recrownedgtk/RecrownedAthenaeum/Render/ScissorBox.cs

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace RecrownedAthenaeum.Render
{
    /// <summary>
    /// Box that crops off anything outside of the bounds.
    /// </summary>
    public class ScissorBox
    {

        ConsistentSpriteBatch spriteBatch;
        Rectangle originalScissor;
        RasterizerState originalRasterizerState;

        RasterizerState scissorRasterizerState;

        /// <summary>
        /// Used to crop off anything that doesn't fit into the defined space.
        /// </summary>
        public ScissorBox()
        {
            scissorRasterizerState = new RasterizerState();
            scissorRasterizerState.ScissorTestEnable = true;
        }

        /// <summary>
        /// Starts spritebatch with scissoring enabled.
        /// </summary>
        /// <param name="rectangle"></param>
        /// <param name="spriteBatch"></param>
        public void Begin(Rectangle rectangle, ConsistentSpriteBatch spriteBatch)
        {
            this.spriteBatch = spriteBatch;
            originalRasterizerState = spriteBatch.RasterizerState;
            spriteBatch.Begin(rasterizerState: scissorRasterizerState);

            originalScissor = spriteBatch.GraphicsDevice.ScissorRectangle;
            spriteBatch.GraphicsDevice.ScissorRectangle = rectangle;
        }

        /// <summary>
        /// Ends the scissoring and spritebatch.
        /// </summary>
        public void End()
        {
            spriteBatch.GraphicsDevice.ScissorRectangle = originalScissor;
            spriteBatch.RasterizerState = originalRasterizerState;
            spriteBatch.End();
        }
    }
}