Why glm::vec3 is not ordered like a floating array [closed] - c++

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I'm learning openGL from this website https://learnopengl.com
To draw a simple triangle, the first example provided by this website is using a float array:
float triangle[] = {
-0.5f, -0.5f, 0.0f, // left
0.5f, -0.5f, 0.0f, // right
0.0f, 0.5f, 0.0f // top
};
Of course it work well. But beside this example I have tried to use a basic structur carrying glm::vec3 as follow :
struct Position {
glm::vec3 pos;
};
Then to store the same data as the float array I just did a simple array of Position as follow :
Position leTriangle[3];
leTriangle[0].pos = glm::vec3(-0.5f, -0.5f, 0.0f);
leTriangle[1].pos = glm::vec3(0.5f, -0.5f, 0.0f);
leTriangle[2].pos = glm::vec3(0.0f, 0.5f, 0.0f);
(Of course all this was just to test if it could work)
Then after having sent my array of Position to the GPU using glBufferData and glVertexAttribPointer the triangle wasn't appearing anymore. So, juste to see if the array I sent where similar to the exemple floating array, I did this :
float* test = (float*)&leTriangle;
for(int e = 0; e < ((12/4) * 3); e++,test++){
std::cout << *test << std::endl;
}
And instead of printing the same floating array, it print this :
0.0f,-0.5f,-0.5f,// left
0.0f,-0.5f,0.5f, // right
0.0f,0.5f,0.0f // top
X and Z value has been inverted. So I guessed the order of the GLM data is not what I thought.
Can someone explain me why data in GLM are ordered this way? Should I respect this order or maybe I should try to reverse it? Maybe it's not important, is it something I should have in mind when placing 3D object?

Answer 1

Data in the glm::vec3 struct is ordered correctly. You could easily verify this by checking up memory, pointed by your test variable:
You are getting strange results, because something in your test is wrong, you are clearly reading glm::vec3 fields backward. Code in your question does not exhibit this behavior. Perhaps you should check how you assign your data.