Create & apply dynamic texutre（创建并使用动态创建的纹理）

#include "OgreHardwarePixelBuffer.h"
// Create the texture
TexturePtr texture = TextureManager::getSingleton().createManual(
"DynamicTexture", // name
ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,
TEX_TYPE_2D,      // type
256, 256,         // width & height
0,                // number of mipmaps
PF_FLOAT32_GR,    // pixel format  （双通道DDS浮点纹理）
TU_DEFAULT);      // usage; should be TU_DYNAMIC_WRITE_ONLY_DISCARDABLE for
// textures updated very often (e.g. each frame)

// Get the pixel buffer
HardwarePixelBufferSharedPtr pixelBuffer = texture->getBuffer();

// Lock the pixel buffer and get a pixel box
pixelBuffer->lock(HardwareBuffer::HBL_NORMAL); // for best performance use HBL_DISCARD!
const PixelBox& pixelBox = pixelBuffer->getCurrentLock();

float* pDest = static_cast<float*>(pixelBox.data);

// Fill in some pixel data. This will give a semi-transparent blue,
// but this is of course dependent on the chosen pixel format.
for (size_t j = 0; j < 256; j++)
for(size_t i = 0; i < 256; i++)
{
*pDest++ = *(gChannel++);  // gChannel:G通道数据数组指针
*pDest++ = *(rChannel++);  // rChannel:R通道数据数组指针
}

// Unlock the pixel buffer
pixelBuffer->unlock();

void SaveImage(TexturePtr TextureToSave, String filename)
{
HardwarePixelBufferSharedPtr readbuffer;
readbuffer = TextureToSave->getBuffer(0, 0);
readbuffer->lock(HardwareBuffer::HBL_NORMAL );
const PixelBox &readrefpb = readbuffer->getCurrentLock();
uchar *readrefdata = static_cast<uchar*>(readrefpb.data);

Image img;
img = img.loadDynamicImage (readrefdata, TextureToSave->getWidth(),
TextureToSave->getHeight(), TextureToSave->getFormat());
img.save(filename);   // 此处抛出异常：DDS encoding not supported！

readbuffer->unlock();
}

但是，程序执行到img.save(filename)的时候出现异常，提示“不支持DDS编码”。Ogre Forum上面搜到这个贴：

https://www.ogre3d.org/forums/viewtopic.php?f=5&t=38606&start=0 里面有人说：

“Ogre's DDS codec does not support encoding DDS, only decoding.”

查看ogreddscodec.cpp中的异常抛出函数确实是这样的：

void DDSCodec::codeToFile(MemoryDataStreamPtr& input,
const String& outFileName, Codec::CodecDataPtr& pData) const
{
OGRE_EXCEPT(Exception::ERR_NOT_IMPLEMENTED,
"DDS encoding not supported",
"DDSCodec::codeToFile" ) ;
}

MaterialPtr material = MaterialManager::getSingleton().getByName("Test");
material.getPointer()->getTechnique(0)->getPass(0)->getTextureUnitState("DynamicTextureTU")->setTextureName("DynamicTextureTU");

材质Test的定义：

material Test
{
technique
{
pass
{
lighting off
scene_blend alpha_blend
depth_write off
texture_unit DynamicTextureTU
{ // blank
}

}
}

}