Parallax (#131)

Content.Client/Parallax/ParallaxOverlay.cs

@@ -0,0 +1,63 @@
+using Content.Client.Interfaces.Parallax;
+using SS14.Client.Graphics;
+using SS14.Client.Graphics.Drawing;
+using SS14.Client.Graphics.Overlays;
+using SS14.Client.Graphics.Shaders;
+using SS14.Client.Interfaces.Graphics.ClientEye;
+using SS14.Client.Interfaces.Graphics.Overlays;
+using SS14.Shared.IoC;
+using SS14.Shared.Maths;
+using SS14.Shared.Prototypes;
+
+namespace Content.Client.Parallax
+{
+    public class ParallaxOverlay : Overlay
+    {
+#pragma warning disable 649
+        [Dependency] private readonly IParallaxManager _parallaxManager;
+        [Dependency] private readonly IEyeManager _eyeManager;
+        [Dependency] private readonly IPrototypeManager _prototypeManager;
+#pragma warning restore 649
+
+        public override bool AlwaysDirty => true;
+        private const float Slowness = 0.5f;
+
+        private Texture _parallaxTexture;
+
+        public override OverlaySpace Space => OverlaySpace.ScreenSpaceBelowWorld;
+
+        public ParallaxOverlay() : base(nameof(ParallaxOverlay))
+        {
+            IoCManager.InjectDependencies(this);
+            Shader = _prototypeManager.Index<ShaderPrototype>("unshaded").Instance();
+
+            if (_parallaxManager.ParallaxTexture == null)
+            {
+                _parallaxManager.OnTextureLoaded += texture => _parallaxTexture = texture;
+            }
+            else
+            {
+                _parallaxTexture = _parallaxManager.ParallaxTexture;
+            }
+        }
+
+        protected override void Draw(DrawingHandle handle)
+        {
+            if (_parallaxTexture == null)
+            {
+                return;
+            }
+
+            var (sizeX, sizeY) = _parallaxTexture.Size;
+            var (posX, posY) = _eyeManager.ScreenToWorld(Vector2.Zero).ToWorld().Position;
+            var (ox, oy) = (Vector2i) new Vector2(-posX / Slowness, posY / Slowness);
+            ox = MathHelper.Mod(ox, sizeX);
+            oy = MathHelper.Mod(oy, sizeY);
+
+            handle.DrawTexture(_parallaxTexture, new Vector2(ox, oy));
+            handle.DrawTexture(_parallaxTexture, new Vector2(ox - sizeX, oy));
+            handle.DrawTexture(_parallaxTexture, new Vector2(ox, oy - sizeY));
+            handle.DrawTexture(_parallaxTexture, new Vector2(ox - sizeX, oy - sizeY));
+        }
+    }
+}