Implement wasDestroyed check on FlxGraphic

flixel/FlxCamera.hx

@@ -635,6 +635,11 @@ class FlxCamera extends FlxBasic
 			itemToReturn = new FlxDrawItem();
 		}
 
+		if (graphic.wasDestroyed) {
+			// Throw an exception here, because throwing in `FlxDrawQuadsItem.render()` is not helpful.
+			throw 'Attempted to queue invalid FlxDrawItem, did you dispose of a cached sprite?';
+		}
+
 		itemToReturn.graphics = graphic;
 		itemToReturn.antialiasing = smooth;
 		itemToReturn.colored = colored;

flixel/graphics/FlxGraphic.hx

@@ -343,6 +343,16 @@ class FlxGraphic implements IFlxDestroyable
 	 */
 	public var atlasFrames(get, never):FlxAtlasFrames;
 
+	/**
+	 * This value is `true` if this graphic has been disposed.
+	 * Attempting to render a disposed graphic will cause an error.
+	 */
+	public var wasDestroyed(get, never):Bool;
+
+	function get_wasDestroyed():Bool {
+		return shader == null;
+	}
+
 	/**
 	 * Storage for all available frame collection of all types for this graphic object.
 	 */

flixel/graphics/tile/FlxDrawQuadsItem.hx

@@ -115,6 +115,12 @@ class FlxDrawQuadsItem extends FlxDrawBaseItem<FlxDrawQuadsItem>
 			return;
 
 		var shader = shader != null ? shader : graphics.shader;
+
+		if (shader == null) {
+			// If this gets called, the check for `graphic.wasDestroyed` in FlxCamera failed.
+			throw 'Attempted to render invalid FlxDrawItem, did you dispose of a cached sprite?';
+		}
+
 		shader.bitmap.input = graphics.bitmap;
 		shader.bitmap.filter = (camera.antialiasing || antialiasing) ? LINEAR : NEAREST;
 		shader.alpha.value = alphas;