Mat and int are incompatible?
Hi I do not understand it gives you that error, since my trouble compiling me, on the other hand the operator "&lt;&lt;" is useful to be able to initialize the array, thus "0, 0, width, width" correspond to the first row, "0, height, height, 0" correspond to the second row and "1, 1, 1, 1" correspond to the third row.