# JSDoc: Source: controls/ViewportControls.js

# Source: controls/ViewportControls.js

    "use strict";

    import {Viewport} from "../Viewport.js";
    import {Pointer} from "../input/Pointer.js";
    import {Vector2} from "../math/Vector2.js";

    /**
     * Viewport controls are used to allow the user to control the viewport.
     *
     * @class
     * @param {Viewport} viewport
     */
    function ViewportControls(viewport)
    {
    	/**
    	 * Viewport being controlled by this object.
    	 */
    	this.viewport = viewport;

    	/**
    	 * Button used to drag and viewport around.
    	 *
    	 * On touch enabled devices the touch event is represented as a LEFT button.
    	 */
    	this.dragButton = Pointer.RIGHT;

    	/**
    	 * Is set to true allow the viewport to be scalled.
    	 *
    	 * Scaling is performed using the pointer scroll.
    	 */
    	this.allowScale = true;

    	/**
    	 * Flag to indicate if the viewport should move when scalling.
    	 *
    	 * For some application its easier to focus the target if the viewport moves to the pointer location while scalling.
    	 */
    	this.moveOnScale = false;

    	/**
    	 * If true allows the viewport to be rotated.
    	 *
    	 * Rotation is performed by holding the RIGHT and LEFT pointer buttons and rotating around the initial point.
    	 */
    	this.allowRotation = true;

    	/**
    	 * Value of the initial point of rotation if the viewport is being rotated.
    	 *
    	 * Is set to null when the viewport is not being rotated.
    	 */
    	this.rotationPoint = null;

    	/**
    	 * Initial rotation of the viewport.
    	 */
    	this.rotationInitial = 0;
    }

    /**
     * Update the viewport controls using the pointer object.
     *
     * Should be called every frame before rendering.
     *
     * @param {Pointer} pointer
     */
    ViewportControls.prototype.update = function(pointer)
    {
    	// Scale
    	if(this.allowScale && pointer.wheel !== 0)
    	{
    		var scale = pointer.wheel * 1e-3 * this.viewport.scale;

    		this.viewport.scale -= scale;
    		this.viewport.matrixNeedsUpdate = true;

    		// Move on scale
    		if(this.moveOnScale && pointer.canvas !== null)
    		{
    			this.viewport.updateMatrix();

    			var pointerWorld = this.viewport.inverseMatrix.transformPoint(pointer.position);

    			var centerWorld = new Vector2(pointer.canvas.width / 2.0, pointer.canvas.height / 2.0);
    			centerWorld = this.viewport.inverseMatrix.transformPoint(centerWorld);

    			var delta = pointerWorld.clone();
    			delta.sub(centerWorld);
    			delta.multiplyScalar(0.1);

    			this.viewport.position.sub(delta);
    			this.viewport.matrixNeedsUpdate = true;
    		}
    	}

    	// Rotation
    	if(this.allowRotation && pointer.buttonPressed(Pointer.RIGHT) && pointer.buttonPressed(Pointer.LEFT))
    	{
    		// Rotation pivot
    		if(this.rotationPoint === null)
    		{
    			this.rotationPoint = pointer.position.clone();
    			this.rotationInitial = this.viewport.rotation;
    		}
    		else
    		{
    			var pointer = pointer.position.clone();
    			pointer.sub(this.rotationPoint);
    			this.viewport.rotation = this.rotationInitial + pointer.angle();
    			this.viewport.matrixNeedsUpdate = true;
    		}
    	}
    	// Drag
    	else
    	{
    		this.rotationPoint = null;

    		if(pointer.buttonPressed(this.dragButton))
    		{
    			this.viewport.position.x += pointer.delta.x;
    			this.viewport.position.y += pointer.delta.y;
    			this.viewport.matrixNeedsUpdate = true;
    		}
    	}
    };

    export {ViewportControls};