Correct way to handle Vectors

xerox8521 · **Author**

Hi,

so been trying to get into SM extensions so far everything i made worked. Now i wanted to create a simple GetWeaponShootPosition native which takes a client and returns a float array. I got that setup but it seems im doing something wrong because it crashes right away. Looking through the source sdk 2013 code the function Weapon_ShootPosition seem to return a vector. So im not sure how i would handle the vector correctly as pointer or normal variable because the function itself doesn't return a vector pointer.

PHP Code:


			
cell_t Native_GetWeaponShootPosition(IPluginContext *pContext, const cell_t *params)
{
    static ICallWrapper *pWrapper = NULL;
    if(!pWrapper)
    {
        REGISTER_NATIVE_ADDR("CBasePlayer::Weapon_ShootPosition",
            PassInfo pass[1]; \
            PassInfo ret;\
            pass[0].flags = PASSFLAG_BYVAL; \
            pass[0].size = sizeof(CBaseEntity *); \
            pass[0].type = PassType_Basic; \
            
            ret.flags = PASSFLAG_BYVAL;\
            ret.size = sizeof(Vector);\
            ret.type = PassType_Basic;\
            pWrapper = g_pBinTools->CreateCall(addr, CallConv_ThisCall, &ret, pass, 1));
    }
    CBaseEntity *pEntity;
    if(!(pEntity = GetCBaseEntity(params[1], true)))
    {
        return pContext->ThrowNativeError("Client index %d is invalid",params[1]);
    }
    
    cell_t *pPos;
    pContext->LocalToPhysAddr(params[2], &pPos);
    
    unsigned char vstk[sizeof(CBaseEntity *)];
    unsigned char *vptr = vstk;
    
    *(CBaseEntity **)vptr = pEntity;
    vptr +=sizeof(CBaseEntity *);
    Vector pos;
    pWrapper->Execute(vstk, &pos);
    
    pPos[0] = sp_ftoc(pos.x);
    pPos[1] = sp_ftoc(pos.y);
    pPos[2] = sp_ftoc(pos.z);
    return 1;
}

psychonic · *Last edited by psychonic; 03-12-2016 at 09:07.*

While this doesn't answer your question, you can just call GetClientEyePosition in SM to get the same Vector, rather than needing to create an extension for it. Most or all games use the eye position at the shoot position unless the client is in a vehicle.

(Eyeballing it, I don't see the issue with your code however)

donrevan · *Last edited by donrevan; 03-13-2016 at 07:40.*

You can try calling it via a typedef to see if it is working.

Code:

typedef Vector (__thiscall *tGetShootPos)(CBasePlayer*);
tGetShootPos shootPos = (tGetShootPos)addr;
Vector vec = shootPos(pPlayer);

Isn't Weapon_ShootPosition virtual? You don't need a signature scan to call it. Maybe you're accidently calling the wrong function(wrong signature?)

xerox8521 · 03-13-2016 , 16:13 Re: Correct way to handle Vectors

Ok so i have rebuild this with SM using this signature (@_ZN11CBasePlayer20Weapon_ShootPositionEv) game is Zombie Panic Source. Both versions work the virtual and Signature thing.

PHP Code:


			
    StartPrepSDKCall(SDKCall_Player);
    PrepSDKCall_SetFromConf(conf,SDKConf_Virtual,"CBasePlayer::Weapon_ShootPosition");
    //PrepSDKCall_SetFromConf(conf,SDKConf_Signature,"CBasePlayer::Weapon_ShootPosition");
    PrepSDKCall_SetReturnInfo(SDKType_Vector,SDKPass_ByValue);
    hWeaponGetShootPosition = EndPrepSDKCall();

and this works. So i dont really understand why the extension version does not work. Btw the extension does some function detouring also im trying to get into sm extensions

donrevan · *Last edited by donrevan; 03-14-2016 at 06:09.*

Quote:

Originally Posted by xerox8521

So i dont really understand why the extension version does not work. Btw the extension does some function detouring also im trying to get into sm extensions

ptr +=sizeof(CBaseEntity *);
is unnecessary(as you dont have any other param) but doesn't cause the crash.

pWrapper = g_pBinTools->CreateCall(addr, CallConv_ThisCall, &ret, pass, 1));
You pass 1 as paramcount but Weapon_ShootPosition doesn't have any parameters(thisptr is implicit). See the documentation..
This means you don't need to pass pass either. Try this instead:
pWrapper = g_pBinTools->CreateCall(addr, CallConv_ThisCall, &ret, NULL, 0));

xerox8521 · *Last edited by xerox8521; 03-18-2016 at 12:46.*

NVM. did it differently using sourcepawn now.

Hm yea tried that but doesn't seem to work either.

PHP Code:


			
cell_t Native_GetWeaponShootPosition(IPluginContext *pContext, const cell_t *params)
{
    static ICallWrapper *pWrapper = NULL;
    if(!pWrapper)
    {
        REGISTER_NATIVE_ADDR("CBasePlayer::Weapon_ShootPosition",
        
            PassInfo ret;\
            
            ret.flags = PASSFLAG_BYVAL;\
            ret.size = sizeof(Vector);\
            ret.type = PassType_Basic;\
            pWrapper = g_pBinTools->CreateCall(addr, CallConv_ThisCall, &ret, NULL, 0));
    }
    CBaseEntity *pEntity;
    if(!(pEntity = GetCBaseEntity(params[1], true)))
    {
        return pContext->ThrowNativeError("Client index %d is invalid",params[1]);
    }
    
    cell_t *pPos;
    pContext->LocalToPhysAddr(params[2], &pPos);
    
    unsigned char vstk[sizeof(CBaseEntity *)];
    unsigned char *vptr = vstk;
    
    *(CBaseEntity **)vptr = pEntity;
    //vptr +=sizeof(CBaseEntity *);
    Vector pos;
    pWrapper->Execute(vstk, &pos);
    
    pPos[0] = sp_ftoc(pos.x);
    pPos[1] = sp_ftoc(pos.y);
    pPos[2] = sp_ftoc(pos.z);
    return 1;
}