img_filter_2d_nearest and the other image filter functions access the args->offset property of the img_filter structure which is a pointer without checking if the value is actually defined. img_filter_2d_ewa(...) creates a local copy of img_filter, but it never initializes the offset property. When that local copy of img_filter is passed into min_filter(sp_sview, sp_samp, &args, &rgba_temp[0][jj]), an access violation occurs when the offset property is attempted to be read.