ApplyVelocity()

  function ApplyVelocity(VelocityX, VelocityY) {
    OldStandingOnSolid = StandingOnSolid;
    StandingOnSolid = false;
    SideBlocked = false;

    local OldPosX = PosX, OldPosY = PosY;

    // check against touching stuff
    if(VelocityX > 0) {
      if(!lib.ChkBlockFlagXY(((PosX+VelocityX)>>8)+Width-1, (PosY>>8) + (Height/2), BlockFlags.SolidMiddle)
      && !lib.ChkBlockFlagXY(((PosX+VelocityX)>>8)+Width-1, (PosY>>8) + (Height-1), BlockFlags.SolidMiddle)
      && !lib.ChkBlockFlagXY(((PosX+VelocityX)>>8)+Width-1, (PosY>>8), BlockFlags.SolidMiddle))
        PosX += VelocityX;
      else {
        PosX = (((PosX+VelocityX)+(Width-1<<8)) & ~0xfff) - (16<<8);
        SideBlocked = true;
      }
    } else {
      if(!lib.ChkBlockFlagXY((PosX+VelocityX)>>8, (PosY>>8) + (Height/2), BlockFlags.SolidMiddle)
      && !lib.ChkBlockFlagXY((PosX+VelocityX)>>8, (PosY>>8) + (Height-1), BlockFlags.SolidMiddle)
      && !lib.ChkBlockFlagXY((PosX+VelocityX)>>8, (PosY>>8), BlockFlags.SolidMiddle))
        PosX += VelocityX;
      else {
        PosX = ((PosX-VelocityX) & ~0xfff);
        SideBlocked = true;
      }
    }

    // check for solids above
    if(lib.ChkBlockFlagXY((PosX>>8), (PosY>>8), BlockFlags.SolidMiddle)
    || lib.ChkBlockFlagXY((PosX>>8)+(Width-1), (PosY>>8), BlockFlags.SolidMiddle)) {
      VelY = 0x0f0;
    } else {
    }
    PosY += VelocityY;

    // check for flat floor (best kind)
    if(lib.ChkBlockFlagXY((PosX>>8), (PosY>>8) + Height, BlockFlags.SolidTop)
    || lib.ChkBlockFlagXY((PosX>>8)+(Width-1), (PosY>>8) + Height, BlockFlags.SolidTop)) {
      local CanFallLeft = lib.ChkBlockFlagXY((PosX>>8), (PosY>>8) + Height, BlockFlags.FallThrough);
      local CanFallRight = lib.ChkBlockFlagXY((PosX>>8) + Width - 1, (PosY>>8) + Height, BlockFlags.FallThrough);
      if((VelocityY >= 0 && ((((PosY>>8) + Height) >>4) != (((OldPosY>>8) + Height - 1)>>4)))
      && !(WillFallThrough && CanFallLeft && CanFallRight)) {
        PosY = ((PosY+(Height<<8)) & 0xf000)-(Height<<8);
        VelY = 0;
        StandingOnSolid = true;
      }
    }

    // slopes mostly fixed but still a bit buggy
    if(lib.ChkBlockFlagXY((PosX>>8)+(Width-1), (PosY>>8)+Height-1, BlockFlags.SlopeL) && VelocityY >= 0) {
      local PartX = ((PosX>>8)+(Width-1))&15, PartY = ((PosY>>8)+(Height-1))&15, MaxY = 15-PartX;
      if(PartY>MaxY) PosY = (((((PosY>>8)+Height-1) & ~15)) - Height + MaxY) <<8;
      StandingOnSolid = true;
    }
    if(lib.ChkBlockFlagXY((PosX>>8), (PosY>>8)+Height-1, BlockFlags.SlopeR) && VelocityY >= 0) {
      local PartX = (PosX>>8)&15, PartY = ((PosY>>8)+(Height-1))&15, MaxY = PartX;
      if(PartY>MaxY) PosY = (((((PosY>>8)+Height-1) & ~15)) - Height + MaxY) <<8;
      StandingOnSolid = true;
    }

    if(lib.ChkBlockType((PosX>>8), (PosY>>8) + Height - 1, 23)
    || lib.ChkBlockType((PosX>>8)+(Width-1), (PosY>>8) + Height - 1, 23)) {
       VelY = -0x0500;
    }

  }
};