Respect sprite X and Y offsets

This makes menus display more correctly, and also fixes trees and other
objects on the main map, although it messes up bounds clipping (sigh).

internal/assetstore/map.go

@@ -4,8 +4,6 @@ import (
 	"image"
 	"log"
 
-	"github.com/hajimehoshi/ebiten"
-
 	"code.ur.gs/lupine/ordoor/internal/maps"
 )
 
@@ -64,11 +62,11 @@ func (a *AssetStore) Map(name string) (*Map, error) {
 	return m, nil
 }
 
-// ImagesForCell returns the sprites needed to correctly render this cell.
+// SpritesForCell returns the sprites needed to correctly render this cell.
 // They should be rendered from first to last to get the correct ordering
-func (m *Map) ImagesForCell(x, y, z int) ([]*ebiten.Image, error) {
+func (m *Map) SpritesForCell(x, y, z int) ([]*Sprite, error) {
 	cell := m.raw.At(x, y, z)
-	images := make([]*ebiten.Image, 0, 4)
+	sprites := make([]*Sprite, 0, 4)
 
 	for _, ref := range []maps.ObjRef{cell.Surface, cell.Right, cell.Left, cell.Center} {
 		if !ref.IsActive() {
@@ -80,13 +78,13 @@ func (m *Map) ImagesForCell(x, y, z int) ([]*ebiten.Image, error) {
 			return nil, err
 		}
 
-		img, err := obj.Image(ref.Sprite())
+		sprite, err := obj.Sprite(ref.Sprite())
 		if err != nil {
 			return nil, err
 		}
 
-		images = append(images, img)
+		sprites = append(sprites, sprite)
 	}
 
-	return images, nil
+	return sprites, nil
 }