Passing data to external libs

If you ever come across a situation where you need to pass data from PyGLM's data types to another library that uses external C code, you should be able to accomplish your goal doing the following:

It doesn't matter which kind of PyGLM type you have, but let's pretend you have a 4x4 matrix that you need to pass to PyOpenGL.

# a very important identity matrix
m      = glm.mat4()

# a ctypes pointer to m's data
ptr    = glm.value_ptr(m) 

# size of m's data in bytes (here 4 * 4 * 4 = 64 bytes)
nbytes = glm.sizeof(m)

glBufferData(GL_UNIFORM_BUFFER, nbytes, ptr, GL_STATIC_DRAW)

This also works for any vector, quaternion or array type.

You can take a shortcut for arrays though:

arr = glm.array(glm.mat4(1), glm.mat4(2), glm.mat4(3))

glBufferData(GL_UNIFORM_BUFFER, arr.nbytes, arr.ptr, GL_STATIC_DRAW)