Directx11 loading texture - c++

Question

What's alternative to D3DXCreateTextureFromFileInMemory and D3DXCreateTextureFromFileEx in d3d11? Simply how can I load image to texture buffer (looks like it ID3D10Texture2D data type) to be able to render it?

Answer 1

That's kind of a broad question, but hopefully I can help point you in the right direction.
At the highest level, "loading" a texture involves the following steps:
Place image data in some form into memory (either loading from a file, generating algorithmically, etc).
Convert the image data into the raw form required by the texture. This will be predicated on the format texture you require. For example, most color (albedo) textures will be in the DXGI_FORMAT_R8G8B8A8_UNORM_SRGB format. This step may involve decompression of a source image file (e.g. if it's JPEG or PNG), and possibly some form of conversation if the formats take different data types, etc.
(Optional) generate the mip chain for the texture. Generally, having a full mip chain is a good idea for visual and performance reasons.
Copy the raw pixel data into the texture. Format conversion could be done during this step (it really depends on the implementation).
For the conversion part, there are plenty of libraries that will load and convert image files to raw pixel data. One such is the Windows Imaging Component library (WIC). There are others out there, too - a google search will yield lots of results.
For MIP generation, you can do this yourself, or some of the third party imaging libraries will do this for you. D3DX will also generate mips. Another option is to have D3D generate them for you (not ideal, but can work as a stop-gap) via the ID3D11DeviceContext::GenerateMips call.
Top copy raw pixel data into the texture, assuming it's static (unchanging, or "immutable") data, you should create your texture like so:
D3D11_TEXTURE2D_DESC tdesc;
// ...
// Fill out width, height, mip levels, format, etc...
// ...
tdesc.Usage = D3D11_USAGE_IMMUTABLE;
tdesc.BindFlags = D3D11_BIND_SHADER_RESOURCE; // Add D3D11_BIND_RENDER_TARGET if you want to go
// with the auto-generate mips route.
tdesc.CPUAccessFlags = 0;
tdesc.MiscFlags = 0; // or D3D11_RESOURCE_MISC_GENERATE_MIPS for auto-mip gen.
D3D11_SUBRESOURCE_DATA srd; // (or an array of these if you have more than one mip level)
srd.pSysMem = pointer_to_raw_pixel_data; // This data should be in raw pixel format
srd.SysMemPitch = width_of_row_in_bytes; // Sometimes pixel rows may be padded so this might not be as simple as width * pixel_size_in_bytes.
srd.SysMemSlicePitch = 0;
ID3D11Texture2D * texture;
pDevice->CreateTexture2D(&tdesc, &srd, &texture);
This will create the texture and populate it with your pixel data in one go. You can also create the texture with the D3D11_USAGE_DEFAULT usage flag, and use the ID3D11DeviceContext::Map/Unmap calls to do this after creation (this is useful if you'll be changing the texture content occasionally).
This is a kinda rough overview of the basics - there's a ton of stuff out there on the web going into the dirty details of how all this stuff works and best practices etc. I think the best thing I can recommend is find some sample code and experiment with it.