wbuffers(readbufferFormat, drawbuffersFormatMask, filter) {
    debug("");
    debug("The filter is: " + wtu.glEnumToString(gl, filter));
    debug("Read buffer format is: " + wtu.glEnumToString(gl, readbufferFormat));
    var drawbuffersFormat = "\0";
    if (drawbuffersFormatMask & linearMask) {
        drawbuffersFormat += " linear ";
    }
    if (drawbuffersFormatMask & srgbMask) {
        drawbuffersFormat += " srgb ";
    }
    debug("The test have multiple draw buffers, the images are: " + drawbuffe