DirectX 基础学习系列5 纹理映射

1纹理坐标

类似BMP图像坐标系，左上为原点

纹理坐标为了规范化，范围限定在[0,1]之间，使用纹理的时候，需要修改顶点结构

structColorVetex

{

floatx,y,z;

float_nx,_ny,_nz;

float_u,_y;

staticconstDWORDFVF;

}

constDWORDColorVetex::FVF=D3DFVF_XYZ|D3DFVF_NORMAL|D3DFVF_TEX1;

2创建并启用纹理

从文件中加载纹理数据

HRESULTD3DXCreateTextureFromFile( LPDIRECT3DDEVICE9pDevice, LPCTSTRpSrcFile, LPDIRECT3DTEXTURE9*ppTexture );

从内存中加载

HRESULTD3DXCreateTextureFromFileInMemory( LPDIRECT3DDEVICE9pDevice,LPCVOID pSrcData,UINTSrcDataSize, LPDIRECT3DTEXTURE9*ppTexture);

从资源加载

HRESULTD3DXCreateTextureFromResource( LPDIRECT3DDEVICE9pDevice, HMODULEhSrcModule, LPCTSTRpSrcResource, LPDIRECT3DTEXTURE9*ppTexture);

设置问题。，DX最多可以设置8层纹理，从而组合得到更细致的图片

SetTexture(0,&_stonewall);

禁用纹理

SetTexture(0,0);

3纹理过滤器

纹理三角形和屏幕三角形大小不适合的时候，通过这项技术，让二者适应

DX提供三种纹理过滤器：

最近点采样：默认情况，速度快，效果差

setsamplerstate(0,D3DSAMP_MAGFILTER,D3DTEXT_POINT);

setsamplerstate(0,D3DSAMP_MINFILTER,D3DTEXT_POINT);

线性纹理过滤器：线性插值，可以分为放大和缩小

SetSamplerState(0,D3DSAMP_MAGFILTER,D3DTEXT_LINEAR);

SetSamplerState(0,D3DSAMP_MINFILTER,D3DTEXT_LINEAR);

各向异性纹理过滤器：多线条采样技术，

setsamplerstate(0,D3DSAMP_MAGFILTER,D3DTEXT_ANISOTROPIC);

setsamplerstate(0,D3DSAMP_MINFILTER,D3DTEXT_ANISOTROPIC);

使用anisotropicfilter时，需要对D3DSAMP_MAXANISOTROPIC水平进行设置

4多级渐进纹理

消除纹理和三角尺寸不一致的问题，创建多级渐进纹理，

多级渐进纹理过滤器：

Device->SetSamplerState(0,D3D_MIPFILTER,flag);

flag:D3DTEXT_NONE：不适用

D3DTEXF_POINT选族最近接的一级纹理，选择后使用指定的纹理过滤器进行处理 D3DTEXF_LINEAR选择最近的两极纹理，用指定纹理过滤器过滤后，再对两极纹理进行线性融合

使用多级渐进纹理之后DX会自动选用合适的尺寸纹理

5寻址模式：处理纹理坐标超过[0,1]范围的问题

有四种扩展模式：

重复寻址模式

Device->SetSamplerState(0,D3DSAMP_ADDRESSU,D3DTADDRESS_WRAP);

Device->SetSamplerState(0,D3DSAMP_ADDRESSV,D3DTADDRESS_WRAP);

边界颜色模式

Device->SetSamplerState(0,D3DSAMP_ADDRESSU,D3DTADDRESS_BORDER);

Device->SetSamplerState(0,D3DSAMP_ADDRESSV,D3DTADDRESS_BORDER);

Device->SetSamplerState(0,D3DSAMP_BORDERCOLOR,0x000000FF);

嵌位寻址模式

Device->SetSamplerState(0,D3DSAMP_ADDRESSU,D3DTADDRESS_CLAMP);

Device->SetSamplerState(0,D3DSAMP_ADDRESSV,D3DTADDRESS_CLAMP);

镜像寻址模式

Device->SetSamplerState(0,D3DSAMP_ADDRESSU,D3DTADDRESS_MIRROR);

Device->SetSamplerState(0,D3DSAMP_ADDRESSV,D3DTADDRESS_MIRROR);

6纹理映射的过程

（1）构建具有纹理坐标的顶点

（2）读取纹理数据

（3）设置缩小放大过滤器，多级渐进纹理过滤器

（4）将纹理与物体关

#include"cube.h"

#include"vertex.h"

//

//Globals

//

IDirect3DDevice9*Device=0;

constintWidth=640;

constintHeight=480;

Cube*Box=0;

IDirect3DTexture9*Tex=0;

//

//FrameworkFunctions

//

boolSetup()

{

//

//Createthecube.

//

Box=newCube(Device);

//

//Setadirectionallight.

//

D3DLIGHT9light;

::ZeroMemory(&light,sizeof(light));

light.Type=D3DLIGHT_DIRECTIONAL;

light.Ambient=D3DXCOLOR(0.1f,0.8f,0.8f,1.0f);

light.Diffuse=D3DXCOLOR(0.9f,1.0f,1.0f,1.0f);

light.Specular=D3DXCOLOR(0.0f,0.2f,1.0f,1.0f);

light.Direction=D3DXVECTOR3(1.0f,0.0f,0.0f);

Device->SetLight(0,&light);

Device->LightEnable(0,true);

Device->SetRenderState(D3DRS_NORMALIZENORMALS,true);

Device->SetRenderState(D3DRS_SPECULARENABLE,true);

//

//Createtexture.

//

D3DXCreateTextureFromFile(

Device,

"crate.jpg",

&Tex);

//

//SetTextureFilterStates.

//

Device->SetSamplerState(0,D3DSAMP_MAGFILTER,D3DTEXF_LINEAR);

Device->SetSamplerState(0,D3DSAMP_MINFILTER,D3DTEXF_LINEAR);

Device->SetSamplerState(0,D3DSAMP_MIPFILTER,D3DTEXF_LINEAR);

//

//Settheprojectionmatrix.

//

D3DXMATRIXproj;

D3DXMatrixPerspectiveFovLH(

&proj,

D3DX_PI*0.5f,//90-degree

(float)Width/(float)Height,

1.0f,

1000.0f);

Device->SetTransform(D3DTS_PROJECTION,&proj);

returntrue;

}

voidCleanup()

{

d3d::Delete<Cube*>(Box);

d3d::Release<IDirect3DTexture9*>(Tex);

}

boolDisplay(floattimeDelta)

{

if(Device)

{

//

//Updatethescene:updatecameraposition.

//

staticfloatangle=(3.0f*D3DX_PI)/2.0f;

staticfloatheight=2.0f;

if(::GetAsyncKeyState(VK_LEFT)&0x8000f)

angle-=0.5f*timeDelta;

if(::GetAsyncKeyState(VK_RIGHT)&0x8000f)

angle+=0.5f*timeDelta;

if(::GetAsyncKeyState(VK_UP)&0x8000f)

height+=5.0f*timeDelta;

if(::GetAsyncKeyState(VK_DOWN)&0x8000f)

height-=5.0f*timeDelta;

D3DXVECTOR3position(cosf(angle)*3.0f,height,sinf(angle)*3.0f);

D3DXVECTOR3target(0.0f,0.0f,0.0f);

D3DXVECTOR3up(0.0f,1.0f,0.0f);

D3DXMATRIXV;

D3DXMatrixLookAtLH(&V,&position,&target,&up);

Device->SetTransform(D3DTS_VIEW,&V);

//

//Drawthescene:

//

Device->Clear(0,0,D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER,0xffffffff,1.0f,0);

Device->BeginScene();

Device->SetMaterial(&d3d::RED_MTRL);

Device->SetTexture(0,Tex);

Box->draw(0,0,0);

Device->EndScene();

Device->Present(0,0,0,0);

}

returntrue;

}

//

//WndProc

//

LRESULTCALLBACKd3d::WndProc(HWNDhwnd,UINTmsg,WPARAMwParam,LPARAMlParam)

{

switch(msg)

{

caseWM_DESTROY:

::PostQuitMessage(0);

break;

caseWM_KEYDOWN:

if(wParam==VK_ESCAPE)

::DestroyWindow(hwnd);

break;

}

return::DefWindowProc(hwnd,msg,wParam,lParam);

}

//

//WinMain

//

intWINAPIWinMain(HINSTANCEhinstance,

HINSTANCEprevInstance,

PSTRcmdLine,

intshowCmd)

{

if(!d3d::InitD3D(hinstance,

Width,Height,true,D3DDEVTYPE_HAL,&Device))

{

::MessageBox(0,"InitD3D()-FAILED",0,0);

return0;

}

if(!Setup())

{

::MessageBox(0,"Setup()-FAILED",0,0);

return0;

}

d3d::EnterMsgLoop(Display);

Cleanup();

Device->Release();

return0;

}