basic scrolling world!

GitOrigin-RevId: 6c08535f1ace172f9f08479ced5e9dc8b0663102

Jumpy.Shared/Camera.cs

@@ -1,10 +1,24 @@
-using System;
+using Microsoft.Xna.Framework;
-using System.Collections.Generic;
+using System;
-using System.Text;
 
 namespace Jumpy {
   class Camera {
-    public const int Width = 1920 / 6;
+    private Rectangle bbox = new Rectangle(0, 0, 1920 / 6, 1080 / 6);
-    public const int Height = 1080 / 6;
+
+    public int Width { get => bbox.Width; }
+    public int Height { get => bbox.Height; }
+    public int Left { get => bbox.Left; }
+
+    public void Update(GameTime time, Point player) {
+      int diff = player.X - bbox.Center.X;
+      // TODO: use the actual center of the player's bbox.
+      if (Math.Abs(diff) > 16) {
+        bbox.Offset((int) (diff * 0.1), 0);
+      }
+      if (bbox.Left < 0) {
+        bbox.Offset(-bbox.Left, 0);
+      }
+      Debug.Toast($"p: {player.X} c: {bbox.Center.X}");
+    }
   }
 }

Jumpy.Shared/Debug.cs

@@ -18,6 +18,11 @@ namespace Jumpy {
     public static bool Enabled;
     static List<DebugRect> rects = new List<DebugRect>();
     static Texture2D whiteTexture;
+    static string toast = null;
+
+    public static void Toast(string s) {
+      toast = s;
+    }
 
     public static void WriteLine(string s) {
       System.Diagnostics.Debug.WriteLine(s);
@@ -40,12 +45,22 @@ namespace Jumpy {
       rects.Add(new DebugRect(rect, color));
     }
 
-    public static void Draw(SpriteBatch spriteBatch) {
+    public static void DrawToast(SpriteBatch spriteBatch, SpriteFont font) {
+      // TODO: this use of toast isn't thread-safe.
+      if (toast == null) {
+        return;
+      }
+      spriteBatch.DrawString(font, toast, new Vector2(10, 10), Color.YellowGreen);
+      toast = null;
+    }
+
+    public static void Draw(SpriteBatch spriteBatch, Camera camera) {
       if (!Enabled) {
         return;
       }
       foreach (var debugRect in rects) {
         var rect = debugRect.rect;
+        rect.Offset(-camera.Left, 0);
         var color = debugRect.color;
         // top side
         spriteBatch.Draw(

Jumpy.Shared/JumpyGame.cs

@@ -29,6 +29,7 @@ namespace Jumpy {
 
     Player player;
     World world;
+    Camera camera = new Camera();
 
     public JumpyGame() {
       graphics = new GraphicsDeviceManager(this);
@@ -46,7 +47,7 @@ namespace Jumpy {
 
       for (int i = 0; i < renderTargets.Length; i++) {
         renderTargets[i] = new RenderTarget2D(
-          GraphicsDevice, Camera.Width, Camera.Height, false /* mipmap */,
+          GraphicsDevice, camera.Width, camera.Height, false /* mipmap */,
           GraphicsDevice.PresentationParameters.BackBufferFormat, DepthFormat.Depth24);
       }
 
@@ -95,6 +96,8 @@ namespace Jumpy {
       List<Rectangle> collisionTargets = world.CollisionTargets();
       player.Update(gameTime, gamePad, collisionTargets);
 
+      camera.Update(gameTime, player.Position);
+
       base.Update(gameTime);
     }
 
@@ -109,23 +112,25 @@ namespace Jumpy {
       renderTargetIdx = (renderTargetIdx + 1) % renderTargets.Length;
       GraphicsDevice.SetRenderTarget(renderTarget);
       GraphicsDevice.Clear(Color.CornflowerBlue);
-      spriteBatch.Begin();
+      spriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.LinearWrap, null, null);
 
       // Draw background.
       Rectangle bgSource = new Rectangle(
-        0, grasslandBg1.Height - Camera.Height, Camera.Width, Camera.Height);
+        (int) (camera.Left * 0.25), grasslandBg1.Height - camera.Height, camera.Width, camera.Height);
-      Rectangle bgTarget = new Rectangle(0, 0, Camera.Width, Camera.Height);
+      Rectangle bgTarget = new Rectangle(0, 0, camera.Width, camera.Height);
       spriteBatch.Draw(grasslandBg2, bgTarget, bgSource, Color.White);
+      bgSource = new Rectangle(
+        (int) (camera.Left * 0.5), grasslandBg1.Height - camera.Height, camera.Width, camera.Height);
       spriteBatch.Draw(grasslandBg1, bgTarget, bgSource, Color.White);
 
       // Draw player.
-      player.Draw(gameTime, spriteBatch);
+      player.Draw(spriteBatch, camera, gameTime);
 
       // Draw foreground tiles.
-      world.Draw(spriteBatch);
+      world.Draw(spriteBatch, camera);
 
       // Draw debug rects.
-      Debug.Draw(spriteBatch);
+      Debug.Draw(spriteBatch, camera);
 
       // Aaaaand we're done.
       spriteBatch.End();
@@ -143,9 +148,11 @@ namespace Jumpy {
       if (Debug.Enabled) {
         string fpsText = $"{GraphicsDevice.Viewport.Width}x{GraphicsDevice.Viewport.Height}, " +
           $"{fpsCounter.Fps} FPS";
-        spriteBatch.DrawString(font, fpsText, new Vector2(10, 10), Color.White);
+        spriteBatch.DrawString(font, fpsText, new Vector2(10, 40), Color.YellowGreen);
       }
 
+      Debug.DrawToast(spriteBatch, font);
+
       spriteBatch.End();
 
       base.Draw(gameTime);

Jumpy.Shared/Player.cs

@@ -17,7 +17,7 @@ namespace Jumpy {
     private const int jumpSpeed = 600;
     private const int gravity = 2400;
 
-    private Point position = new Point(Camera.Width / 2, 10);
+    private Point position = new Point(64, 16);
     private Facing facing = Facing.Right;
     private Pose pose = Pose.Standing;
     private AirState airState = AirState.Ground;
@@ -29,6 +29,8 @@ namespace Jumpy {
       this.texture = texture;
     }
 
+    public Point Position { get { return position; } }
+
     private Rectangle Bbox(Point position) {
       return new Rectangle(position.X - spriteWidth, position.Y - 7, spriteWidth * 2, 26);
     }
@@ -150,7 +152,8 @@ namespace Jumpy {
         pose = Pose.Jumping;
       }
    
-      position.X = Math.Min(Math.Max(position.X, 0 + spriteWidth), Camera.Width - spriteWidth);
+      // TODO: also bound player position by the right edge of the World?
+      position.X = Math.Max(position.X, 0 + spriteWidth);
     }
 
     private int spritePosition(Pose pose, GameTime time) {
@@ -187,14 +190,14 @@ namespace Jumpy {
       }
     }
 
-    public void Draw(GameTime time, SpriteBatch spriteBatch) {
+    public void Draw(SpriteBatch spriteBatch, Camera camera, GameTime time) {
       // TODO: don't create so many "new" things that could be cached / precomputed.
       int index = spritePosition(pose, time);
       Rectangle textureSource = new Rectangle(index * spriteSize, 0, spriteSize, spriteSize);
       Vector2 spriteCenter = new Vector2(spriteSize / 2, spriteSize / 2);
       SpriteEffects effect = facing == Facing.Right ?
         SpriteEffects.FlipHorizontally : SpriteEffects.None;
-      Vector2 drawPos = new Vector2(position.X, position.Y);
+      Vector2 drawPos = new Vector2(position.X - camera.Left, position.Y);
       spriteBatch.Draw(texture, drawPos, textureSource, Color.White, 0f, spriteCenter,
         Vector2.One, effect, 0f);
     }

Jumpy.Shared/World.cs

@@ -27,33 +27,34 @@ namespace Jumpy {
     public Rectangle Position { get { return position; } }
     public Terrain Terrain { get { return terrain; } }
 
-    public void Draw(SpriteBatch spriteBatch) {
+    public void Draw(SpriteBatch spriteBatch, Camera camera) {
       int size = World.TileSize;
+      Vector2 drawPos = new Vector2(position.Left - camera.Left, position.Top);
       switch (terrain) {
         case Terrain.Grass: {
           // TODO: hold these rectangles statically instead of making them anew constantly.
           Rectangle source = new Rectangle(3 * size, 0 * size, size, size);
-          spriteBatch.Draw(texture, position, source, Color.White);
+          spriteBatch.Draw(texture, drawPos, source, Color.White);
           break;
         }
         case Terrain.GrassL: {
             Rectangle source = new Rectangle(2 * size, 0 * size, size, size);
-            spriteBatch.Draw(texture, position, source, Color.White);
+            spriteBatch.Draw(texture, drawPos, source, Color.White);
             break;
           }
         case Terrain.GrassR: {
             Rectangle source = new Rectangle(4 * size, 0 * size, size, size);
-            spriteBatch.Draw(texture, position, source, Color.White);
+            spriteBatch.Draw(texture, drawPos, source, Color.White);
             break;
           }
         case Terrain.Rock: {
           Rectangle source = new Rectangle(3 * size, 1 * size, size, size);
-          spriteBatch.Draw(texture, position, source, Color.White);
+          spriteBatch.Draw(texture, drawPos, source, Color.White);
           break;
         }
         case Terrain.Water: {
           Rectangle source = new Rectangle(9 * size, 2 * size, size, size);
-          spriteBatch.Draw(texture, position, source, Color.White);
+          spriteBatch.Draw(texture, drawPos, source, Color.White);
           break;
         }
         case Terrain.Empty:
@@ -74,18 +75,18 @@ namespace Jumpy {
     public int Height { get; }
 
     string[] worldDesc = new string[] {
-"                    ",
+"                                                                                   .",
-"                    ",
+"                                                                                   .",
-"                    ",
+"                                                                                   .",
-"               <=>  ",
+"               <=>           ===                                                   .",
-"                    ",
+"                                                                                   .",
-"                    ",
+"                                                                                   .",
-"         <=>  <=>   ",
+"         <=>  <=>  ========       ==                                               .",
-"     =              ",
+"     =                               ==                                            .",
-"                    ",
+"                                         ==                                        .",
-"                    ",
+"                                                                                   .",
-"=============>  <===",
+"=============>  <==================================================================.",
-"..............~~~~~." };
+"..............~~~~~................................................................." };
 
     public World(Texture2D texture) {
       // TODO: better error handling for if the string[] isn't rectangular.
@@ -122,10 +123,10 @@ namespace Jumpy {
       }
     }
 
-    public void Draw(SpriteBatch spriteBatch) {
+    public void Draw(SpriteBatch spriteBatch, Camera camera) {
       for (int j = 0; j < height; j++) {
         for (int i = 0; i < width; i++) {
-          tiles[i, j].Draw(spriteBatch);
+          tiles[i, j].Draw(spriteBatch, camera);
         }
       }
     }