+void TestIfPlayerTouchesCustomElement(int x, int y)
+{
+ static boolean check_changing = FALSE;
+ static int xy[4][2] =
+ {
+ { 0, -1 },
+ { -1, 0 },
+ { +1, 0 },
+ { 0, +1 }
+ };
+ int i;
+
+ if (check_changing) /* prevent this function from running into a loop */
+ return;
+
+ check_changing = TRUE;
+
+ for (i=0; i<4; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+
+ if (!IN_LEV_FIELD(xx, yy))
+ continue;
+
+ if (IS_PLAYER(x, y))
+ {
+ CheckTriggeredElementChange(xx, yy, Feld[xx][yy], CE_OTHER_GETS_TOUCHED);
+ CheckElementChange(xx, yy, Feld[xx][yy], CE_TOUCHED_BY_PLAYER);
+ }
+ else if (IS_PLAYER(xx, yy))
+ {
+ CheckTriggeredElementChange(x, y, Feld[x][y], CE_OTHER_GETS_TOUCHED);
+ CheckElementChange(x, y, Feld[x][y], CE_TOUCHED_BY_PLAYER);
+
+ break;
+ }
+ }
+
+ check_changing = FALSE;
+}
+
+void TestIfElementTouchesCustomElement(int x, int y)
+{
+ static boolean check_changing = FALSE;
+ static int xy[4][2] =
+ {
+ { 0, -1 },
+ { -1, 0 },
+ { +1, 0 },
+ { 0, +1 }
+ };
+ boolean change_center_element = FALSE;
+ int center_element = Feld[x][y];
+ int i;
+
+ if (check_changing) /* prevent this function from running into a loop */
+ return;
+
+ check_changing = TRUE;
+
+ for (i=0; i<4; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+ int border_element;
+
+ if (!IN_LEV_FIELD(xx, yy))
+ continue;
+
+ border_element = Feld[xx][yy];
+
+ /* check for change of center element (but change it only once) */
+ if (IS_CUSTOM_ELEMENT(center_element) &&
+ border_element == element_info[center_element].change.trigger_element)
+ change_center_element = TRUE;
+
+ /* check for change of border element */
+ if (IS_CUSTOM_ELEMENT(border_element) &&
+ center_element == element_info[border_element].change.trigger_element)
+ CheckElementChange(xx, yy, border_element, CE_OTHER_IS_TOUCHING);
+ }
+
+ if (change_center_element)
+ CheckElementChange(x, y, center_element, CE_OTHER_IS_TOUCHING);
+
+ check_changing = FALSE;
+}
+