Quote Originally Posted by Michele Bosi View Post

glVertexAttribPointer(MyMatID+0, ....); // column 0
glVertexAttribPointer(MyMatID+1, ....); // column 1
glVertexAttribPointer(MyMatID+2, ....); // column 2
glVertexAttribPointer(MyMatID+3, ....); // column 3
Would you mind sharing how you're setting up your vertex attribute pointers? I'm attempting and this isn't working for me. For example, I'm using:

glVertexAttribPointer(MyMatID+0, 4, GL_FLOAT, GL_FALSE, 0, NULL);
glVertexAttribPointer(MyMatID+1, 4, GL_FLOAT, GL_FALSE, 0, NULL);
glVertexAttribPointer(MyMatID+2, 4, GL_FLOAT, GL_FALSE, 0, NULL);
glVertexAttribPointer(MyMatID+3, 4, GL_FLOAT, GL_FALSE, 0, NULL);

but I'm not sure whether the stride and offset are correct.

Also, do those 4 attribute locations represent the rows or the columns of the matrix?