Wall following script

[Dan Furst]

Hi guys,

This script allows a freeform combo to follow the contours of a wall, or any other solid construct. The movement pattern is the same as the Sparks in Mario 2, if know what I mean. The ff combos are capable of following dynamic walkability patterns, and have a variety of speeds. You can have as many combos on the screen as ZQuest allows.

In this example quest, I made the combos damage type and they look like traps. (The cheat is "4" if you are impatient or can't get through.) I developed and tested this quest under 311.

wallflower.qst

Note you must pass in the ffc number, the pattern, the attachment, and the speed.

ffc script wallflower {

// PATTERN: The direction that the ffc will move initially.

// Up    = 1
// Down  = 2
// Left  = 3
// Right = 4


// ATTACHED: Specify the side of the ffc which is attached to the wall initially.

// Top       = 1
// Bottom    = 2
// Left      = 3
// Right     = 4
// TL corner = 5
// TR corner = 6
// BL corner = 7
// BR corner = 8


// SPEED: The speed must be one of the following values:
// 16, 8, 4, 2, 1, 0.5, 0.25, 0.125, 0.0625


void run(int this_ffc_num, int pattern, int attached, float speed)
{
	// "this_ffc->" bug workaround
	ffc this_ffc = Screen->LoadFFC(this_ffc_num);

	//if I'm stuck or floating
	if(!is_walkable(this_ffc->X, this_ffc->Y))
	{
		//I'm on a solid combo
		Quit();
	}
	if(is_walkable(this_ffc->X, this_ffc->Y - 16) && is_walkable(this_ffc->X, this_ffc->Y + 16) &&
		is_walkable(this_ffc->X - 16, this_ffc->Y) && is_walkable(this_ffc->X + 16, this_ffc->Y) &&
		is_walkable(this_ffc->X - 16, this_ffc->Y - 16) && is_walkable(this_ffc->X + 16, this_ffc->Y - 16) &&
		is_walkable(this_ffc->X - 16, this_ffc->Y + 16) && is_walkable(this_ffc->X + 16, this_ffc->Y + 16))
	{
		//I'm not near any wall
		Quit();
	}

	//the first move
	int dir = 0;
	dir = first_move(this_ffc->X, this_ffc->Y, pattern, attached);

	while(true) // main loop
	{
		if(dir == 1)
		{
			//up
			this_ffc->Vx = 0;
			this_ffc->Vy = -speed;
		}
		else if(dir == 2)
		{
			//down
			this_ffc->Vx = 0;
			this_ffc->Vy = speed;
		}
		else if(dir == 3)
		{
			//left
			this_ffc->Vx = -speed;
			this_ffc->Vy = 0;
		}
		else if(dir == 4)
		{
			//right
			this_ffc->Vx = speed;
			this_ffc->Vy = 0;
		}
		else
		{
			Quit();
		}

		// only do whole combos
		for(int i=0; i<(16/speed); i++)
		{
			Waitframe();
		}
		
		// see if the direction needs to be changed
		if(dir == 1) // was moving up
		{
			if(attached == 3) // L
			{
				if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 7; //BL
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 3; // L
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 1; // T
				}
				else // D
				{
					dir = 2; // D
					attached = 4; // R
				}
			}
			else if(attached == 4) // R
			{
				if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 8; //BR
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 4; // R
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 1; // T
				}
				else // D
				{
					dir = 2; // D
					attached = 3; // L
				}
			}
			else if(attached == 5) // TL
			{
				if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 3; // L
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 1; // T
				}
				else // D
				{
					dir = 2; // D
					attached = 4; // R
				}
			}
			else if(attached == 6) // TR
			{
				if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 4; // R
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 1; // T
				}
				else // D
				{
					dir = 2; // D
					attached = 3; // L
				}
			}
			else
			{
				Quit();
			}
		}
		if(dir == 2) // was moving down
		{
			if(attached == 3) // L
			{
				if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 5; //TL
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 3; // L
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 2; // B
				}
				else // U
				{
					dir = 1; // U
					attached = 4; // R
				}
			}
			else if(attached == 4) // R
			{
				if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 6; //TR
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 4; // R
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 2; // B
				}
				else // U
				{
					dir = 1; // U
					attached = 3; // L
				}
			}
			else if(attached == 7) // BL
			{
				if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 3; // L
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 2; // B
				}
				else // U
				{
					dir = 1; // U
					attached = 4; // R
				}
			}
			else if(attached == 8) // BR
			{
				if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 4; // R
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 2; // B
				}
				else // U
				{
					dir = 1; // U
					attached = 3; // L
				}
			}
			else
			{
				Quit();
			}
		}
		if(dir == 3) // was moving left
		{
			if(attached == 1) // T
			{
				if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 6; // TR
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 1; // T
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 3; // L
				}
				else
				{
					dir = 4; // R
					attached = 2; // B
				}
			}
			else if(attached == 2) // B
			{
				if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 8; // BR
				}
				else if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 2; // B
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 3; // L
				}
				else
				{
					dir = 4; // R
					attached = 1; // T
				}
			}
			else if(attached == 5) // TL
			{
				if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 1; // T
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 3; // L
				}
				else // R
				{
					dir = 4; // R
					attached = 2; // B
				}
			}
			else if(attached == 7) // BL
			{
				if(is_walkable(this_ffc->X - 16, this_ffc->Y)) // L
				{
					dir = 3; // L
					attached = 2; // B
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 3; // L
				}
				else // R
				{
					dir = 4; // R
					attached = 1; // T
				}
			}
			else
			{
				Quit();
			}
		}
		if(dir == 4) // was moving right
		{
			if(attached == 1) // T
			{
				if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 5; // TL
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 1; // T
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 4; // R
				}
				else
				{
					dir = 3; // L
					attached = 2; // B
				}
			}
			else if(attached == 2) // B
			{
				if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 7; // BL
				}
				else if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 2; // B
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 4; // R
				}
				else
				{
					dir = 3; // L
					attached = 1; // T
				}
			}
			else if(attached == 6) // TR
			{
				if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 1; // T
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y + 16)) // D
				{
					dir = 2; // D
					attached = 4; // R
				}
				else // L
				{
					dir = 3; // L
					attached = 2; // B
				}
			}
			else if(attached == 8) // BR
			{
				if(is_walkable(this_ffc->X + 16, this_ffc->Y)) // R
				{
					dir = 4; // R
					attached = 2; // B
				}
				else if(is_walkable(this_ffc->X, this_ffc->Y - 16)) // U
				{
					dir = 1; // U
					attached = 4; // R
				}
				else // L
				{
					dir = 3; // L
					attached = 1; // T
				}
			}
			else
			{
				Quit();
			}
		}
	}// end while true
}

int first_move(int x, int y, int pattern, int attached)
{
	if(pattern == 1)
	{
		//if up is walkable && not attached by B, BL, BR
		if(is_walkable(x, y - 16) && attached != 2 && attached != 7 && attached != 8)
		{    
			return 1;
		}
		return 0;
	}
	else if(pattern == 2)
	{
		//if down is walkable && not attached by T, TL, TR
		if(is_walkable(x, y + 16) && attached != 1 && attached != 5 && attached != 6)
		{
			return 2;
		}
		return 0;
	}
	else if(pattern == 3)
	{
		//if left is walkable && not attached by R, TR, BR
		if(is_walkable(x - 16, y) && attached != 4 && attached != 6 && attached != 8)
		{
			return 3;
		}
		return 0;
	}
	else if(pattern == 4)
	{
		//if right is walkable && not attached by L, TL, BL
		if(is_walkable(x + 16, y) && attached != 3 && attached != 5 && attached != 7)
		{
			return 4;
		}
		return 0;
	}
	else
	{
		//you entered an invalid pattern
		Quit();
	}
}

bool is_walkable(int x, int y)
{
	if(x<0 || x>240 || y<0 || y>160)
	{
		return false;
	}

	return Screen->ComboS[y+(x>>4)]==0;
}

}//end

So how do you like my first script?

[C-Dawg]

Here comes a new challanger!

Excellent work. This script, and your ice block script, are both behaviors I tried to get scripted up a few months back and wasn't able to complete. Awesome job on creating a working script! I hope this isn't the last we'll see from ya.

[Dan Furst]

I owe (at least a little) credit to you C-Dawg. I saw your attempted wall hugger script and got inspiration. I also stole your is_walkable function; hope you don't mind.


Wouldn't this script be cool to use in sideview, with jumping?

[C-Dawg]

Yep. I've already been using spark enemies, but so far they've been hard-coded using FFC changers. This will make them easier to apply to strangely shaped surfaces.

Oh, and no credit to me for the is_walkable function. That came from... whatshisface... the fellow with Sonic the Hedgehog holding a gun as his avatar...

[Pheonix]

Problem: when I try to import the script, it says (this is directly from the error box) "Unable to parse instruction 1 from script wallflower.t The error was: invalid intstruction. The command was (script)(wallflower,()"
Can someone help me?

[Dan Furst]

First, the file should have a .z extension.

You went to Tools -> Scripts -> Import ASM FFC Script, right? You don't want to do that. This is not ZASM, it's a ZScript. You want Tools -> Scripts -> Compile ZScript. Then import wallflower.z, compile it, and put it in a script slot.

Then make a ffc on the screen you want it on, and pass in the parameters with D0-4.

[Pheonix]

I see the problem. Thanks.

[Hot Water Music]

Like those bubbles in Link's Awakening that move along the wall.
You should make it so if you hit it with a boomarange, it spawns a fairy.

[C-Dawg]

And you can, Hot Water Music. Thanks for volunteering.

1. Set up a custom "fire" enemy with no attacks, invisible, vulnerable only to the boomerang.
2. Add the enemy_ghosting script to this script, or make a second FFC that runs that script.
3. Add a bit to the script that spawns a fairy and moves the FFC to -16,-16 when the invisible fire enemy loses hit points.
4. Profit.