Making enjalot script on OpenCL-OpenGL interoperability

notes_on_starting_with_opencl-opengl-interoperability.md

The code: https://github.com/enjalot/adventures_in_opencl/tree/master/part2/

From the README:

We demonstrate OpenCL and OpenGL context sharing by making a simple particle system.

Build: make a build directory and build the tutorial

 mkdir build
 cd build
 cmake ..
 make

execute the example program

 ./part2.x

On cmake .. had:

CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
...
GLEW_INCLUDE_PATH
...
GLEW_LIBRARY

According to ubuntuforum from 2009 changed GLEW_LIBRARY to GLEW_LIBRARIES in the CMakeLists.txt. The plural ending of the variable was present at all the rest of GET_... variables in TARGET_LINK_LIBRARIES. Similar irregularity was present in GLEW_INCLUDE_PATH -- the rest of INCLUDE_DIRECTORIES had ..._DIR instead of ...PATH on the end. Corrected that. cmake .. worked fine.

make reported missing fatal error: GL/glew.h: No such file or directory. Found them (apt-file search GL/glew.h) in libglew-dev. Installed it. Now make has lots of undefined reference to __glewBindBuffer and alike.

Looking at title "Could NOT find GLEW (missing: GLEW_INCLUDE_DIR GLEW_LIBRARY)" of the issue, and getting that headers were found, but the function definitions were not, changed GLEW_LIBRARIES back to GLEW_LIBRARY in CMakeLists.txt.

Compiled!

Ok, now the it runs.

$ ./part2.x 
Hello, OpenCL
Initialize OpenCL object and context
cl::Platform::get(): CL_SUCCESS
platforms.size(): 3
getDevices: CL_SUCCESS
devices.size(): 1
type: device: 2 CL_DEVICE_TYPE_CPU: 2 
(X) Before defining OS-specific context properties.
(X) Defining OS-specific context properties after Win32 if branch (final else, must be Linux?).
(X) Create command queue.
load the program
kernel size: 408
build program
done building program
Build Status: 0
Build Options:  
Build Log:   
Creating VBO
created VBO, activated, uploaded the data
checked the data is the same as in the input
bound buffer, id = 1
Creating VBO
created VBO, activated, uploaded the data
checked the data is the same as in the input
bound buffer, id = 2
gl interop!
LKAJFA
p_vbo = 1
c_vbo = 2
aaaaaaaaaaaaaa
created OpenCL buffer from GL VBO 1
created OpenCL buffer from GL VBO 2
create OpenCL only arrays
Pushing data to the GPU
push our CPU arrays to the CPU
in popCorn

But no particles in the window.
Does OpenGL run on CPU now?