LunaLightXMG/Game1.cs

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using System;

namespace LunaLightXMG
{
    public class Game1 : Game
    {
        private GraphicsDeviceManager graphics;
        private SpriteBatch spriteBatch;

        // Test Render Target
        private RenderTarget2D renderTarget;
        private Rectangle renderDestination;
        bool resizing;

        // Test sprites
        Texture2D sprRo;
        Texture2D sprCave1_background;
        Texture2D sprCave1_foreground;
        Texture2D sprCave1_walls;

        // Native retro scale
        private int retroWidth = 320;
        private int retroHeight = 180;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            IsMouseVisible = true;

            Window.ClientSizeChanged += OnClientSizeChanged; // Jensen can implement
            Window.AllowUserResizing = true;
            IsMouseVisible = true;
        }

        private void OnClientSizeChanged(object sender, EventArgs eventArgs)
        {
            if (!resizing && Window.ClientBounds.Width > 0 && Window.ClientBounds.Height > 0)
            {
                resizing = true;
                CalculateRenderDestination();
                resizing = false;
            }
        }

        protected override void Initialize()
        {
            // Set initial window size
            graphics.PreferredBackBufferWidth = 1920;
            graphics.PreferredBackBufferHeight = 1080;
            graphics.ApplyChanges();

            base.Initialize();
            CalculateRenderDestination(); // Jensen can implement 
        }

        private void CalculateRenderDestination()
        {
            Point size = GraphicsDevice.Viewport.Bounds.Size;

            float scaleX = (float)size.X / renderTarget.Width;
            float scaleY = (float)size.Y / renderTarget.Height;
            float scale = Math.Min(scaleX, scaleY);

            renderDestination.Width = (int)(renderTarget.Width * scale);
            renderDestination.Height = (int)(renderTarget.Height * scale);

            renderDestination.X = (size.X - renderDestination.Width) / 2;
            renderDestination.Y = (size.Y - renderDestination.Height) / 2;
        }
        protected override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);
            sprRo = Content.Load<Texture2D>("sprRo_Wall");
            sprCave1_background = Content.Load<Texture2D>("spr_cave1_background");
            sprCave1_foreground = Content.Load<Texture2D>("spr_Cave1_foreground");
            sprCave1_walls = Content.Load<Texture2D>("spr_Cave1_walls");

            // Test Render Target
            renderTarget = new RenderTarget2D(GraphicsDevice, retroWidth, retroHeight);
        }

        protected override void Update(GameTime gameTime)
        {
            // Temporary quit game - eventually handle in a pause menu class
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
                Exit();

            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            // Test Render Target - Draw sprites to the render target
            GraphicsDevice.SetRenderTarget(renderTarget);

            // Test Sprite
            spriteBatch.Begin(samplerState: SamplerState.PointClamp);
            // Draw sprites here
            spriteBatch.Draw(sprCave1_background,new Vector2(0,0),Color.White);
            spriteBatch.Draw(sprRo, new Vector2(163, 63), Color.White);
            spriteBatch.Draw(sprCave1_walls, new Vector2(0, 0), Color.White);
            spriteBatch.Draw(sprCave1_foreground, new Vector2(0, 0), Color.White);
            spriteBatch.End();


            // Test Render Target - Draw render target to the screen
            GraphicsDevice.SetRenderTarget(null);
            spriteBatch.Begin(samplerState: SamplerState.PointClamp);
            spriteBatch.Draw(renderTarget, renderDestination, Color.White);
            spriteBatch.End();

            base.Draw(gameTime);
        }
    }
}