fixed hiddendoor tiles, now uses destruct shader no spriteset

grid/grid.go

@@ -109,10 +109,17 @@ func NewGrid(world *ecs.World,
 				entity := doormapper.New()
 				pos, render, destroyable = doormapper.Get(entity)
 				destroyable.Sprites = tile.Tiles
+				render.DamageImage = tile.Alpha
+				render.Shader = tile.Shader
+				render.Damaged = 0
 			default:
 				log.Fatalln("unsupported tile type encountered")
 			}
 
+			// FIXME:  this image  is never being  used because  it is
+			// being overwritten in game/levels.go:LevelToSlice(). The
+			// image is  taken from the LDTK map, not  from the Tile{}
+			// definition anymore
 			render.Image = tile.Sprite
 
 		default: