DieHard Wolfers

[Metalor]

I'm currently trying to add a player blocking object into one of my projects, but the compiler doesn't like the code string I put into it, giving me the message: "error: ISO C++ forbids cast to non-reference type used as lvalue"

This is the code I've been trying to implement:

::: CODE :::

    statobj_t   *statptr;

...

    if (*(mapsegs[1] + offset) == BLOCKPLAYER)
    {
        (unsigned)actorat[statptr->tilex][statptr->tiley] = 1;
    }

I'm pretty certain the compiler doesn't like this code because it's specifically for old C compilers, and not C++. Any ideas?

[Tricob]

I'm pretty sure that changing the "actorat" structure isn't the right move. Instead, I'd use the ClipMove routine in WL_AGENT.CPP. Look for this code:

::: CODE :::

    if (TryMove (ob))
        return;

In this area, I'd expand the "if" statement so the Objects plane for the BLOCKPLAYER mark is detected.

[Metalor]

Okay, so then, how do I do that?

I've heard the objects plane thingy mentioned elsewhere, but I'd need an example to understand exactly what you mean (I'm sorry, I've been working on this stuff all day, so my brain's fried).

[Tricob]

I believe the code in WL_AGENT.CPP is this:

::: CODE :::

    if (TryMove (ob) || (*(mapsegs[1] + offset) == BLOCKPLAYER) )
        return;

As for WL_ACT1.CPP and WL_GAME.CPP, there should be no code referring to this "object" at all. The blocker I'm using is not an "Object" of any type. It's an invisible "checkmark" placed on the map, and it bars the player's way, should he try to cross it. MCS's "enemy-blocker code" works much the same way, so it isn't really my own original idea.

Please let me know if the code works. Thanks.

[Metalor]

Alright, I placed it at the bottom of TryMove(), and got these two errors:

error: `offset' was not declared in this scope
error: return-statement with no value, in function returning 'int'

Also, I knew that the "thing" being spawned was not an object, I'm just not familiar with creating things that refer to the objects plane.

[Tricob]

Metalor wrote:

Alright, I placed it at the bottom of TryMove(), and got these two errors:

Ah ... it should be in the ClipMove routine, and it should *replace* the TryMove lines of code, not just be inserted below it.

Regarding the "offset" error, try placing this line of code just above the TryMove line of code:

::: CODE :::

    offset = (player->tiley<<mapshift)+(player->tilex);

I believe that will cover it.

[Metalor]

I replaced all three instances of TryMove in ClipMove, and I added the "offset" code. The game didn't initially like that code, so I added:

::: CODE :::

unsigned    offset;

to make up for it.

However, the code doesn't seem to function properly, as I can still move over the space marked by the blocker in an editor, however it seems to have an odd effect when placed near walls as it makes it possible to enter into the nearby wall and get stuck inside.

To elaborate, I placed the strings under these three sets of code:

::: CODE :::

    ob->x = basex+xmove;
    ob->y = basey+ymove;

...

    ob->x = basex+xmove;
    ob->y = basey;

...

    ob->x = basex;
    ob->y = basey+ymove;

[Tricob]

The ClipMove routine should look like this:

::: CODE :::

void ClipMove (objtype *ob, int32_t xmove, int32_t ymove)
{
    int32_t    basex,basey;

    basex = ob->x;
    basey = ob->y;

    ob->x = basex+xmove;
    ob->y = basey+ymove;
    offset = (player->tiley<<mapshift)+(player->tilex);
    if (TryMove (ob) || (*(mapsegs[1] + offset) == BLOCKPLAYER) )
        return;

#ifndef REMDEBUG
    if (noclip && ob->x > 2*TILEGLOBAL && ob->y > 2*TILEGLOBAL
        && ob->x < (((int32_t)(mapwidth-1))<<TILESHIFT)
        && ob->y < (((int32_t)(mapheight-1))<<TILESHIFT) )
        return;         // walk through walls
#endif

    if (!SD_SoundPlaying() ) SD_PlaySound (HITWALLSND);

    ob->x = basex+xmove;
    ob->y = basey;
    if (TryMove (ob))
        return;

    ob->x = basex;
    ob->y = basey+ymove;
    if (TryMove (ob))
        return;

    ob->x = basex;
    ob->y = basey;
}

[Metalor]

Well, I made the changes above and it still seems to do the same thing. In fact, the only thing the spaces seem to do is the opposite of what I'm trying to program them to do (I've gotten stuck inside of both walls and enemies now).

I'm not real keen on how this code works, but I'd assume it'd have something with playerobj in it or something to prevent the player entering inside. At least, that's what I'd guess off the top of my head.

[Chris]

I think Tricob's idea might work if you arrange it something like this...

::: CODE :::

boolean TryMove (objtype *ob)
{
    int         xl,yl,xh,yh,x,y;
    objtype    *check;
    int32_t     deltax,deltay;

    if (MAPSPOT(ob->x>>TILESHIFT, ob->y>>TILESHIFT, 1) == BLOCKPLAYER)
        return false;

    xl = (ob->x-PLAYERSIZE) >>TILESHIFT;
    yl = (ob->y-PLAYERSIZE) >>TILESHIFT;

[Metalor]

Tried Chris' code and it worked perfectly. Thanks for both of your help!

[Tricob]

Thanks for the helping hand, Chris.