CMAKE for a build a simple framework

I have my mind crashing with cmake. After this answer I have tried to make a simple example and put it in github because there are a lot of file inside directories and could be boring copy everything here.

What I'd like to do is to build a simple frameworks for handling my qt/opencv/opengl experiments. What I like to have is a repository with those directories:

 root*
   |-apps
   |---test1*
   |
   |-build
   |-cmake*
   |
   |-modules
   |---foo*

(The * signed directory are the ones with some cmake files like CmakeLists.txt or FindXXModule.cmake)

In modules i can write the modules (for example a module for face recognition, a module for draw a red cube in opengl, a module that contains my personal qt widget extension).

Than I need an easy way for create an application and link some modules on it. For that I thought to create a cmake directory where to put the FindXXModule.cmake and in the apps just say: find_package(XXModule).

Note that for now I don't care about installing this repository and the tree structure must be this one (so if I am in a apps/test2 I know I can refer to the cmake directory as ../../cmake or the module directory is ../../modules)

I have wrote a little example with the app named test1 that uses the module foo and i put it in a github repository.

For now I can compile the application test1 with cmake calling cmake path_to_test1_CmakeLists.txt and I am happy about that. But if I try to launch cmake path_to_root_CmakeLists.txt it does not work because the file Findfoo.cmake is read two time (and i did't be able to use some if for not reading it twice).

Then, if i run the test1 cmake a foo directory with cmake cache etc are created in root/cmake and I don't want it. I want all file cmake has to generate are in root/build directory.

So, those are my 2 question:

How create a CmakeLists.txt that can build all the apps and all the future test i will write in the modules directory
How avoid that launching cmake of a single app will create files in the cmake directory.

Sorry if my english and my idea of how cmake works are not good.. i hope it is clear.

EDIT:

One more thing. In Findfoo.cmake I have a bad hack: for adding the real CMakeLists.txt inside a modules/foo when I call the cmake from test1 I have to add a subdirectory that is not in the tree.. Maybe this kind of hack could be deleted reviewing the enteire structure..

As you say you want to put the whole directory structure into source control. This means these folder structure is same on every location where you do a checkout. So why creating the Findfoo.cmake if you have a relative path the the foo directory?

I suggest to put a CMakelists.txt file in to root that adds all subdirectories. To reduce confusion between files generated by CMake and original files, you should create a folder called ./build (or even ../build) and run CMake in that directory with the root directory as first argument. This creates all CMake generated files in the ./build directory and gives you the possibility to clean it up easily. This way of working is called out-of-source build and its highly recommended to use cmake in this way. See this question for an example.