Ogre中手动创建mesh

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在一个可以正常运行的ogre程序里边，找到createscene函数，添加如下代码：

//定义对象并设置材质名称与绘制模式

ManualObject* manual = mSceneMgr->createManualObject("manual");

manual->begin("BaseWhiteNoLighting", nderOperation::OT_LINE_STRIP);

bool test = false;

if(test)

{

//平面

//指定定点位置

manual->position(-100.0, -100.0, 0.0);

manual->position( 100.0, -100.0, 0.0);

manual->position( 100.0, 100.0, 0.0);

manual->position(-100.0, 100.0, 0.0);

manual->position(0,200.0,0);

//指定索引顺序，就是绘制定点的顺序，如果不指定就一句定点列出的顺序依次绘制

manual->index(0);

manual->index(1);

manual->index(2);

manual->index(4);

manual->index(3);

manual->index(0);

}

else

{

//立方体

//指定定点位置

manual->position(-100.0, -100.0, 100.0);

manual->position( 100.0, -100.0, 100.0);

manual->position( 100.0, -100.0, -100.0);

manual->position(-100.0, -100.0, -100.0);

manual->position(-100.0, 100.0,100.0);

manual->position( 100.0, 100.0, 100.0);

manual->position(100.0, 100.0, -100.0);

manual->position(-100,100.0,-100);

//指定索引顺序，就是绘制定点的顺序，如果不指定就一句定点列出的顺序依次绘制

manual->index(0);

manual->index(1);

manual->index(2);

manual->index(3);

manual->index(0);

manual->index(4);

manual->index(5);

manual->index(6);

manual->index(7);

manual->index(4);

manual->index(7);

manual->index(3);

manual->index(2);

manual->index(6);

manual->index(5);

manual->index(1);

}

manual->end(); //结束定点设置。这里的begin和end对应于d3d中读写定点缓存时的loack 与 unlock !

//将手动对象创建为mesh

manual->convertToMesh("testMesh");

Entity * tempEntity = SceneMgr->createEntity("cube","testMesh");

mSceneMgr->getRootSceneNode()->createChildSceneNode()->attachObject(tempEntity);

//也可以不创建mesh，直接将对象挂在节点也是可以显示的

mSceneMgr->getRootSceneNode()->createChildSceneNode()->attachObject(manual)

绘制模式参数设置参看参看

http://www.ogre3d.org/wiki/index.php/ManualObject

Ogre手动创建mesh（N个submesh）

Mesh与submesh以及创建submesh中数据项之间的关系如下：

下面是代码示例：

在程序中加入如下2个函数：

//为mesh创建2个submesh，并填充submesh的数据。

void createColourCube()

{

/// 从mesh管理器中创建mesh

Ogre::MeshPtr msh = MeshManager::getSingleton().createManual("ColourCube", "General");

//mesh包含2个子实体

SubMesh * sub1 = msh->createSubMesh("2");

SubMesh * sub2 = msh->createSubMesh("1");

//分别为个子实体填充数据

fillSubMesh(sub1,1); //fill函数在后边定义

fillSubMesh(sub2,2);

/// Set bounding information (for culling)

msh->_setBounds(AxisAlignedBox(-100,-100,-100,100,100,100));

msh->_setBoundingSphereRadius(Math::Sqrt(3*100*100));

/// Notify Mesh object that it has been loaded

msh->load();

}

//填充顶点的所需要的信息，并写入缓存

void fillSubMesh(SubMesh * submeshPtr, int i)

{

//填充子实体所需的数据项

//法线

const float sqrt13 = 0.577350269f; /* sqrt(1/3) */

/// Define the vertices (8 vertices, each consisting of 2 groups of 3 floats

const size_t nVertices = 8;

const size_t vbufCount = 3*2*nVertices;

float vertices[vbufCount] = {

-100.0,100.0,-100.0, //0 position

-sqrt13,sqrt13,-sqrt13, //0 normal

100.0,100.0,-100.0, //1 position

sqrt13,sqrt13,-sqrt13, //1 normal

100.0,-100.0,-100.0, //2 position

sqrt13,-sqrt13,-sqrt13, //2 normal

-100.0,-100.0,-100.0, //3 position

-sqrt13,-sqrt13,-sqrt13, //3 normal

-100.0,100.0,100.0, //4 position

-sqrt13,sqrt13,sqrt13, //4 normal

100.0,100.0,100.0, //5 position

sqrt13,sqrt13,sqrt13, //5 normal

100.0,-100.0,100.0, //6 position

sqrt13,-sqrt13,sqrt13, //6 normal

-100.0,-100.0,100.0, //7 position

-sqrt13,-sqrt13,sqrt13, //7 normal

};

float vertices2[vbufCount] = {

200.0,100.0,-100.0, //0 position

-sqrt13,sqrt13,-sqrt13, //0 normal

400.0,100.0,-100.0, //1 position

sqrt13,sqrt13,-sqrt13, //1 normal

400.0,-100.0,-100.0, //2 position

sqrt13,-sqrt13,-sqrt13, //2 normal

200.0,-100.0,-100.0, //3 position

-sqrt13,-sqrt13,-sqrt13, //3 normal

200.0,100.0,100.0, //4 position

-sqrt13,sqrt13,sqrt13, //4 normal

400.0,100.0,100.0, //5 position

sqrt13,sqrt13,sqrt13, //5 normal

400.0,-100.0,100.0, //6 position

sqrt13,-sqrt13,sqrt13, //6 normal

200.0,-100.0,100.0, //7 position

-sqrt13,-sqrt13,sqrt13, //7 normal

};

//给每个点点设置颜色

RenderSystem* rs = Root::getSingleton().getRenderSystem();

RGBA colours[nVertices];

RGBA *pColour = colours;

// Use render system to convert colour value since colour packing varies

rs->convertColourValue(ColourValue(1.0,0.0,0.0), pColour++); //0 colour

rs->convertColourValue(ColourValue(1.0,1.0,0.0), pColour++); //1 colour

rs->convertColourValue(ColourValue(0.0,1.0,0.0), pColour++); //2 colour

rs->convertColourValue(ColourValue(0.0,0.0,0.0), pColour++); //3 colour

rs->convertColourValue(ColourValue(1.0,0.0,1.0), pColour++); //4 colour

rs->convertColourValue(ColourValue(1.0,1.0,1.0), pColour++); //5 colour

rs->convertColourValue(ColourValue(0.0,1.0,1.0), pColour++); //6 colour

rs->convertColourValue(ColourValue(0.0,0.0,1.0), pColour++); //7 colour

/// 定义个面所需要的个三角形的索引顺序

const size_t ibufCount = 36;

unsigned short faces[ibufCount] = {

0,2,3,

0,1,2,

1,6,2,

1,5,6,

4,6,5,

4,7,6,

0,7,4,

0,3,7,

0,5,1,

0,4,5,

2,7,3,

2,6,7

};

/// 为子实体创建存储定点数据的空间以及指定顶点的数量

submeshPtr->vertexData = new VertexData();

submeshPtr->vertexData->vertexCount = nVertices;

// Create declaration (memory format) of vertex data

//指定顶点使用的格式

VertexDeclaration* decl = submeshPtr->vertexData->vertexDeclaration;

size_t offset = 0;

// 1st buffer

//写入顶点坐标数据信息

decl->addElement(0, offset, VET_FLOAT3, VES_POSITION);

offset += VertexElement::getTypeSize(VET_FLOAT3);

decl->addElement(0, offset, VET_FLOAT3, VES_NORMAL);

offset += VertexElement::getTypeSize(VET_FLOAT3);

/// Allocate vertex buffer of the requested number of vertices (vertexCount)

/// and bytes per vertex (offset)

//分配顶点所需要的硬件缓冲

HardwareVertexBufferSharedPtr vbuf =

HardwareBufferManager::getSingleton().createVertexBuffer(

offset, submeshPtr->vertexData->vertexCount, HardwareBuffer::HBU_STATIC_WRITE_ONLY);

/// Upload the vertex data to the card

//将数据写入缓存

if(i == 1)

{

vbuf->writeData(0, vbuf->getSizeInBytes(), vertices, true); //将顶点信息写入缓存

}

if(i == 2)

{

vbuf->writeData(0, vbuf->getSizeInBytes(), vertices2, true); //将顶点信息写入缓存

}

/// Set vertex buffer binding so buffer 0 is bound to our vertex buffer

VertexBufferBinding* bind = submeshPtr->vertexData->vertexBufferBinding;

bind->setBinding(0, vbuf);

//顶点颜色缓存创建

offset = 0;

decl->addElement(1, offset, VET_COLOUR, VES_DIFFUSE);

offset += VertexElement::getTypeSize(VET_COLOUR);

/// Allocate vertex buffer of the requested number of vertices (vertexCount)

/// and bytes per vertex (offset)

vbuf = HardwareBufferManager::getSingleton().createVertexBuffer(

offset, submeshPtr->vertexData->vertexCount, HardwareBuffer::HBU_STATIC_WRITE_ONLY);

/// Upload the vertex data to the card

vbuf->writeData(0, vbuf->getSizeInBytes(), colours, true);

/// Set vertex buffer binding so buffer 1 is bound to our colour buffer

bind->setBinding(1, vbuf);

//创建索引缓存并写入

/// Allocate index buffer of the requested number of vertices (ibufCount)

HardwareIndexBufferSharedPtr ibuf = HardwareBufferManager::getSingleton().createIndexBuffer( HardwareIndexBuffer::IT_16BIT, ibufCount,

HardwareBuffer::HBU_STATIC_WRITE_ONLY);

// Upload the index data to the card

ibuf->writeData(0, ibuf->getSizeInBytes(), faces, true);

// Set parameters of the submesh

submeshPtr->useSharedVertices = false;

submeshPtr->indexData->indexBuffer = ibuf;

submeshPtr->indexData->indexCount = ibufCount;

submeshPtr->indexData->indexStart = 0;

}

然后在createscene函数中加入如下代码：

createColourCube();//创建数据

Entity* thisEntity = mSceneMgr->createEntity("cc", "ColourCube");

thisEntity->getSubEntity("1")->setMaterialName("Test/ColourTest");

thisEntity->getSubEntity("2")->setMaterialName("Test/ColourTest");

SceneNode* thisSceneNode = mSceneMgr->getRootSceneNode()->createChildSceneNode();

thisSceneNode->setPosition(-35, 0, 0);

thisSceneNode->attachObject(thisEntity);

然后再将下面的材质脚本加入到ogre的General资源组中：

material Test/ColourTest

{

technique

{

pass

{

ambient vertexcolour

}

之后编译运行，你可以看到有2个彩色的立方体在摄像机前面。下面给出过程总结：

1. 从mesh创建submesh。

2. 为submesh的各个数据结构分配空间并设置。

主要有如下几项：vertexdata,indexdata.

3. 为vertexdata指定顶点格式以及为其分配硬件缓存并与之绑定。

4. 分配indexdata的硬件空间和colorvalue的硬件空间。

5. 分别将对应的vertexdata,indexdata,colorvalue写入对应的缓存。

6. 之后做一些设置。如果没有使用mesh的共享缓存，则要关闭submesh的使用共享缓存设置。