/* * static char *rcsid_los_c = * "$Id: los.c 11578 2009-02-23 22:02:27Z lalo $"; */ /* CrossFire, A Multiplayer game for X-windows Copyright (C) 2002-2006 Mark Wedel & Crossfire Development Team Copyright (C) 1992 Frank Tore Johansen This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. The authors can be reached via e-mail at crossfire-devel@real-time.com */ /** * @file los.c * This handles the "line of sight" for players and monsters. */ /* Nov 95 - inserted USE_LIGHTING code stuff in here - b.t. */ #include #include /** * Distance must be less than this for the object to be blocked. * An object is 1.0 wide, so if set to 0.5, it means the object * that blocks half the view (0.0 is complete block) will * block view in our tables. * .4 or less lets you see through walls. .5 is about right. */ #define SPACE_BLOCK 0.5 typedef struct blstr { int x[4], y[4]; int index; } blocks; static blocks block[MAP_CLIENT_X][MAP_CLIENT_Y]; static void expand_lighted_sight(object *op); /** * What this sets is that x,y blocks the view of bx,by * This then sets up a relation - for example, something * at 5,4 blocks view at 5,3 which blocks view at 5,2 * etc. So when we check 5,4 and find it blocks, we have * the data to know that 5,3 and 5,2 and 5,1 should also * be blocked. * Used to initialise the array used by the LOS routines. * * @param x * @param y * coordinates that block. * @param bx * @param by * coordinates that get blocked. * @todo * check index for overflow? */ static void set_block(int x, int y, int bx, int by) { int index = block[x][y].index, i; /* Due to flipping, we may get duplicates - better safe than sorry. */ for (i = 0; i < index; i++) { if (block[x][y].x[i] == bx && block[x][y].y[i] == by) return; } block[x][y].x[index] = bx; block[x][y].y[index] = by; block[x][y].index++; #ifdef LOS_DEBUG LOG(llevDebug, "setblock: added %d %d -> %d %d (%d)\n", x, y, bx, by, block[x][y].index); #endif } /** * initialises the array used by the LOS routines. * * Since we are only doing the upper left quadrant, only * these spaces could possibly get blocked, since these * are the only ones further out that are still possibly in the * sightline. */ void init_block(void) { int x, y, dx, dy, i; static const int block_x[3] = { -1, -1, 0 }, block_y[3] = { -1, 0, -1 }; for (x = 0; x < MAP_CLIENT_X; x++) for (y = 0; y < MAP_CLIENT_Y; y++) { block[x][y].index = 0; } /* The table should be symmetric, so only do the upper left * quadrant - makes the processing easier. */ for (x = 1; x <= MAP_CLIENT_X/2; x++) { for (y = 1; y <= MAP_CLIENT_Y/2; y++) { for (i = 0; i < 3; i++) { dx = x+block_x[i]; dy = y+block_y[i]; /* center space never blocks */ if (x == MAP_CLIENT_X/2 && y == MAP_CLIENT_Y/2) continue; /* If its a straight line, its blocked */ if ((dx == x && x == MAP_CLIENT_X/2) || (dy == y && y == MAP_CLIENT_Y/2)) { /* For simplicity, we mirror the coordinates to block the other * quadrants. */ set_block(x, y, dx, dy); if (x == MAP_CLIENT_X/2) { set_block(x, MAP_CLIENT_Y-y-1, dx, MAP_CLIENT_Y-dy-1); } else if (y == MAP_CLIENT_Y/2) { set_block(MAP_CLIENT_X-x-1, y, MAP_CLIENT_X-dx-1, dy); } } else { float d1, r, s, l; /* We use the algorihm that found out how close the point * (x,y) is to the line from dx,dy to the center of the viewable * area. l is the distance from x,y to the line. * r is more a curiosity - it lets us know what direction (left/right) * the line is off */ d1 = (float)(pow(MAP_CLIENT_X/2-dx, 2)+pow(MAP_CLIENT_Y/2-dy, 2)); r = (float)((dy-y)*(dy-MAP_CLIENT_Y/2)-(dx-x)*(MAP_CLIENT_X/2-dx))/d1; s = (float)((dy-y)*(MAP_CLIENT_X/2-dx)-(dx-x)*(MAP_CLIENT_Y/2-dy))/d1; l = FABS(sqrt(d1)*s); if (l <= SPACE_BLOCK) { /* For simplicity, we mirror the coordinates to block the other * quadrants. */ set_block(x, y, dx, dy); set_block(MAP_CLIENT_X-x-1, y, MAP_CLIENT_X-dx-1, dy); set_block(x, MAP_CLIENT_Y-y-1, dx, MAP_CLIENT_Y-dy-1); set_block(MAP_CLIENT_X-x-1, MAP_CLIENT_Y-y-1, MAP_CLIENT_X-dx-1, MAP_CLIENT_Y-dy-1); } } } } } } /** * This recursively sets the blocked line of sight view. * From the blocked[][] array, we know for example * that if some particular space is blocked, it blocks * the view of the spaces 'behind' it, and those blocked * spaces behind it may block other spaces, etc. * In this way, the chain of visibility is set. * Used to initialise the array used by the LOS routines. * * @param op * player for which we're computing. * @param x * @param y * indexes into the blocked[][] array. */ static void set_wall(object *op, int x, int y) { int i; for (i = 0; i < block[x][y].index; i++) { int dx = block[x][y].x[i], dy = block[x][y].y[i], ax, ay; /* ax, ay are the values as adjusted to be in the * socket look structure. */ ax = dx-(MAP_CLIENT_X-op->contr->socket.mapx)/2; ay = dy-(MAP_CLIENT_Y-op->contr->socket.mapy)/2; if (ax < 0 || ax >= op->contr->socket.mapx || ay < 0 || ay >= op->contr->socket.mapy) continue; /* we need to adjust to the fact that the socket * code wants the los to start from the 0,0 * and not be relative to middle of los array. */ op->contr->blocked_los[ax][ay] = 100; set_wall(op, dx, dy); } } /** * Used to initialise the array used by the LOS routines. * @param op * player's object * @param x * @param y * Values based on MAP_CLIENT_X and Y that index the blocked[][] arrays. * * @todo * use player *instead of object *to show it must be a player? */ static void check_wall(object *op, int x, int y) { int ax, ay; if (!block[x][y].index) return; /* ax, ay are coordinates as indexed into the look window */ ax = x-(MAP_CLIENT_X-op->contr->socket.mapx)/2; ay = y-(MAP_CLIENT_Y-op->contr->socket.mapy)/2; /* If the converted coordinates are outside the viewable * area for the client, return now. */ if (ax < 0 || ay < 0 || ax >= op->contr->socket.mapx || ay >= op->contr->socket.mapy) return; /* If this space is already blocked, prune the processing - presumably * whatever has set this space to be blocked has done the work and already * done the dependency chain. */ if (op->contr->blocked_los[ax][ay] == 100) return; if (get_map_flags(op->map, NULL, op->x+x-MAP_CLIENT_X/2, op->y+y-MAP_CLIENT_Y/2, NULL, NULL)&(P_BLOCKSVIEW|P_OUT_OF_MAP)) set_wall(op, x, y); } /** * Clears/initialises the los-array associated to the player * controlling the object. * * @param op * player's object. * * @todo * use player *instead of object *to show it must be a player? */ void clear_los(object *op) { /* This is safer than using the socket->mapx, mapy because * we index the blocked_los as a 2 way array, so clearing * the first z spaces may not not cover the spaces we are * actually going to use */ (void)memset((void *)op->contr->blocked_los, 0, MAP_CLIENT_X*MAP_CLIENT_Y); } /** * Goes through the array of what the given player is * able to see, and expands the visible area a bit, so the player will, * to a certain degree, be able to see into corners. * This is somewhat suboptimal, would be better to improve the formula. * * @param op * player's object to process. * * @todo * use player *instead of object *to show it must be a player? */ static void expand_sight(object *op) { int i, x, y, dx, dy; for (x = 1; x < op->contr->socket.mapx-1; x++) /* loop over inner squares */ for (y = 1; y < op->contr->socket.mapy-1; y++) { if (!op->contr->blocked_los[x][y] && !(get_map_flags(op->map, NULL, op->x-op->contr->socket.mapx/2+x, op->y-op->contr->socket.mapy/2+y, NULL, NULL)&(P_BLOCKSVIEW|P_OUT_OF_MAP))) { for (i = 1; i <= 8; i += 1) { /* mark all directions */ dx = x+freearr_x[i]; dy = y+freearr_y[i]; if (op->contr->blocked_los[dx][dy] > 0) /* for any square blocked */ op->contr->blocked_los[dx][dy] = -1; } } } if (MAP_DARKNESS(op->map) > 0) /* player is on a dark map */ expand_lighted_sight(op); /* clear mark squares */ for (x = 0; x < op->contr->socket.mapx; x++) for (y = 0; y < op->contr->socket.mapy; y++) if (op->contr->blocked_los[x][y] < 0) op->contr->blocked_los[x][y] = 0; } /** * Checks if op has a light source. * * @param op * object being checked. * @return * true if op carries one or more lights * * @note * This is a trivial function now days, but it used to * be a bit longer. Probably better for callers to just * check the op->glow_radius instead of calling this. */ int has_carried_lights(const object *op) { /* op may glow! */ if (op->glow_radius > 0) return 1; return 0; } /** * Propagate the light information. * * @param op * player's object for which to compute the light values. */ static void expand_lighted_sight(object *op) { int x, y, darklevel, ax, ay, basex, basey, mflags, light, x1, y1; mapstruct *m = op->map; sint16 nx, ny; darklevel = MAP_DARKNESS(m); /* If the player can see in the dark, lower the darklevel for him */ if (QUERY_FLAG(op, FLAG_SEE_IN_DARK)) darklevel -= 2; /* add light, by finding all (non-null) nearby light sources, then * mark those squares specially. If the darklevel<1, there is no * reason to do this, so we skip this function */ if (darklevel < 1) return; /* Do a sanity check. If not valid, some code below may do odd * things. */ if (darklevel > MAX_DARKNESS) { LOG(llevError, "Map darkness for %s on %s is too high (%d)\n", op->name, op->map->path, darklevel); darklevel = MAX_DARKNESS; } /* First, limit player furthest (unlighted) vision */ for (x = 0; x < op->contr->socket.mapx; x++) for (y = 0; y < op->contr->socket.mapy; y++) if (op->contr->blocked_los[x][y] != 100) op->contr->blocked_los[x][y] = MAX_LIGHT_RADII; /* the spaces[] darkness value contains the information we need. * Only process the area of interest. * the basex, basey values represent the position in the op->contr->blocked_los * array. Its easier to just increment them here (and start with the right * value) than to recalculate them down below. */ for (x = (op->x-op->contr->socket.mapx/2-MAX_LIGHT_RADII), basex = -MAX_LIGHT_RADII; x <= (op->x+op->contr->socket.mapx/2+MAX_LIGHT_RADII); x++, basex++) { for (y = (op->y-op->contr->socket.mapy/2-MAX_LIGHT_RADII), basey = -MAX_LIGHT_RADII; y <= (op->y+op->contr->socket.mapy/2+MAX_LIGHT_RADII); y++, basey++) { m = op->map; nx = x; ny = y; mflags = get_map_flags(m, &m, nx, ny, &nx, &ny); if (mflags&P_OUT_OF_MAP) continue; /* This space is providing light, so we need to brighten up the * spaces around here. */ light = GET_MAP_LIGHT(m, nx, ny); if (light != 0) { for (ax = basex-light; ax <= basex+light; ax++) { if (ax < 0 || ax >= op->contr->socket.mapx) continue; for (ay = basey-light; ay <= basey+light; ay++) { if (ay < 0 || ay >= op->contr->socket.mapy) continue; /* If the space is fully blocked, do nothing. Otherwise, we * brighten the space. The further the light is away from the * source (basex-x), the less effect it has. Though light used * to dim in a square manner, it now dims in a circular manner * using the the pythagorean theorem. glow_radius still * represents the radius */ if (op->contr->blocked_los[ax][ay] != 100) { x1 = abs(basex-ax)*abs(basex-ax); y1 = abs(basey-ay)*abs(basey-ay); if (light > 0) op->contr->blocked_los[ax][ay] -= MAX((light-isqrt(x1+y1)), 0); if (light < 0) op->contr->blocked_los[ax][ay] -= MIN((light+isqrt(x1+y1)), 0); } } /* for ay */ } /* for ax */ } /* if this space is providing light */ } /* for y */ } /* for x */ /* Outdoor should never really be completely pitch black dark like * a dungeon, so let the player at least see a little around themselves */ if (op->map->outdoor && darklevel > (MAX_DARKNESS-3)) { if (op->contr->blocked_los[op->contr->socket.mapx/2][op->contr->socket.mapy/2] > (MAX_DARKNESS-3)) op->contr->blocked_los[op->contr->socket.mapx/2][op->contr->socket.mapy/2] = MAX_DARKNESS-3; for (x = -1; x <= 1; x++) for (y = -1; y <= 1; y++) { if (op->contr->blocked_los[x+op->contr->socket.mapx/2][y+op->contr->socket.mapy/2] > (MAX_DARKNESS-2)) op->contr->blocked_los[x+op->contr->socket.mapx/2][y+op->contr->socket.mapy/2] = MAX_DARKNESS-2; } } /* grant some vision to the player, based on the darklevel */ for (x = darklevel-MAX_DARKNESS; x < MAX_DARKNESS+1-darklevel; x++) for (y = darklevel-MAX_DARKNESS; y < MAX_DARKNESS+1-darklevel; y++) if (!(op->contr->blocked_los[x+op->contr->socket.mapx/2][y+op->contr->socket.mapy/2] == 100)) op->contr->blocked_los[x+op->contr->socket.mapx/2][y+op->contr->socket.mapy/2] -= MAX(0, 6-darklevel-MAX(abs(x), abs(y))); } /** * Sets all veiwable squares to blocked except * for the one the central one that the player occupies. A little * odd that you can see yourself (and what your standing on), but * really need for any reasonable game play. * * @param op * player's object for which to reset los. Must have a valid contr. */ static void blinded_sight(object *op) { int x, y; for (x = 0; x < op->contr->socket.mapx; x++) for (y = 0; y < op->contr->socket.mapy; y++) op->contr->blocked_los[x][y] = 100; op->contr->blocked_los[op->contr->socket.mapx/2][op->contr->socket.mapy/2] = 0; } /** * Recalculates the array which specifies what is * visible for the given player-object. * * @param op * player's object for which to compute. */ void update_los(object *op) { int dx = op->contr->socket.mapx/2, dy = op->contr->socket.mapy/2, x, y; if (QUERY_FLAG(op, FLAG_REMOVED)) return; clear_los(op); if (QUERY_FLAG(op, FLAG_WIZ) /* || XRAYS(op) */) return; /* For larger maps, this is more efficient than the old way which * used the chaining of the block array. Since many space views could * be blocked by different spaces in front, this mean that a lot of spaces * could be examined multile times, as each path would be looked at. */ for (x = (MAP_CLIENT_X-op->contr->socket.mapx)/2+1; x < (MAP_CLIENT_X+op->contr->socket.mapx)/2-1; x++) for (y = (MAP_CLIENT_Y-op->contr->socket.mapy)/2+1; y < (MAP_CLIENT_Y+op->contr->socket.mapy)/2-1; y++) check_wall(op, x, y); /* do the los of the player. 3 (potential) cases */ if (QUERY_FLAG(op, FLAG_BLIND)) /* player is blind */ blinded_sight(op); else expand_sight(op); if (QUERY_FLAG(op, FLAG_XRAYS)) { int x, y; for (x = -2; x <= 2; x++) for (y = -2; y <= 2; y++) op->contr->blocked_los[dx+x][dy+y] = 0; } } /** * update all_map_los is like update_all_los() below, * but updates everyone on the map, no matter where they * are. This generally should not be used, as a per * specific map change doesn't make much sense when tiling * is considered (lowering darkness would certainly be a * strange effect if done on a tile map, as it makes * the distinction between maps much more obvious to the * players, which is should not be. * Currently, this function is called from the * change_map_light function * * @param map * map on which affected players are. */ void update_all_map_los(mapstruct *map) { player *pl; for (pl = first_player; pl != NULL; pl = pl->next) { if (pl->ob->map == map) pl->do_los = 1; } } /** * This function makes sure that update_los() will be called for all * players on the given map within the next frame. * It is triggered by removal or inserting of objects which blocks * the sight in the map. * Modified by MSW 2001-07-12 to take a coordinate of the changed * position, and to also take map tiling into account. This change * means that just being on the same map is not sufficient - the * space that changes must be withing your viewable area. * * @param map * map that changed. * @param x * @param y * coordinates of the change. * * @todo * check if this couldn't be simplified, especially tiling (isn't there a function somewhere that could help?) */ void update_all_los(const mapstruct *map, int x, int y) { player *pl; for (pl = first_player; pl != NULL; pl = pl->next) { /* Player should not have a null map, but do this * check as a safety */ if (!pl->ob->map) continue; /* Same map is simple case - see if pl is close enough. * Note in all cases, we did the check for same map first, * and then see if the player is close enough and update * los if that is the case. If the player is on the * corresponding map, but not close enough, then the * player can't be on another map that may be closer, * so by setting it up this way, we trim processing * some. */ if (pl->ob->map == map) { if ((abs(pl->ob->x-x) <= pl->socket.mapx/2) && (abs(pl->ob->y-y) <= pl->socket.mapy/2)) pl->do_los = 1; } /* Now we check to see if player is on adjacent * maps to the one that changed and also within * view. The tile_maps[] could be null, but in that * case it should never match the pl->ob->map, so * we want ever try to dereference any of the data in it. */ /* The logic for 0 and 3 is to see how far the player is * from the edge of the map (height/width) - pl->ob->(x,y) * and to add current position on this map - that gives a * distance. * For 1 and 2, we check to see how far the given * coordinate (x,y) is from the corresponding edge, * and then add the players location, which gives * a distance. */ else if (pl->ob->map == map->tile_map[0]) { if ((abs(pl->ob->x-x) <= pl->socket.mapx/2) && (abs(y+MAP_HEIGHT(map->tile_map[0])-pl->ob->y) <= pl->socket.mapy/2)) pl->do_los = 1; } else if (pl->ob->map == map->tile_map[2]) { if ((abs(pl->ob->x-x) <= pl->socket.mapx/2) && (abs(pl->ob->y+MAP_HEIGHT(map)-y) <= pl->socket.mapy/2)) pl->do_los = 1; } else if (pl->ob->map == map->tile_map[1]) { if ((abs(pl->ob->x+MAP_WIDTH(map)-x) <= pl->socket.mapx/2) && (abs(pl->ob->y-y) <= pl->socket.mapy/2)) pl->do_los = 1; } else if (pl->ob->map == map->tile_map[3]) { if ((abs(x+MAP_WIDTH(map->tile_map[3])-pl->ob->x) <= pl->socket.mapx/2) && (abs(pl->ob->y-y) <= pl->socket.mapy/2)) pl->do_los = 1; } } } /** * Debug-routine which dumps the array which specifies the visible * area of a player. Triggered by the DM command printlos. * * @param op * DM asking for information. * * @todo * change the command to view another player's LOS? */ void print_los(object *op) { int x, y; char buf[MAP_CLIENT_X*2+20], buf2[10]; snprintf(buf, sizeof(buf), "[fixed] "); for (x = 0; x < op->contr->socket.mapx; x++) { snprintf(buf2, sizeof(buf2), "%2d", x); strncat(buf, buf2, sizeof(buf)-strlen(buf)-1); } draw_ext_info(NDI_UNIQUE, 0, op, MSG_TYPE_COMMAND, MSG_TYPE_COMMAND_DEBUG, buf, NULL); for (y = 0; y < op->contr->socket.mapy; y++) { snprintf(buf, sizeof(buf), "[fixed]%2d:", y); for (x = 0; x < op->contr->socket.mapx; x++) { snprintf(buf2, sizeof(buf2), " %1d", op->contr->blocked_los[x][y] == 100 ? 1 : 0); strncat(buf, buf2, sizeof(buf)-strlen(buf)-1); } draw_ext_info(NDI_UNIQUE, 0, op, MSG_TYPE_COMMAND, MSG_TYPE_COMMAND_DEBUG, buf, NULL); } } /** * The object is supposed to be visible through walls, thus * check if any players are nearby, and edit their LOS array. * * @param op * object that should be visible. * * @todo * what about tiled maps? */ void make_sure_seen(const object *op) { player *pl; for (pl = first_player; pl; pl = pl->next) if (pl->ob->map == op->map && pl->ob->y-pl->socket.mapy/2 <= op->y && pl->ob->y+pl->socket.mapy/2 >= op->y && pl->ob->x-pl->socket.mapx/2 <= op->x && pl->ob->x+pl->socket.mapx/2 >= op->x) pl->blocked_los[pl->socket.mapx/2+op->x-pl->ob->x][pl->socket.mapy/2+op->y-pl->ob->y] = 0; } /** * The object which is supposed to be visible through * walls has just been removed from the map, so update the los of any * players within its range * * @param op * object that disappears. * * @todo * what about tiled maps? */ void make_sure_not_seen(const object *op) { player *pl; for (pl = first_player; pl; pl = pl->next) if (pl->ob->map == op->map && pl->ob->y-pl->socket.mapy/2 <= op->y && pl->ob->y+pl->socket.mapy/2 >= op->y && pl->ob->x-pl->socket.mapx/2 <= op->x && pl->ob->x+pl->socket.mapx/2 >= op->x) pl->do_los = 1; }