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;
}