RTS drag camera style

baxterw3b

Hi guys, im new here, so, hi! :)

i have a problem with the camera RTS, i know that there is a post with pseudo code, but i don't get the point.

I set the initial variables for the camera position and mouse position when the right button is just pressed, and that's ok i think.

The problem is that i calculate then the distance from the mouse to the camera, to keep that offset (when the user press the right button and hold it down), but when i drag, it jump from 0,0 to 3000 something.. lol.. somebody can tell me how can i solve this?

thank you.

baxterw3b

Guys i solve it!, btw thank you! here the code if someone need it.

	if(FlxG.mouse.justPressedRight){

		initialMousePos = new FlxPoint(FlxG.mouse.x, FlxG.mouse.y);
		initialCamPos = new FlxPoint(camera.scroll.x, camera.scroll.y);

		trace("Mouse just pressed: " + initialMousePos);
		trace("Cam just pressed: " + initialCamPos);
	}

	if(FlxG.mouse.pressedRight){

		newMousePos = new FlxPoint(FlxG.mouse.x, FlxG.mouse.y);
		mousePosChanged = newMousePos.subtract(initialMousePos.x, initialMousePos.y);
		camera.scroll.copyFrom(initialCamPos.subtract(mousePosChanged.x, mousePosChanged.y));
	}

baxterw3b

the only thing that im afraid is, im creating new flxPoint every time i press the button, is better to declare it on top and in the update only set it right?

starry-abyss

Yes, or using FlxPoint.get() instead of new(), and then put() when you don't need the point.

baxterw3b

@starry-abyss ok, Thank you mate, i didn't Know about those methods.

baxterw3b

Hi guys, so i'm in love with haxeflixel and how everything works, and thank you for your suggestions, now i have my box selection and my camera that works! the only thing that i found is that setting my bounds if i drag over the map width, height or under 0 x and 0 y, my camera scroll and then snap back to world bounds. i know that i can check the position of the scroll and set it back to 0 or map size, and could work, but because im using the zoom, if i zoom in that case it cut off a bit of the map and don't scroll to the bounds.

so, i have this class

package;

import flixel.FlxCamera;
import flixel.math.FlxPoint;
import flixel.FlxSprite;
import flixel.FlxG;
import flixel.util.FlxColor;
import flixel.math.FlxMath;

class RtsCamera extends FlxCamera
{

	private var initialMousePos:FlxPoint;
	private var initialCamPos:FlxPoint;
	private var newMousePos:FlxPoint;

	public var zoomSpeed:Float = 5;

	public function new(x:Int,y:Int,w:Int,h:Int,z:Float)
	{
		super(x,y,w,h,z);



		initialMousePos = new FlxPoint();
		initialCamPos = new FlxPoint();
		newMousePos = new FlxPoint();
		//setScrollBounds(0,GlobalVariables.WORLD_WIDTH * GlobalVariables.TILE_WIDTH, 0, GlobalVariables.WORLD_HEIGHT * GlobalVariables.TILE_HEIGHT);
		setScrollBoundsRect(0,0,GlobalVariables.WORLD_WIDTH * GlobalVariables.TILE_WIDTH, GlobalVariables.WORLD_HEIGHT * GlobalVariables.TILE_HEIGHT, true);

	}

	override public function update(elapsed:Float):Void
	{
		super.update(elapsed);

		if(FlxG.keys.pressed.ONE){
				// Update camera zoom
				zoom += zoom / 2 * elapsed * zoomSpeed;
		}

		if(FlxG.keys.pressed.TWO){
				// Update camera zoom
				zoom -= zoom / 2 * elapsed * zoomSpeed;
		}


		if(FlxG.mouse.justPressedRight){

			initialMousePos.copyFrom(FlxG.mouse.getWorldPosition());
			initialCamPos.set(camera.scroll.x,camera.scroll.y);

		}

		if(FlxG.mouse.pressedRight){
			newMousePos.copyFrom(FlxG.mouse.getWorldPosition());
			var mousePosChanged = newMousePos.subtract(initialMousePos.x, initialMousePos.y);
			camera.scroll.copyFrom(initialCamPos.subtract(mousePosChanged.x, mousePosChanged.y));
			
		}



	}

	override public function destroy():Void
	{
		super.destroy();
	}
}

how can i lock the camera in a better way to the bounds?

thanks.

baxterw3b

Guys, i solve it, i forgot to call updateScroll()

btw, thank you,

here the code

package;

import flixel.FlxCamera;
import flixel.math.FlxPoint;
import flixel.FlxSprite;
import flixel.FlxG;
import flixel.util.FlxColor;
import flixel.math.FlxMath;

class RtsCamera extends FlxCamera
{

	//Points to handle the drag
	private var initialMousePos:FlxPoint;
	private var initialCamPos:FlxPoint;
	private var newMousePos:FlxPoint;

	//World width in pixel
	private var worldWidth:Int;
	//World height in pixel
	private var worldHeight:Int;
	//Max zoom of the camera;
	private var maxZoom:Int;

	public function new(x:Int,y:Int, startingZoom:Int, maxZoom:Int,mw:Int,mh:Int)
	{
		super(x,y,FlxG.width,FlxG.height,1);

		//Set the starting zoom
		zoom = startingZoom;

		//store size of the world for the bounds
		worldWidth = mw;
		worldHeight = mh;

		//Set the max zoom of the camera
		this.maxZoom = maxZoom;

		//Init points to handle drag
		initialMousePos = new FlxPoint();
		initialCamPos = new FlxPoint();
		newMousePos = new FlxPoint();

		//Set the bounds of the camera
		setScrollBoundsRect(0,0,worldWidth,worldHeight, true);

	}

	override public function update(elapsed:Float):Void
	{
		super.update(elapsed);

		//If right mouse button is pressed the first time
		if(FlxG.mouse.justPressedRight){

			//Set initial mouse and cam position relative to the world
			initialMousePos.copyFrom(FlxG.mouse.getWorldPosition());
			initialCamPos.set(scroll.x,scroll.y);

		}

		//If mouse still pressed
		if(FlxG.mouse.pressedRight){

			//Get the mouse position relative to the world
			newMousePos.copyFrom(FlxG.mouse.getWorldPosition());
			//Find how much the mouse moved and update it's position
			var mousePosChanged = newMousePos.subtract(initialMousePos.x, initialMousePos.y);
			//Change the position of the camera
			scroll.copyFrom(initialCamPos.subtract(mousePosChanged.x, mousePosChanged.y));
			//Update the initial mouse position to the new position relative to the world
			initialMousePos.copyFrom(FlxG.mouse.getWorldPosition());

		}

		//If i'm scrolling
		if (FlxG.mouse.wheel != 0)
		{
		    //zoom in or out
		    zoom += (FlxG.mouse.wheel / 10);
		}

		//Clamp the zoom
		zoom = clamp(zoom, 1, maxZoom);

		//Update the camera to clamp it on world bounds based on the zoom
		updateScroll();

	}

	//function to destroy the object
	override public function destroy():Void
	{
		super.destroy();
	}

	//function to clamp a value
	private function clamp(value:Float, min:Float, max:Float):Float
	{
		if(value < min) return min;
		if(value > max) return max;
		return value;
	}


}

RTS drag camera style browsing