function Horizon(canvas, spritePos, dimensions, gapCoefficient) {
        this.canvas = canvas;
        this.canvasCtx = this.canvas.getContext('2d');
        this.config = Horizon.config;
        this.dimensions = dimensions;
        this.gapCoefficient = gapCoefficient;
        this.obstacles = [];
        this.obstacleHistory = [];
        this.horizonOffsets = [0, 0];
        this.cloudFrequency = this.config.CLOUD_FREQUENCY;
        this.spritePos = spritePos;
        this.nightMode = null;

        // Cloud
        this.clouds = [];
        this.cloudSpeed = this.config.BG_CLOUD_SPEED;

        // Horizon
        this.horizonLine = null;
        this.init();
    }
***************************************************************************

    /**
Horizon background class.
@param {HTMLCanvasElement} canvas
@param {Object} spritePos Sprite positioning.
@param {Object} dimensions Canvas dimensions.
@param {number} gapCoefficient
@constructor