Gathering Data v1 Part 1

First, lets decide on what we need.

We need:

• a way to gather which nearby objects
• a way to gather the object’s location in the game world

• a way to translate that location into on-screen coords
• a way to check whether object is on screen

(Below will be covered in Part 2)

• a way to get an object’s bounding box
• a way to get the extreme coordinates of the bounding box

• a way to take a screenshot
• a way to tag the locations gathered, to the screenshot taken

Gathering nearby objects and its location

We can make use of the function nearTargets, where it returns an array of objects within a user-defined range (in the code below, DetectionRange_GlobalVariable is the variable for this range). The following code will write all the nearby targets as a hint. Part of the returned array is the object location in the game world. This will be useful later.

HintNearbyTargets = {
    private _outputstr = "";
    _outputstr = _outputstr + str diag_tickTime;
    {
        _outputstr = _outputstr + "\n";
        _outputstr = _outputstr + "\n" + str (_x select 1);
        _outputstr = _outputstr + "\nObj pos: " + str (_x select 0);
        _ifonscreen = [(_x select 4)] call CheckOnScreen; // this will be discussed in the following section
        _outputstr = _outputstr + "\nOn screen: " + str (_ifonscreen);
        [(_x select 4), (_x select 0)] call DrawBB; // this will be discussed in another section
    } forEach (cameraOn nearTargets DetectionRange_GlobalVariable); // distance in meters
    hint _outputstr;
};

Convert world position to screen position, and check whether object is on screen

Arma 3 provides a function, worldToScreen, which converts a world position to screen position. The user just needs to pass in the world location.

Even if the object is not on screen, Arma will sometime return a negative value. As such, we have to manually check whether the object exceeds the width of the screen.

The following code takes in an object, and returns true if the object is on screen, else returns false.

// Check if _obj is on screen, returns true or false
CheckOnScreen = {
	params ["_obj"];
	private _retcoords = worldToScreen (position _obj); // returns [x, y]
	// if no return, means confirmed not on screen.

	if (count _retcoords isEqualTo 0) then {
		false;
	} else {
		x = safeZoneX;
		y = safeZoneY;
		w = safeZoneW;
		h = safeZoneH;
		if (((x < (_retcoords select 0)) &&
		((_retcoords select 0) < w)) &&
		((y < (_retcoords select 1)) &&
		((_retcoords select 1) < h)))
		then{
			true;
		} else {
			false;
		}
	};
};