The "How do I..." Thread

[Blue Shadow]

This code doesn't really work properly at times, it gives me odd results and it's quite possibly because I failed to convert the angle right. How can I do it ?

Edit:

Spoiler: Dismiss this and instead see FDARI's post below

I think what you can do is provide the angle as byte angle and then convert it to fixed-point angle to be used by SetActorAngle:

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TNT1 A 0 ACS_ExecuteAlways(998, 0, random(32, 96))

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Script 998 (int angle)
{
  angle = angle << 8;

  SetActorAngle(0, GetActorAngle(0) + angle);
}


Unless you're using UDMF, in which case you can set the line's tag and flags directly.

Yep, you can do that in UDMF. As a matter of fact and as far as UDMF is concerned that special doesn't even exist in that format.

However, I believe he's using hexen-format, hence why I suggested the use of the special...

I am working under GZDoom conditions with Hexen...

[FDARI]

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TNT1 A 0 ACS_ExecuteAlways(998, 0, random(-36,36), angle)

Script 998 (int angle, int firstangle)
{
   SetActorAngle(0, angle + firstangle);
}


This code doesn't really work properly at times, it gives me odd results and it's quite possibly because I failed to convert the angle right. How can I do it ? (First part is in decorate)

For reference, check out Definitions. ACS functions either take BYTE angles (0-255), or fixed point angles (0.0-0.1).

(Byte angles: 360 degrees divides a circle in 360 parts, this divides a circle in 255 parts, but is otherwise similar.)

Decorate uses the same angles as the zdoom engine, but for decorate expressions and functions it converts to a number of degrees (0-360). In your code, the decorate expression "angle" returns a number within 360 degrees, rounded off to an integer for ACS. You need to convert this to a fixed point angle.

Spoiler: Extra descriptions if the wiki doesn't make it clear

x<<16: Convert to fixed point number. However, this will be in the range 0.0 - 360.0.
(x<<16)/360: This should put you in the range 0.0 - 1.0

360<<16 = 360.0
360.0 / 360 = 1.0

180<<16 = 180.0
180 / 360 = 0.5

Note: I divide fixed point integer by regular integer; that works ok.
Fixed/int: 360.0 / 360 = 1.0
Fixed/fixed: 360.0 / 360.0 = 1
They're both really ints, "the fixed point representation of a number = that number * 65536. ".

Spoiler: modified code

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TNT1 A 0 ACS_ExecuteAlways(998, 0, random(-36,36), angle) // 0 - 360

Script 998 (int angle, int firstangle)
{
    // number of degrees: angle + firstangle
    // number of degrees in fixed point: (angle + firstangle)<<16
    // fixed point angle: ((angle + firstangle)<<16)/360
   SetActorAngle(0, ((angle + firstangle)<<16)/360);
}

Spoiler: More modified code

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TNT1 A 0 ACS_ExecuteAlways(998, 0, ((frandom(-36,36) + angle) * 65536)/360)
// You'll be adding the angles together; can do that in decorate
// Passing the angle to ACS loses precision (only whole degrees can be sent); precision loss is reduced if we make the calculations before roundoff
// You probably don't need all that precision, but it might be nice to know.
// I used frandom, working with floats. That means the result can be a fraction of a degree. You may want to stick with regular random - I'm just putting it out there.
Script 998 (int fp_angle)
{
    SetActorAngle(0, fp_angle);
}

[Reactor]

Thanks for the reply, I've modified the properties of the line right away. It's looking good!

[insightguy]

how do you build poly objects in doom builder 2?

and how do you make "hitscan" projectiles without them firing the wrong way?

[terranova]

and how do you make "hitscan" projectiles without them firing the wrong way?

Huh? They fire in your back or something?

[Blue Shadow]

how do you build poly objects in doom builder 2?

PolyObjects

[insightguy]

and how do you make "hitscan" projectiles without them firing the wrong way?

Huh? They fire in your back or something?

I've seen people complaining about them firing the wrong way. Can it just be like a normal projectile or do special things need to be added to every "bullet's" decorate

[ChronoSeth]

That still doesn't explain what you mean...

What is the "wrong way"?

[Vaecrius]

Maybe like a projectile that shoots hitscans? (In which case you have to make sure that the projectile is no longer targeting its own shooter before it itself starts shooting)

[cypherphage]

Hitscans and bullets aren't the same thing. Posting the code you think is in error and describing the unintended behavior would help.

[insightguy]

hold on. I wasn't thinking strait.

2 problems:

1.How do you make them less accurate/spread more? I end up getting really accurate rapid fire!

2.enemies seem to be firing the bullets in the wrong direction. why?

[cocka]

http://zdoom.org/wiki/A_FireBullets

This might be helpful for this problem. Have you used that?

[insightguy]

I'm looking for projectile bullets, not hitscan. nice try anyway

[cocka]

Oh, I see.

[Blue Shadow]

I guess you can use the angle and pitch parameters in A_FireCustomMissile and A_CustomMissile with frandom to randomize the spread. Angle and pitch are in degrees if I'm not mistaken.

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A_FireCustomMissile("Bullet", frandom(-5, 5), 1, 0, 0, 0, frandom(-5, 5))