9、osg的texture转换为虚幻引擎的UTexture2D

从osg::Texture中读取纹理图片，并动态转换为虚幻引擎的UTexture2D，不过这段代码只能转换图片格式为R8G8B8A8的纹理图片，其他格式请根据实际情况进行修改

UTexture2D* ConvertOsgTexture2UeTexture2D(osg::Texture* texture) {
	if (texture)
	{
		const unsigned int numImages = texture->getNumImages();
		if (numImages != 0) {
			for (unsigned int j = 0; j < numImages; j++) {
				osg::ref_ptr<osg::Image> img = texture->getImage(j);
				//osgb的纹理坐标的y轴和虚幻引擎的纹理坐标的y轴是相反的
				img->flipVertical();
				const int imgWidth = img->s();
				const int imgHeight = img->t();

				UTexture2D* ueTexture2D = NewObject<UTexture2D>();
				ueTexture2D->AddToRoot();
				FTexturePlatformData* platformData = new FTexturePlatformData();
				ueTexture2D->SetPlatformData(platformData);
				ueTexture2D->PlatformData->SizeX = imgWidth;
				ueTexture2D->PlatformData->SizeY = imgHeight;
				ueTexture2D->PlatformData->SetNumSlices(1);
				ueTexture2D->PlatformData->PixelFormat = EPixelFormat::PF_R8G8B8A8;
				//填充texture,创建一个像素数组，然后为每个数组定义颜色。数组大小为width*height*每个像素的字节
				const int32 numBlocksX = imgWidth / GPixelFormats[EPixelFormat::PF_R8G8B8A8].BlockSizeX;
				const int32 numBlocksY = imgHeight / GPixelFormats[EPixelFormat::PF_R8G8B8A8].BlockSizeY;
				const int32 size = numBlocksX * numBlocksY * GPixelFormats[EPixelFormat::PF_R8G8B8A8].BlockBytes;

				//接下来，把颜色数组输入到纹理中去
				FTexture2DMipMap* mip = new FTexture2DMipMap();
				mip->SizeX = imgWidth;
				mip->SizeY = imgHeight;
				mip->BulkData.Lock(LOCK_READ_WRITE);
				uint8* pTextureData = static_cast<uint8*>(mip->BulkData.Realloc(size));
				memset(pTextureData, 255, size);
				for (int k = 0; k < imgWidth * imgHeight; k++)
				{
					FMemory::Memcpy(&pTextureData[k * 4], &img->data()[k * 3], 3 * sizeof(uint8));
				}
				mip->BulkData.Unlock();
				ueTexture2D->PlatformData->Mips.Add(mip);
				//保存texture
				ueTexture2D->UpdateResource();

				return ueTexture2D;
			}
		}
	}
	return nullptr;
}