简明教程_WJ的Direct3D简明教程3：CreateTexturewithUserdefinedImageData

转载请注明&＃xff1a;来自
http://blog.csdn.net/skyman_2001

Usually we use D3DXCreateTextureFromFile() function to create a texture from external file, but how do we create it with user-defined image data? The way is as follows:


1. Create an empty texture:

LPDIRECT3DTEXTURE9 pTexture &＃61; NULL;

LPDIRECT3DSURFACE9 pRenderSurface &＃61; NULL;



D3DXCreateTexture(pDevice,

256, // width

256, // height

0, // number of mip levels(0 - a complete mipmap chain is created)

0, // usage

D3DFMT_A8R8G8B8, // format

D3DPOOL_MANAGED, // pool(cannot be D3DPOOL_DEFAULT here)

&pTexture);


2. Retrieve this texture surface level:

pTexture->GetSurfaceLevel(0, &pRenderSurface);

D3DSURFACE_DESC surfaceDesc;

pRenderSurface->GetDesc(&surfaceDesc);


3. Lock a rectangle on the surface:

D3DLOCKED_RECT lockedRect;

pRenderSurface->LockRect(&lockedRect, 0, 0); // entire surface




NOTE: This method cannot retrieve data from a surface that is is contained by a texture resource created with
D3DUSAGE_RENDERTARGET because such a texture must be assigned to D3DPOOL_DEFAULT memory and is therefore not lockable. In this case, use instead
GetRenderTargetData to copy texture data from device memory to system memory.


4. Retrieve and modify the surface&＃39;s data :

DWORD* imageData &＃61; (DWORD*)lockedRect.pBits;

for(int i &＃61; 0; i
{

for(int j &＃61; 0; j
{

int index &＃61; i * (lockedRect.Pitch / 4) &＃43; j; // because pitch is in bytes, and 4 bytes per DWORD

imageData[index] &＃61; 0xffffff00;

}

}


5. Unlock the rectangle:
pRenderSurface->UnlockRect();