Added Underwater Switch Controller

Author: maddie480

Ahorn/entities/underwaterSwitchController.jl

@@ -0,0 +1,21 @@
+module SpringCollab2020UnderwaterSwitchController
+
+using ..Ahorn, Maple
+
+@mapdef Entity "SpringCollab2020/UnderwaterSwitchController" UnderwaterSwitchController(x::Integer, y::Integer, flag::String="underwater_switch")
+
+const placements = Ahorn.PlacementDict(
+    "Underwater Switch Controller (Spring Collab 2020)" => Ahorn.EntityPlacement(
+        UnderwaterSwitchController
+    )
+)
+
+function Ahorn.selection(entity::UnderwaterSwitchController)
+    x, y = Ahorn.position(entity)
+
+    return Ahorn.Rectangle(x - 12, y - 12, 24, 24)
+end
+
+Ahorn.render(ctx::Ahorn.Cairo.CairoContext, entity::UnderwaterSwitchController, room::Maple.Room) = Ahorn.drawImage(ctx, Ahorn.Assets.northernLights, -12, -12)
+
+end

Ahorn/lang/en_gb.lang

@@ -89,4 +89,7 @@ placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.persistent=If enabl
 placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.inactiveColor=The gate icon colour when not triggered yet.
 placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.activeColor=The gate icon colour when triggered, but the group is not complete yet.
 placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.finishColor=The gate icon colour when the group is complete.
-placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.sprite=The texture for the gate block.
+placements.entities.SpringCollab2020/FlagSwitchGate.tooltips.sprite=The texture for the gate block.
+
+# Underwater Switch Controller
+placements.entities.SpringCollab2020/UnderwaterSwitchController.tooltips.flag=When this session flag is set, the whole room will be covered with water.

Entities/UnderwaterSwitchController.cs

@@ -0,0 +1,69 @@
+using Celeste.Mod.Entities;
+using Microsoft.Xna.Framework;
+using Monocle;
+using System.Collections;
+using System.Reflection;
+
+namespace Celeste.Mod.SpringCollab2020.Entities {
+    [CustomEntity("SpringCollab2020/UnderwaterSwitchController")]
+    class UnderwaterSwitchController : Entity {
+        private static FieldInfo waterFill = typeof(Water).GetField("fill", BindingFlags.NonPublic | BindingFlags.Instance);
+
+        private string flag;
+        private Water water;
+
+        public UnderwaterSwitchController(EntityData data, Vector2 offset) : base(data.Position + offset) {
+            flag = data.Attr("flag");
+
+            Add(new Coroutine(Routine()));
+
+            Add(new TransitionListener() {
+                OnInBegin = () => {
+                    // when transitioning in a room with a controller and the flag is already set, spawn water right away
+                    Session session = SceneAs<Level>().Session;
+                    if (session.GetFlag(flag)) {
+                        spawnWater(session.LevelData.Bounds);
+                    }
+                }
+            });
+        }
+
+        public IEnumerator Routine() {
+            Session session = SceneAs<Level>().Session;
+            while (true) {
+                // wait until the flag is set.
+                while (!session.GetFlag(flag)) {
+                    yield return null;
+                }
+
+                // spawn water.
+                if (water == null) {
+                    spawnWater(session.LevelData.Bounds);
+                }
+
+                // wait until the flag is set.
+                while (session.GetFlag(flag)) {
+                    yield return null;
+                }
+
+                // make water go away.
+                Scene.Remove(water);
+                water = null;
+            }
+        }
+
+        private void spawnWater(Rectangle levelBounds) {
+            // flood the room with water, make the water 10 pixels over the top to prevent a "splash" effect when going in a room above.
+            water = new Water(new Vector2(levelBounds.Left, levelBounds.Top - 10),
+                false, false, levelBounds.Width, levelBounds.Height + 10);
+
+            // but we don't want the water to render off-screen, because it is visible on upwards transitions.
+            Rectangle fill = (Rectangle) waterFill.GetValue(water);
+            fill.Y += 10;
+            fill.Height -= 10;
+            waterFill.SetValue(water, fill);
+
+            Scene.Add(water);
+        }
+    }
+}