select_relative
Returns an argument in a position relative to a given value. This is useful for sequentially selecting values from a list based on a current value.
// Move forwards {+1} through a list of colors
color = select_relative(color, +1, c_red, c_orange, c_yellow, c_green, c_blue);In the above example, if the current value of color is c_orange, then its new value
would be set to the next value in the list, c_yellow.
// Or move backwards {-1} through a list of colors
color = select_relative(color, -1, c_red, c_orange, c_yellow, c_green, c_blue);If a relative position is beyond the range of given choices, the position is clamped
to be within range. In the second example, if the current value of color is c_red,
then it would keep its value because c_red is the first value in the list.
If the current value isn't among the choices, the returned value is undefined.
- select_relative(current, delta, choice0, choice1, choice2, ...)
- Returns an argument in a position relative to a given value.
COPY/// @func select_relative(current, delta, choice0, choice1, choice2, ...)
///
/// @desc Returns an argument in a position relative to a given value.
/// If a relative position is beyond the range of given choices,
/// the position is clamped to be within range. If current value
/// isn't among the choices, the return value is undefined.
///
/// eg. select_relative("Name", -2, "Hello", "Doctor", "Name") == "Hello"
/// select_relative("Doctor", 2, "Hello", "Doctor", "Name") == "Name"
///
/// @param {any*} current value matching a given choice
/// @param {real} delta relative position of desired choice
/// @param {any*} choiceN value to return, if selected
///
/// @return {any*} selected choice
///
/// GMLscripts.com/license
function select_relative()
{
var current = argument[0];
var delta = argument[1];
var size = argument_count - 2;
var choices = ds_list_create();
var result = undefined;
for (var i = 2; i < argument_count; i++) ds_list_add(choices, argument[i]);
i = ds_list_find_index(choices, current);
if (i >= 0) {
i = clamp(i + delta, 0, size - 1);
var result = ds_list_find_value(choices, i);
}
ds_list_destroy(choices);
return result;
}
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