CWater* lua_towater ( lua_State* luaVM, int iArgument )
{
CElement* pElement = lua_toelement ( luaVM, iArgument );
if ( pElement && IS_WATER ( pElement ) )
return static_cast < CWater* > ( pElement );
else
return NULL;
}
static void overfill_lake(int x, int y, Shoreline * shore, int lake_id)
{
// Starting point is a local minimum
// Lake growth is done iteratively by flooding the lowest shore point and rising water level
// shore point = neighbour without water
// (at this point we have no water in the map, except other lakes and rivers)
//
// We have a list of shore points sorted by altitude
int i, level;
if (is_border(x, y))
return;
set_river_tile(x, y);
level = ALT(x, y);
// find neighbours
for (i = 0; i < 8; i++) {
if (in_map(x + di[i], y + dj[i]) && !IS_WATER(x + di[i], y + dj[i]))
try_shore_point(x + di[i], y + dj[i], shore);
}
if (shore->next != NULL) {
shore = shore->next;
x = shore->x;
y = shore->y;
if ((ALT(x, y) < level)) {
set_river_tile(x, y);
// create river and continue to build shoreline
// we will continue to overfill (from a lower point) until we reach border of the map
//fprintf(stdout, "We found a pass x %i, y %i, alt %i \n", x, y, ALT(x,y));
setup_one_river(x, y, lake_id, shore);
}
overfill_lake(x, y, shore, lake_id);
} else {
// Q: ? Should this happen ?
// A: yes if we are in a lake that was previously filled by a higher one which overfilled here
// else ? it should not happen ?
//fprintf(stderr,"the shoreline list is empty, x = %i, y = %i\n", x, y);
}
}
static int setup_one_river(int xx, int yy, int lake_id, Shoreline * shore)
{
int alt_max, x, y, alt, x0, y0;
// start a river from point (xx, yy)
set_river_tile(xx, yy);
alt_max = ALT(xx, yy);
x0 = xx;
y0 = yy;
/* follow most important slope and go downward */
while (((xx != x) || (yy != y)) && (xx != 0) && (xx != (WORLD_SIDE_LEN - 1)) && (yy != 0)
&& (yy != WORLD_SIDE_LEN - 1)) {
int m = 0;
x = xx;
y = yy;
alt = ALT(x, y);
for (int n = 0; n < 8; n++) {
if (in_map(x + di[n], y + dj[n])) {
if (ALT(x + di[n], y + dj[n]) < alt) {
xx = x + di[n];
yy = y + dj[n];
alt = ALT(xx, yy);
m = n;
}
// find neighbours and update shore line if needed
// may mark as shoreline a point which will be set as river later. We don't care
if (!IS_WATER(x + di[n], y + dj[n]))
try_shore_point(x + di[n], y + dj[n], shore);
}
}
set_river_tile(xx, yy);
if (m > 3) {
// we did diagonal move, so we need to connect river
if (ALT(x + di[m], y) > ALT(x, y + dj[m]))
set_river_tile(x, y + dj[m]);
else
set_river_tile(x + di[m], y);
}
};
// We are in a local minimum or at the borders of the map (strictly the lowest points)
}
