function bloom(threshold, horizontal, vertical, boost, samplerNum, taps, reps) {
    return new BloomLoop(expr_1.wrapInValue(threshold), expr_1.wrapInValue(horizontal), expr_1.wrapInValue(vertical), expr_1.wrapInValue(boost), samplerNum, taps, reps);
}
creates a bloom loop
@param threshold values below this brightness don't get blurred (0.4 is
about reasonable, which is also the default)
@param horizontal how much to blur vertically (defaults to 1 pixel)
@param vertical how much to blur horizontally (defaults to 1 pixel)
@param taps how many taps for the blur (defaults to 9)
@param reps how many times to loop the blur (defaults to 3)