"How do I ZScript?"

[Graf Zahl]

Well, in particular, finding the vertices is what I'm after. I think I can handle the rest, and they're all triangles. What function can I use to find them?

The only way to find the vertices is to check all linedefs belonging to a sector and look at their vertices. What are you trying to do here?

[Major Cooke]

I'm trying to roll sprites along a slope like this. (This is from Darwinia)

[Graf Zahl]

Ugh.

No idea how to express that in yaw/pitch/roll...

[Rachael]

This may be a bit hacky but it's the easiest way I know of to do this: (and please don't ask me for the code, you know ZScript better than I do so you're on your own)

Each actor has two "check" actors that they spawn as children. One that's one pixel ahead, and one that's one pixel to the side. These checks are relative to the main actor's yaw, so if the actor rotates it rotates along with it. These check actors have the +FLOORHUGGER property in order to be in an absolute position on the floor.

Since these checks are only one pixel offset, it's pretty easy to just get the arctangents:

For the ahead actor, do arctan(me.zheight-check1.zheight) - that's your forward facing angle.
For the side actor, do arctan(me.zheight-check2.zheight) - that's your roll.

Multiply the angles by *-1 if they do not look right.

[Graf Zahl]

The proper way should of course be to read the current floor's normal and transform it into a set of angles. It's just that I do not know the math for that.

[Rachael]

I got as far as College Algebra in math. Beyond that, I cannot help you.

[Major Cooke]

Ugh.

No idea how to express that in yaw/pitch/roll...

And I just remembered I own the darwinia source code. The rendering is done via a Matrix34 (it uses OpenGL as well), looking more into the details on that...

In the mean time, doesn't bouncing have some manner of recalculating which direction to go? Maybe I could use that...

I can handle the yaw/pitch/roll myself, I just need to find out how steep it can dip, and at what angle. That's why I'm trying to get all three vertices.

[Graf Zahl]

Bouncing just uses the plane normal with a few multiplications. The problem you are facing is different: Finding what you need to set the angles to to get the desired orientation,

[kodi]

Correct me if I'm wrong, but wouldn't it be better to measure the height at each corner of the actor and calculate the normal between those points, allowing you to smoothly angle the sprite over sharp edges rather than snapping instantly while also allowing you to angle the sprite on stairs if you so wish?

[Major Cooke]

I feel like this is where Trace could be of use in a way...

Anyway I did some digging into the Darwinia source code. I wouldn't be surprised if it's not of any help.

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Code: Select all

T SurfaceMap2D<T>::GetValue(float _x, float _y) const
{
	// These variables (all m_ vars) are used when converting from real co-ords into
	// array indices
	_x -= m_x0;
	_y -= m_y0;

	float fractionalX = _x * m_invCellSizeX;
	float fractionalY = _y * m_invCellSizeY;

	unsigned short x1 = fractionalX;
	unsigned short y1 = fractionalY;
	unsigned short x2 = x1 + 1;
	unsigned short y2 = y1 + 1;

	fractionalX = fractionalX - floorf(fractionalX);
	fractionalY = fractionalY - floorf(fractionalY);

	if (x1 >= m_numColumns) x1 = 0;
	if (x2 >= m_numColumns) x2 = 0;
	if (y1 >= m_numRows) y1 = 0;
	if (y2 >= m_numRows) y2 = 0;

	T value11 = GetData(x1, y1);
	T value12 = GetData(x1, y2);
	T value21 = GetData(x2, y1);
	T value22 = GetData(x2, y2);

	float weight11 = (1.0f - fractionalX) * (1.0f - fractionalY);
	float weight12 = (1.0f - fractionalX) * (fractionalY);
	float weight21 = (fractionalX) * (1.0f - fractionalY);
	float weight22 = (fractionalX) * (fractionalY);

	T returnVal = value11 * weight11 +
				  value12 * weight12 +
				  value21 * weight21 +
				  value22 * weight22;

	return returnVal;
}

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    Vector3 moved = newPos - oldPos;
    //Mag is exactly GZDoom's Length() function
    if( moved.Mag() > speed * 0.1f ) moved.SetLength( speed * 0.1f );
    newPos = m_pos + moved;

    m_pos = newPos;
    m_vel = ( m_pos - oldPos ) / 0.1f;
    m_front = ( newPos - oldPos ).Normalise();

Code: Select all

 //Some declarators I found...
Vector3 m_front; //(Just a set of coordinates in front of the entities, direction-wise, for changing their pitch/yaw/roll up to on the landscape.
Vector3 const g_upVector(0.0f, 1.0f, 0.0f);
Vector3 entityUp = g_upVector;
Vector3 entityRight(m_front ^ entityUp);
Vector3 predictedPos = m_pos + m_vel * _predictionTime;;

The actual rendering.

Code: Select all

    float size = 3.0f;
    size *= (1.0f + 0.03f * (( m_id.GetIndex() * m_id.GetUniqueId() ) % 10));
    entityRight *= size;
    entityUp *= size * 2.0f;

        glBegin(GL_QUADS);
            glTexCoord2i(0, 1);     glVertex3fv( (predictedPos - entityRight + entityUp).GetData() );
            glTexCoord2i(1, 1);     glVertex3fv( (predictedPos + entityRight + entityUp).GetData() );
            glTexCoord2i(1, 0);     glVertex3fv( (predictedPos + entityRight).GetData() );
            glTexCoord2i(0, 0);     glVertex3fv( (predictedPos - entityRight).GetData() );
        glEnd();

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	float *GetData()
	{
		return &x;
	}

	Vector3 const &Normalise()
	{
		float lenSqrd = x*x + y*y + z*z;
		if (lenSqrd > 0.0f)
		{
			float invLen = 1.0f / sqrtf(lenSqrd);
			x *= invLen;
			y *= invLen;
			z *= invLen;
		}
		else
		{
			x = y = 0.0f;
			z = 1.0f;
		}

		return *this;
	}

	Vector3 const &SetLength(float _len)
	{
		float mag = Mag();
		if (NearlyEquals(mag, 0.0f))
		{
			x = _len;
			return *this;
		}

		float scaler = _len / Mag();
		*this *= scaler;
		return *this;
	}

@kodi unfortunately I've tried doing a bunch of hacks to find lower and upper places where things consider floorz at but unfortunately, I've had no luck.

[krokots]

How can I change A_SkullAttack so that Lost Souls will not hurt themselves when charging?

[Graf Zahl]

You can't. A_SkullAttack only adds some velocity to the Lost Soul.
The only option you have is to override the virtual Slam method in ZScript in a child class.

[krokots]

You can't. A_SkullAttack only adds some velocity to the Lost Soul.
The only option you have is to override the virtual Slam method in ZScript in a child class.

Code: Select all

override bool Slam(Actor victim)
{
	if (victim.GetSpecies() == self.GetSpecies()) 
		return false;
	Super.Slam(victim);
	return false;
}

This works. Thanks!

[Agentbromsnor]

I know I've asked this before, but I couldn't really figure out how to go about this. I'm trying to get a smooth player-animation for my 2D platform-game, because ever since I converted my DECORATE code to ZScript the player's animation has been looking very choppy. Major Cooke replied to this question before, but I couldn't figure out where to go from there. Can anyone explain to me what I need to do fix this?

[Major Cooke]

Try pming zombiekiller about it directly. I don't have the file anymore myself.