+
+/* values for change events for custom elements */
+#define CE_DELAY 0
+#define CE_TOUCHED_BY_PLAYER 1
+#define CE_PRESSED_BY_PLAYER 2
+#define CE_PUSHED_BY_PLAYER 3
+#define CE_IMPACT 4
+#define CE_SMASHED 5
+#define CE_OTHER_COLLECTING 6
+#define CE_OTHER_PUSHING 7
+#define CE_OTHER_CHANGING 8
+#define CE_OTHER_EXPLODING 9
+
+/* values for internal purpose only (level editor) */
+#define CE_BY_PLAYER 10
+#define CE_IMPACT_SMASHED 11
+#define CE_BY_OTHER 12
+
+#define NUM_CHANGE_EVENTS 13
+
+#define CE_BITMASK_DEFAULT 0
+
+#define CH_EVENT_BIT(c) (1 << (c))
+#define CH_EVENT_VAR(e) (element_info[e].change.events)
+
+#define HAS_CHANGE_EVENT(e,c) (IS_CUSTOM_ELEMENT(e) && \
+ (CH_EVENT_VAR(e) & CH_EVENT_BIT(c)) != 0)
+#define SET_CHANGE_EVENT(e,c,v) (IS_CUSTOM_ELEMENT(e) ? \
+ ((v) ? \
+ (CH_EVENT_VAR(e) |= CH_EVENT_BIT(c)) : \
+ (CH_EVENT_VAR(e) &= ~CH_EVENT_BIT(c))) : 0)
+
+