+ if (IN_ED_FIELD(sx, sy))
+ DrawMiniElement(sx, sy, element);
+}
+
+static void MergeAndCloseNeighbourElements(int x1, int y1, int *element1,
+ int x2, int y2, int *element2,
+ int (*close_function)(int, int),
+ boolean change_level)
+{
+ /* set neighbour elements to newly determined connections */
+ SetElementSimple(x1, y1, *element1, change_level);
+ SetElementSimple(x2, y2, *element2, change_level);
+
+ /* remove all open connections of neighbour elements */
+ *element1 = close_function(x1, y1);
+ *element2 = close_function(x2, y2);
+
+ /* set neighbour elements to new, minimized connections */
+ SetElementSimple(x1, y1, *element1, change_level);
+ SetElementSimple(x2, y2, *element2, change_level);
+}
+
+static void SetElementIntelliDraw(int x, int y, int new_element,
+ boolean change_level, int button)
+{
+ static int xy[4][2] =
+ {
+ { -1, 0 },
+ { +1, 0 },
+ { 0, -1 },
+ { 0, +1 }
+ };
+ static int last_x = -1;
+ static int last_y = -1;
+ int old_element = IntelliDrawBuffer[x][y];
+
+ if (new_element == EL_UNDEFINED)
+ {
+ last_x = -1;
+ last_y = -1;
+
+ return;
+ }
+
+ if (IS_TUBE(new_element))
+ {
+ int last_element_new = EL_UNDEFINED;
+ int direction = MV_NONE;
+ int i;
+
+ /* if old element is of same kind, keep all existing directions */
+ if (IS_TUBE(old_element))
+ direction |= getOpenDirectionFromTube(old_element);
+
+ for (i = 0; i < NUM_DIRECTIONS; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+
+ if (last_x == xx && last_y == yy && IN_LEV_FIELD(last_x, last_y) &&
+ IS_TUBE(IntelliDrawBuffer[last_x][last_y]))
+ {
+ int dir = MV_DIR_FROM_BIT(i);
+ int dir_opposite = MV_DIR_OPPOSITE(dir);
+ int last_element_old = IntelliDrawBuffer[last_x][last_y];
+ int last_direction_old = getOpenDirectionFromTube(last_element_old);
+ int last_direction_new = last_direction_old | dir_opposite;
+
+ last_element_new = getTubeFromOpenDirection(last_direction_new);
+
+ direction |= dir;
+ }
+ }
+
+ new_element = getTubeFromOpenDirectionNotEmpty(direction, new_element);
+
+ if (last_element_new != EL_UNDEFINED)
+ MergeAndCloseNeighbourElements(x, y, &new_element,
+ last_x, last_y, &last_element_new,
+ getClosedTube, change_level);
+ }
+ else if (IS_BELT(new_element))
+ {
+ int belt_nr = getBeltNrFromBeltElement(new_element);
+ int last_element_new = EL_UNDEFINED;
+ int direction = MV_NONE;
+ int i;
+
+ /* if old element is of same kind, keep all existing directions */
+ if (IS_BELT(old_element))
+ direction |= getOpenDirectionFromBelt(old_element);
+
+ for (i = MV_BIT_LEFT; i <= MV_BIT_RIGHT; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+
+ if (last_x == xx && last_y == yy && IN_LEV_FIELD(last_x, last_y) &&
+ IS_BELT(IntelliDrawBuffer[last_x][last_y]))
+ {
+ int dir = MV_DIR_FROM_BIT(i);
+ int dir_opposite = MV_DIR_OPPOSITE(dir);
+ int last_element_old = IntelliDrawBuffer[last_x][last_y];
+ int last_belt_nr = getBeltNrFromBeltElement(last_element_old);
+ int last_direction_old = getOpenDirectionFromBelt(last_element_old);
+ int last_direction_new = last_direction_old | dir_opposite;
+
+ last_element_new = getBeltFromNrAndOpenDirection(last_belt_nr,
+ last_direction_new);
+ direction |= dir;
+ }
+ }
+
+ new_element = getBeltFromNrAndOpenDirectionNotEmpty(belt_nr, direction,
+ new_element);
+ if (last_element_new != EL_UNDEFINED)
+ MergeAndCloseNeighbourElements(x, y, &new_element,
+ last_x, last_y, &last_element_new,
+ getClosedBelt, change_level);
+ }
+ else if (IS_ACID_POOL_OR_ACID(new_element))
+ {
+ int last_element_new = EL_UNDEFINED;
+ int direction = MV_NONE;
+ int i;
+
+ /* if old element is of same kind, keep all existing directions */
+ if (IS_ACID_POOL_OR_ACID(old_element))
+ direction |= getOpenDirectionFromPool(old_element);
+
+ for (i = 0; i < NUM_DIRECTIONS; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+
+ if (last_x == xx && last_y == yy && IN_LEV_FIELD(last_x, last_y) &&
+ IS_ACID_POOL_OR_ACID(IntelliDrawBuffer[last_x][last_y]))
+ {
+ int dir = MV_DIR_FROM_BIT(i);
+ int dir_opposite = MV_DIR_OPPOSITE(dir);
+ int last_element_old = IntelliDrawBuffer[last_x][last_y];
+ int last_direction_old = getOpenDirectionFromPool(last_element_old);
+ int last_direction_new = last_direction_old | dir_opposite;
+
+ last_element_new = getPoolFromOpenDirection(last_direction_new);
+
+ direction |= dir;
+ }
+ }
+
+ /* special corrections needed for intuitively correct acid pool drawing */
+ if (last_element_new == EL_EMPTY)
+ last_element_new = new_element;
+ else if (last_element_new != EL_UNDEFINED)
+ new_element = last_element_new;
+
+ new_element = getPoolFromOpenDirectionNotEmpty(direction, new_element);
+
+ if (last_element_new != EL_UNDEFINED)
+ MergeAndCloseNeighbourElements(x, y, &new_element,
+ last_x, last_y, &last_element_new,
+ getClosedPool, change_level);
+ }
+ else if (IS_EMC_PILLAR(new_element))
+ {
+ int last_element_new = EL_UNDEFINED;
+ int direction = MV_NONE;
+ int i;
+
+ /* if old element is of same kind, keep all existing directions */
+ if (IS_EMC_PILLAR(old_element))
+ direction |= getOpenDirectionFromPillar(old_element);
+
+ for (i = MV_BIT_UP; i <= MV_BIT_DOWN; i++)
+ {
+ int xx = x + xy[i][0];
+ int yy = y + xy[i][1];
+
+ if (last_x == xx && last_y == yy && IN_LEV_FIELD(last_x, last_y) &&
+ IS_EMC_PILLAR(IntelliDrawBuffer[last_x][last_y]))
+ {
+ int dir = MV_DIR_FROM_BIT(i);
+ int dir_opposite = MV_DIR_OPPOSITE(dir);
+ int last_element_old = IntelliDrawBuffer[last_x][last_y];
+ int last_direction_old = getOpenDirectionFromPillar(last_element_old);
+ int last_direction_new = last_direction_old | dir_opposite;