tiled movement

toshiro · **Joined:** Thu Apr 01, 2010 4:25 am **Posts:** 8

hello i need a little help with moving a character in a tiled system, my character should move 50 pixels after i press right button, it does but sometimes it moves all the time and i cant stop it sometimes it moves 53 pixels..

ok my Update function:

Code:

void Player::Update( float deltaTime )
{
   switch( m_playerState )
   {
   case PLAYER_IDLE:
      break;

   case PLAYER_WALK:
      position_x += ( velocity_x * deltaTime );
      position_y += ( velocity_y * deltaTime );

      break;
   }
}

a think function:

Code:

void Player::Think( void )
{
   if( std::abs( position_x - destination_x ) < 0.001f && std::abs( position_y - destination_y ) < 0.001f )
   {
      m_playerState = PLAYER_IDLE;
   }

}

OnWalk function:

Code:

void Player::Update( float deltaTime )
{
   switch( m_playerState )
   {
   case PLAYER_IDLE:
      break;

   case PLAYER_WALK:
      position_x += ( velocity_x * deltaTime );
      position_y += ( velocity_y * deltaTime );

      break;
   }
}

void Player::InputEvents( void )
{
   switch( m_playerState )
   {
   case PLAYER_IDLE:
      switch( Globals::event.key.keysym.sym )
      {
      case SDLK_UP:
         OnWalk( NORTH );
         break;

      case SDLK_DOWN:
         OnWalk( SOUTH );
         break;

      case SDLK_RIGHT:
         OnWalk( EAST );
         break;

      case SDLK_LEFT:
         OnWalk( WEST );
         break;
      }

   case PLAYER_WALK:
      break;
   }
}

void Player::Think( void )
{
   if( std::abs( position_x - destination_x ) < 0.001f && std::abs( position_y - destination_y ) < 0.001f )
   {
      m_playerState = PLAYER_IDLE;
   }

}

void Player::Draw( void )
{
   m_sprite->Draw( static_cast<int>( position_x ), static_cast<int>( position_y ) );
}

bool Player::OnWalk( direction_t direction )
{
   if( PlayerIsStanding() )
   {
      m_playerState = PLAYER_WALK;

      switch( direction )
      {
      case NORTH:
         destination_x = position_x;
         destination_y = position_y - 50.0f;

         velocity_x = 0;
         velocity_y = -m_movementSpeed;
         break;

      case SOUTH:
         destination_x = position_x;
         destination_y = position_y + 50.0f;

         velocity_x = 0;
         velocity_y = m_movementSpeed;
         break;

      case EAST:
         destination_x = position_x + 50.0f;
         destination_y = position_y;

         velocity_x = m_movementSpeed;
         velocity_y = 0;
         break;

      case WEST:
         destination_x = position_x - 50.0f;
         destination_y = position_y;

         velocity_x = -m_movementSpeed;
         velocity_y = 0;
         break;

         return true;
      }
   }

   return false;
}

Tim · **Posted:** Thu Jul 15, 2010 8:28 am

A simple fix would be to know where the entity is trying to go, and then to detect the proximity to that destination. If they are close, then stop all movement, and fixate them at those exact coords. Other than that, you simple have to time the movement right.

toshiro · **Joined:** Thu Apr 01, 2010 4:25 am **Posts:** 8

i am going to check it out:

Code:

void Player::Think( void )
{
   switch( m_playerState )
   {
   case PLAYER_IDLE:
      break;

   case PLAYER_WALK:
      /*if( std::abs( position_x - destination_x ) <= 0.001f && std::abs( position_y - destination_y ) <= 0.001f )
      {
         velocity_x = 0;
         velocity_y = 0;
         m_playerState = PLAYER_IDLE;
      }*/

      switch( m_movementDirection )
      {
      case EAST:
         if( position_x >= destination_x )
         {
            position_x = destination_x;
            position_y = destination_y;
            velocity_x = 0.0f;
            velocity_y = 0.0f;
            m_playerState = PLAYER_IDLE;
         }

         break;
      }

      break;
   }

}

i think that it works and the part with std::abs was somehow bugged or not well written

tiled movement

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