From b06155aa886ac1917c0cd6c1e8a5147e05cfc63c Mon Sep 17 00:00:00 2001
From: Colin McMillen <colin@semicolin.games>
Date: Wed, 19 Feb 2020 15:00:29 -0500
Subject: [PATCH] Render backgrounds from back-to-front in an array.

GitOrigin-RevId: 1f4ca760d4dc4a73a4f96f6b04ee2929e789a5eb
---
 Shared/Scene.cs    | 34 ++++++++++------------------------
 Shared/Textures.cs | 14 ++++++--------
 2 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/Shared/Scene.cs b/Shared/Scene.cs
index e81f734..3e70022 100644
--- a/Shared/Scene.cs
+++ b/Shared/Scene.cs
@@ -44,36 +44,22 @@ namespace SemiColinGames {
         return;
       }
 
+      // Draw scene to sceneTarget.
       graphics.SetRenderTarget(sceneTarget);
       graphics.Clear(backgroundColor);
 
-      // Draw scene to sceneTarget.
-      spriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.LinearWrap, null, null);
-
       // Draw background.
-
-      // We assume that all backgrounds are the same size; if not, the computation of yOffset needs
-      // to be computed separately for every background.
-      int yOffset = Textures.Background1.Height - camera.Height - 64;
-      Color bgBlend = Color.FromNonPremultiplied(new Vector4(1, 1, 1, 1));
+      spriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.LinearWrap, null, null);
       Rectangle bgTarget = new Rectangle(0, 0, camera.Width, camera.Height);
 
-      Rectangle bgSource = new Rectangle(
-        (int) (camera.Left * 1f / 16), yOffset, camera.Width, camera.Height);
-      spriteBatch.Draw(Textures.Background1, bgTarget, bgSource, bgBlend);
-
-      bgSource = new Rectangle(
-        (int) (camera.Left * 1f / 8), yOffset, camera.Width, camera.Height);
-      spriteBatch.Draw(Textures.Background2, bgTarget, bgSource, bgBlend);
-
-      bgSource = new Rectangle(
-        (int) (camera.Left * 1f / 4), yOffset, camera.Width, camera.Height);
-      spriteBatch.Draw(Textures.Background3, bgTarget, bgSource, bgBlend);
-
-      bgSource = new Rectangle(
-        (int) (camera.Left * 1f / 2), yOffset, camera.Width, camera.Height);
-      spriteBatch.Draw(Textures.Background4, bgTarget, bgSource, bgBlend);
-
+      float xScale = 1f / 16;
+      for (int i = 0; i < Textures.Backgrounds.Length; i++) {
+        int yOffset = Textures.Backgrounds[i].Height - camera.Height - 24;
+        Rectangle bgSource = new Rectangle(
+          (int) (camera.Left * xScale), yOffset, camera.Width, camera.Height);
+        spriteBatch.Draw(Textures.Backgrounds[i], bgTarget, bgSource, Color.White);
+        xScale *= 2;
+      }
       spriteBatch.End();
 
       // Set up transformation matrix for drawing world objects.
diff --git a/Shared/Textures.cs b/Shared/Textures.cs
index 1241fe1..2392271 100644
--- a/Shared/Textures.cs
+++ b/Shared/Textures.cs
@@ -6,10 +6,8 @@ namespace SemiColinGames {
 
     public static Texture2D Player;
 
-    public static Texture2D Background1;
-    public static Texture2D Background2;
-    public static Texture2D Background3;
-    public static Texture2D Background4;
+    // Backgrounds are indexed by draw order; the first element should be drawn furthest back.
+    public static Texture2D[] Backgrounds = new Texture2D[4];
 
     public static Texture2D Cemetery;
     public static Texture2D Crypt;
@@ -27,10 +25,10 @@ namespace SemiColinGames {
     public static void Load(ContentManager content) {
       Player = content.Load<Texture2D>("sprites/ccg/ninja_female");
 
-      Background1 = content.Load<Texture2D>("backgrounds/szadiart/pf4/background1_day");
-      Background2 = content.Load<Texture2D>("backgrounds/szadiart/pf4/background2a_day");
-      Background3 = content.Load<Texture2D>("backgrounds/szadiart/pf4/background3_day");
-      Background4 = content.Load<Texture2D>("backgrounds/szadiart/pf4/background4_day");
+      Backgrounds[0] = content.Load<Texture2D>("backgrounds/szadiart/pf4/background1_day");
+      Backgrounds[1] = content.Load<Texture2D>("backgrounds/szadiart/pf4/background2a_day");
+      Backgrounds[2] = content.Load<Texture2D>("backgrounds/szadiart/pf4/background3_day");
+      Backgrounds[3] = content.Load<Texture2D>("backgrounds/szadiart/pf4/background4_day");
 
       Cemetery = content.Load<Texture2D>("tiles/anokolisa/cemetery");
       Crypt = content.Load<Texture2D>("tiles/anokolisa/crypt");