source: 2013/30/DenisZ/CastleMaster/CastleMaster/CastleMaster/Graphics/AnimationHelper.cs @ 4535

namespace CastleMaster.Graphics
{
    public class AnimationHelper
    {
        private int currentFrame, minFrame, maxFrame, currentTicks, ticksPerFrame;
        private bool isRunning = false, runOnce;

        public AnimationHelper(int ticksPerFrame, int maxFrame, bool runOnce = false, int minFrame = 0, int currentFrame = 0)
        {
            this.ticksPerFrame = ticksPerFrame;
            this.maxFrame = maxFrame;
            this.minFrame = minFrame;
            this.currentFrame = currentFrame < minFrame ? minFrame : currentFrame;
            this.runOnce = runOnce;
            currentTicks = 0;
        }

        public int CurrentFrame { get { return currentFrame; } }

        public AnimationHelper Start()
        {
            if (!isRunning)
                isRunning = true;
            return this;
        }

        public void Stop()
        {
            isRunning = false;
        }

        public void Reset()
        {
            currentFrame = minFrame;
            currentTicks = 0;
        }

        public void Restart()
        {
            isRunning = true;
            currentFrame = minFrame;
            currentTicks = 0;
        }

        public void UpdateStep()
        {
            currentTicks++;

            if (currentTicks > ticksPerFrame)
            {
                currentFrame++;
                if (currentFrame > maxFrame)
                {
                    if (runOnce) Stop();
                    else currentFrame = 0;
                }

                currentTicks = 0;
            }
        }
    }
}