With this function you can multiply two matrix arrays together to create a new transform matrix. The function will return the new matrix index which should be stored in a variable for future use.NOTE: You can't use a matrix constant as an argument with this function, so if you wish to multiply the (for example) view matrix with a custom matrix that you have built, you must first call matrix_get(type) and assign the view matrix values to an array variable, then multiply it by your custom matrix, and then set the chosen matrix (view, projection or world).
Argument Description matrix1 The first matrix index to use. matrix2 The second matrix index to use.
var v_matrix = matrix_get(matrix_view);
var new_matrix = matrix_multiply(v_matrix, my_matrix);
The above code will get the current view matrix, then multiply that with a custom matrix and then use the resulting matrix index to set the view matrix again.