSceneNode(smgr->getMesh("../../media/ninja.b3d"),

                        0, IDFlag_IsPickable | IDFlag_IsHighlightable);

    node->setScale(core::vector3df(10));

    node->setPosition(core::vector3df(-75,-66,-80));

    node->setRotation(core::vector3df(0,90,0));

    node->setAnimationSpeed(8.f);

    node->getMaterial(0).NormalizeNormals = true;

    node->getMaterial(0).Lighting = true;

    selector = smgr->createTriangleSelector(node);

    node->setTriangleSelector(selector);

    selector->drop();

    node = smgr->addAnimatedMeshSceneNode(smgr->getMesh("../../media/dwarf.x"),

                        0, IDFlag_IsPickable | IDFlag_IsHighlightable);

    node->setPosition(core::vector3df(-70,-66,-30)); // Put its feet on the floor.

    node->setRotation(core::vector3df(0,-90,0)); // And turn it towards the camera.

    node->setAnimationSpeed(20.f);

    node->getMaterial(0).Lighting = true;

    selector = smgr->createTriangleSelector(node);

    node->setTriangleSelector(selector);

    selector->drop();

    node = smgr->addAnimatedMeshSceneNode(smgr->getMesh("../../media/yodan.mdl"),

                        0, IDFlag_IsPickable | IDFlag_IsHighlightable);

    node->setPosition(core::vector3df(-90,-25,20));

    node->setScale(core::vector3df(0.8f));

    node->getMaterial(0).Lighting = true;

    node->setAnimationSpeed(20.f);

    // Just do the same as we did above.

    selector = smgr->createTriangleSelector(node);

    node->setTriangleSelector(selector);

    selector->drop();

    material.setTexture(0, 0);

    material.Lighting = false;

    scene::ILightSceneNode * light = smgr->addLightSceneNode(0, core::vector3df(-60,100,400),

        video::SColorf(1.0f,1.0f,1.0f,1.0f), 600.0f);

    light->setID(ID_IsNotPickable); // Make it an invalid target for selection.

    scene::ISceneNode* highlightedSceneNode = 0;

    scene::ISceneCollisionManager* collMan = smgr->getSceneCollisionManager();

    int lastFPS = -1;

    material.Wireframe=true;

    while(device->run())

    if (device->isWindowActive())

    {

        driver->beginScene(true, true, 0);

        smgr->drawAll();

        if (highlightedSceneNode)

        {

            highlightedSceneNode->setMaterialFlag(video::EMF_LIGHTING, true);

            highlightedSceneNode = 0;

        }

        core::line3d<f32> ray;

        ray.start = camera->getPosition();

        ray.end = ray.start + (camera->getTarget() - ray.start).normalize() * 1000.0f;

        core::vector3df intersection;

        core::triangle3df hitTriangle;

        scene::ISceneNode * selectedSceneNode =

            collMan->getSceneNodeAndCollisionPointFromRay(

                    ray,

                    intersection,

                    hitTriangle,

                    IDFlag_IsPickable,

                    0);

        if(selectedSceneNode)

        {

            bill->setPosition(intersection);

            driver->setTransform(video::ETS_WORLD, core::matrix4());

            driver->setMaterial(material);

            driver->draw3DTriangle(hitTriangle, video::SColor(0,255,0,0));

            if((selectedSceneNode->getID() & IDFlag_IsHighlightable) == IDFlag_IsHighlightable)

            {

                highlightedSceneNode = selectedSceneNode;

                highlightedSceneNode->setMaterialFlag(video::EMF_LIGHTING, false);

            }

        }

        driver->endScene();

        int fps = driver->getFPS();

        if (lastFPS != fps)

        {

            core::stringw str = L"Collision detection example - Irrlicht Engine [";

            str += driver->getName();

            str += "] FPS:";

            str += fps;

            device->setWindowCaption(str.c_str());

            lastFPS = fps;

        }

    }

    device->drop();

    return 0;

}