示例#1
0
        public virtual void UpdateVelocity(CCPoint point)
        {
            // Calculate distance and angle from the center.
            float dx = point.X - PositionX;
            float dy = point.Y - PositionY;

            dycache = dy;
            float dSq = dx * dx + dy * dy;

            if (dSq <= DeadRadiusSq)
            {
                Velocity      = CCPoint.Zero;
                Degrees       = 0.0f;
                StickPosition = Center;
                return;
            }

            float angle = (float)Math.Atan2(dy, dx); // in radians

            if (angle < 0)
            {
                angle += CCMathHelper.TwoPi;
            }

            float cosAngle;
            float sinAngle;

            if (isDPad)
            {
                float anglePerSector = 360.0f / CCMathHelper.ToRadians(NumberOfDirections); //  NumberOfDirections * ((float)Math.PI / 180.0f);
                angle = (float)Math.Round(angle / anglePerSector) * anglePerSector;
            }

            cosAngle = CCMathHelper.Cos(angle);
            sinAngle = CCMathHelper.Sin(angle);

            // NOTE: Velocity goes from -1.0 to 1.0.
            if (dSq > JoystickRadiusSq || isDPad)
            {
                dx = cosAngle * joystickRadius;
                dy = sinAngle * joystickRadius;
            }

            Velocity = new CCPoint(dx / joystickRadius, dy / joystickRadius);
            Degrees  = CCMathHelper.ToDegrees(angle);

            // Update the thumb's position
            var newLoc = new CCPoint(dx + ContentSize.Width / 2, dy + ContentSize.Height / 2);

            StickPosition = newLoc;
        }