Method getEffectScreenPos

用于在两组大小不等的瓦片中计算某特效位置 @param gx @param gy @param cellWidth @param cellHeight @param config @param offsetX @param offsetY @param result @return

(int gx, int gy, float cellWidth, float cellHeight, IsoConfig config,
			float offsetX, float offsetY, Vector2f result)