better document map_ranges, optimize map_bound_ranges

diff --git a/qcsrc/lib/math.qh b/qcsrc/lib/math.qh
index 3e77b369fdf37110c332d948c71935c2539a28eb..f20b1c66e5bf120be7748737dabe8b9e8dec9f88 100644 (file)
--- a/qcsrc/lib/math.qh
+++ b/qcsrc/lib/math.qh
@@ -326,7 +326,9 @@ vector solve_quadratic(float a, float b, float c)
 /// Maps values between the src and dest range: src_min to dest_min, src_max to dest_max, values between them
 /// to the curresponding values between and extrapolates for values outside the range.
 ///
-/// Max can be lower than min if you want to invert the range, values can be negative.
+/// src_min and src_max must not be the same or division by zero accurs.
+///
+/// dest_max can be smaller than dest_min if you want the resulting range to be inverted, all values can be negative.
 ERASEABLE
 float map_ranges(float value, float src_min, float src_max, float dest_min, float dest_max) {
        float src_diff = src_max - src_min;
@@ -338,6 +340,7 @@ float map_ranges(float value, float src_min, float src_max, float dest_min, floa
 /// Same as `map_ranges` except that values outside the source range are clamped to min or max.
 ERASEABLE
 float map_bound_ranges(float value, float src_min, float src_max, float dest_min, float dest_max) {
-       value = bound(src_min, value, src_max);
+       if (value <= src_min) return dest_min;
+       if (value >= src_max) return dest_max;
        return map_ranges(value, src_min, src_max, dest_min, dest_max);
 }