Onwaal

[cbk1994]

Can someone PLEASE help me with the onwall checks for a car? :C

I SUCK at onwall checks, I'm just doing

PHP Code:

function willCrash()
{
  temp.movex = getMoveX();
  temp.movey = getMoveY();
  
  if ( onwall2( temp.movex, temp.movey, 2, 2 ) )
  {
    return true;
  }
} 


can someone please help me with this?

I'm showing an image for the car, which simply rotates.

[JkWhoSaysNi]

The difficult part is detecting where it hits the car and calculating how the car should react (e.g. bounce off or come to a complete stop or just slow down but continue moving or whatever) depending on the angle it hits and the speed it's travelling.

Unless the car is small, using the X/Y co-ordinates will not work because probably that part of the car is not on the wall.

You need to detect ahead of the direction the car is moving and for the width of the car, or do multiple checks.

[DustyPorViva]

Depends, is your car only moving in four directions or is it capable of turning in a complete circle?

[JkWhoSaysNi]

Actually I have some code similar to what you're doing.

This was for an NPC:

PHP Code:

s1 = (onwall2(x+vecx(this.dir)+vecx(this.dir)-abs(vecy(this.dir)),y+vecy(this.dir)+vecy(this.dir)-abs(vecx(this.dir)),1,1)) ? 1: 0;
  s2 = (onwall2(x+vecx(this.dir)+vecx(this.dir)+abs(vecy(this.dir)*2),y+vecy(this.dir)+vecy(this.dir)+abs(vecx(this.dir)*2),1,1)) ? 1: 0; 


It puts 2 'sensors' in at the front of the NPC, then I had the NPC decide which way to turn based on the check.

It was actually a line follower which I tried (without success :P ) to develop into a maze solver.

The line follower code may actually help as a base for deciding what should happen depending on which 'sensor' has been hit.

PHP Code:

//Line follower

function onTimeout() {
 weights = {{1,0,-1},{1,-1,0}};
 output = {1,1};

  s1 = (onwall2(x+vecx(this.dir)+vecx(this.dir)-abs(vecy(this.dir)),y+vecy(this.dir)+vecy(this.dir)-abs(vecx(this.dir)),1,1)) ? 1: 0;
  s2 = (onwall2(x+vecx(this.dir)+vecx(this.dir)+abs(vecy(this.dir)*2),y+vecy(this.dir)+vecy(this.dir)+abs(vecx(this.dir)*2),1,1)) ? 1: 0;
  res1=weights[0][1]*s1+weights[0][2]*s2+weights[0][0];
  output[0] = (res1>0) ? 1 : 0;
  res2=weights[1][1]*s1+weights[1][2]*s2+weights[1][0];
  output[1] = (res2>0) ? 1 : 0;



   if ((output[0]==1)&&(output[1]==1))
    lturn(); //turn -45 degrees
   if ((output[0]==0)&&(output[1]==0))
    rturn(); //turn 45 degrees

   if ((output[0]==1)&&(output[1]==0))
    forward(); 
   if ((output[0]==0)&&(output[1]==1))
    back();


     setTimer(0.05);

} 


It actually uses a 2 neuron model (not really a neural net because it's just a 2 neuron model but it could be developed into one)

[DustyPorViva]

The key is to check the next possible movement, ahead of the NPC, as the 'current' placement of the NPC will usually be behind in consideration with the movement.
Also, if you have the car turning, what I did was do multiple checks along the front of the car, from say, the left bumper to the right. If there is any check that is onwall, stop the movement.

[JkWhoSaysNi]

Yeah, but just stopping will feel incredibly strange to anyone driving the car (depending on speed). If you drive 100mph into a wall at anything but head on you wouldn't just stop

Look at my crudely drawn attachment

Depending on the angle, the car will hit the wall and go front first into the wall (A) or the corner will slide along the wall and the left side of the car will get closer to the wall (B).

[cbk1994]

I'll just post my code... JKWhoSaysNi, thanks, but that won't work with full angles (I think?)

PHP Code:

//#CLIENTSIDE
function onCreated()
{
  this.speed = 2;
  this.car = false;
  setTimer( 0.05 );
}
function getMoveX()
{
  return player.x + ( this.mspeed * sin( this.ang ) );
}
function getMoveY()
{
  return player.y + ( this.mspeed * cos( this.ang ) );
}
function getMoveDX()
{
  return player.x + ( 1 * sin( this.ang ) );
}
function getMoveDY()
{
  return player.y + ( 1 * cos( this.ang ) );
}
function willCrash()
{
  temp.movex = getMoveX();
  temp.movey = getMoveY();
  
  if ( onwall( temp.movex, temp.movey ) )
  {
    return true;
  }
  if ( onwall( temp.movex + 1, temp.movey ) )
  {
    return true;
  }
  if ( onwall( temp.movex - 1, temp.movey ) )
  {
    return true;
  }
  if ( onwall( temp.movex, temp.movey + 1 ) )
  {
    return true;
  }
  if ( onwall( temp.movex, temp.movey - 1 ) )
  {
    return true;
  }
  
  if ( onwall( temp.movex + 3, temp.movey ) )
  {
    return true;
  }
  if ( onwall( temp.movex - 2, temp.movey ) )
  {
    return true;
  }
  if ( onwall( temp.movex, temp.movey + 2 ) )
  {
    return true;
  }
  if ( onwall( temp.movex, temp.movey - 2 ) )
  {
    return true;
  }
}
function doHonk()
{
  player.attr[8] = "eb_sound-honk.gani";
  scheduleevent( .2, "ClearHorn", "" );
}
function newCheck()
{
  temp.movex = getMoveX();
  temp.movey = getMoveY();
  s1 = ( onwall2( temp.movex, temp.movey - abs(vecx(this.dir)),1,1)) ? 1: 0;
  s2 = ( onwall2( temp.movey, y+vecy(this.dir)+vecy(this.dir)+abs(vecx(this.dir)*2),1,1)) ? 1: 0;
}
function onClearHorn()
{
  player.attr[8] = "";
}
function setDir()
{
  temp.movex = getMoveDX();
  temp.movey = getMoveDY();
  player.dir = getdir( temp.movex - player.x, temp.movey - player.y );
}
function checkCar()
{
  player.attr[7] = this.ang;
  client.car_angle = this.ang;
  setAni( "sit", NULL );
  disabledefmovement();
  temp.movex = getMoveX();
  temp.movey = getMoveY();
  
  if ( keydown( 1 ) )
  {
    this.ang += .1;
    setDir();
  }
  if ( keydown( 3 ) )
  {
    this.ang -= .1;
    setDir();
  }
  if ( keydown2( 32, true ) )
  {
    doHonk();
  }
  if ( keydown( 2 ) )
  {
    if ( this.mspeed > -1 )
    {
      this.mspeed -= .2;
    }
  }

  if ( keydown( 0 ) )
  {
    if ( this.mspeed < this.speed )
    {
      this.mspeed += .05;
    }
  }
  else
  {
    if ( this.mspeed > 0 )
    {
      this.mspeed -= .1;
      if ( this.mspeed < 0 )
      {
        this.mspeed = 0;
      }
    }
    if ( this.mspeed < 0 )
    {
      this.mspeed += .1;
      if ( this.mspeed > 0 )
      {
        this.mspeed = 0;
      }
    }
  }
  temp.movex = getMoveX();
  temp.movey = getMoveY();
  if ( willCrash() == false )
  {
    player.x = temp.movex;
    player.y = temp.movey;
  }
  else
  {
    this.mspeed = - .5;
  }
  //player.chat = "Speed:" SPC this.mspeed;
  //player.chat = format( "Angle: %s Move X: %s Move Y: %s", this.ang, temp.movex, temp.movey );
}
function onTimeOut()
{
  if ( this.car == true )
  {
    checkCar();
    player.attr[6] = "eb_car.gani";
  }
  else
  {
    player.attr[6] = "";
    enabledefmovement();
  }
  setTimer( 0.05 );
}
function onPlayerChats()
{
  if ( player.chat == "/car on" )
  {
    this.car = true;
  }
  if ( player.chat == "/car off" )
  {
    this.car = false;
  }
} 


That's not what the car will be like in the end, I just need the basic moving, turning, wall checking.

[JkWhoSaysNi]

Originally Posted by cbkbud

I'll just post my code... JKWhoSaysNi, thanks, but that won't work with full angles (I think?)

That's not what the car will be like in the end, I just need the basic moving, turning, wall checking.

That should work. You have the right idea at least, checking the next place the car is going to move.

What's wrong with it at the moment?

[DustyPorViva]

Originally Posted by JkWhoSaysNi

Yeah, but just stopping will feel incredibly strange to anyone driving the car (depending on speed). If you drive 100mph into a wall at anything but head on you wouldn't just stop

Look at my crudely drawn attachment

Depending on the angle, the car will hit the wall and go front first into the wall (A) or the corner will slide along the wall and the left side of the car will get closer to the wall (B).

Just have the car blow up.

[cbk1994]

Get on Tales and try it ... The server Tales, I'm on now. You can see for yourself.

[zokemon]

onwall2() might have been fixed up a little better but otherwise, I suggest onwall() personnally as I have always found it to be way more accurate in my wall checks.

[xAndrewx]

function getMove(playersPosition) 
{ 
  return player.(@ temp.playersPosition) + ( this.mspeed * sin( this.ang ) ); 
} 
function getMoveD(playersPosition) 
{ 
  return player.(@ temp.playersPosition) + ( 1 * sin( this.ang ) ); 
}

Easier...

[cbk1994]

Originally Posted by xAndrewx

function getMove(playersPosition) 
{ 
  return player.(@ temp.playersPosition) + ( this.mspeed * sin( this.ang ) ); 
} 
function getMoveD(playersPosition) 
{ 
  return player.(@ temp.playersPosition) + ( 1 * sin( this.ang ) ); 
}

Easier...

Which is almost exactly what I did o.O

[Kristi]

Originally Posted by zokemon

onwall2() might have been fixed up a little better but otherwise, I suggest onwall() personnally as I have always found it to be way more accurate in my wall checks.

there is nothing wrong with onwall2 if used correctly, and its less strain on the system

[Admins]

Originally Posted by zokemon

onwall2() might have been fixed up a little better but otherwise, I suggest onwall() personnally as I have always found it to be way more accurate in my wall checks.

onwall2() should always work fine, both are doing pixel-accurate checks on clientside and image-rectangle check on server, or checking the covered tiles.
For car movement it can be better to use onwall() though, since you need to do several checks to detect how you are touching the wall. It is especially quite some work to detect diagonal walls like on Zone, it is working most of the time but when the bike is fast it is getting harder since doing pixel-accurate checks on the whole shape of the bike is too slow.