Difference between revisions of "Shields"

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(I don't have time to fix all this up, but TSO uses invo now, not skill)
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{{version012}}
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{{version019}}
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{{flavour|“Let who will boast their courage in the field,<br>
 +
I find but little safety from my shield.<br>
 +
Nature's, not honour's, law we must obey:<br>
 +
This made me cast my useless shield away,<br>
 +
And by a prudent flight and cunning save<br>
 +
A life, which valour could not, from the grave.<br>
 +
A better buckler I can soon regain;<br>
 +
But who can get another life again?”<br>
 +
-Archilochos. 7th cent. B.C. trans. William H. Goodwin, 1878.}}
 +
 
 
[[Shields]] are a kind of armour worn in one hand, preventing the use of two handed weapons, which use the [[Shields skill]]. Unlike other armour, shields increase a character's [[SH]] defense, giving you a chance at blocking physical (and some magical) attacks entirely. Certain spells can also grant you an SH score.
 
[[Shields]] are a kind of armour worn in one hand, preventing the use of two handed weapons, which use the [[Shields skill]]. Unlike other armour, shields increase a character's [[SH]] defense, giving you a chance at blocking physical (and some magical) attacks entirely. Certain spells can also grant you an SH score.
  
 
==Shield Penalties==
 
==Shield Penalties==
Wearing a shield also gives penalties to attack speed, attack damage, and spellcasting, along with EV penalties of -1 ([[buckler]]), -3 ([[shield]]), or -5 ([[large shield]]). While the penalty for wearing a small [[buckler]] is almost negligible, a [[large shield]] can seriously slow your attacks and make spellcasting unreliable. Sufficient Shields skill will reduce or even negate these penalties, but the amount needed varies by race:
+
Wearing a shield also gives penalties to attack speed, attack damage, and spellcasting, along with EV penalties of -0.8 ([[buckler]]), -3 ([[shield]]), or -5 ([[large shield]]). While the penalty for wearing a small [[buckler]] is almost negligible, a [[large shield]] can seriously slow your attacks and make spellcasting unreliable. Sufficient Shields skill will reduce or even negate these penalties. The amount needed varies by race, but can be found in the description of the shield in-game:
  
 
{| class="prettytable" cellpadding="10" border="9"
 
{| class="prettytable" cellpadding="10" border="9"
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! Size !! Races !! Buckler !! Shield !! Large shield
 
! Size !! Races !! Buckler !! Shield !! Large shield
 
|-
 
|-
|Little || [[Spriggan]] || 9 || - || -
+
|Little || [[Spriggan]] || 7.2 || - || -
 
|-
 
|-
|Small || [[Kobold]], [[Halfling]] || 7 || 21 || -
+
|Small || [[Kobold]], [[Halfling]] || 5.6 || 21 || -
 
|-
 
|-
|Normal || most races || 5 || 15 || 25
+
|Normal || most races || 4 || 15 || 25
 
|-
 
|-
|Large<br>(normal torso) || [[Centaur]], [[Naga]] || 3 || 9 || 15
+
|Large (normal torso)<br> & Formicids || [[Centaur]], [[Naga]], [[Formicid]] || 2.4 || 9 || 15
 
|-
 
|-
 
|Large || [[Ogre]], [[Troll]] || - || 9 || 15
 
|Large || [[Ogre]], [[Troll]] || - || 9 || 15
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! Shield type !! Shield EV penalty
 
! Shield type !! Shield EV penalty
 
|-
 
|-
|Buckler || -1
+
|Buckler || -0.8
 
|-
 
|-
 
|Shield || -3
 
|Shield || -3
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|Normal || most races || 0
 
|Normal || most races || 0
 
|-
 
|-
|Large<br>(normal torso) || [[Centaur]], [[Naga]] || -2
+
|Large<br>(normal torso) & Formicids || [[Centaur]], [[Naga]], [[Formicid]] || -2
 
|-
 
|-
 
|Large || [[Ogre]], [[Troll]] || -2
 
|Large || [[Ogre]], [[Troll]] || -2
 
|}
 
|}
  
If you are wearing a shield, wielding a one-handed weapon, and your Shield penalty is greater than zero, the game throws two dices with (Shield penalty) sides. The smaller one is added to your delay.
+
When attacking with any kind of weapon (including unarmed), if you are wearing a shield and your Shield penalty is greater than zero, the game throws two dice with (Shield penalty) sides. The smaller value rolled is added to your attack delay.
 
 
The penalty for [[unarmed combat]] is like the penalty for one-handed weapons, but your delay is increased by one [[aut]], 50% of the time, regardless of your Shield penalty.
 
 
 
If you are wearing a 0 EVP armour, you need less shield skill to eliminate just the casting penalties:
 
{| class="prettytable" cellpadding="10" border="9"
 
|- align="center"
 
! Size !! Races !! Buckler !! Shield !! Large shield
 
|-
 
|Little || [[Spriggan]] || 1.53 || - || -
 
|-
 
|Small || [[Kobold]], [[Halfling]] || 1.19 || 15.19 || -
 
|-
 
|Normal || most races || 0.85 || 10.85 || 20.85
 
|-
 
|Large<br>(normal torso) || [[Centaur]], [[Naga]] || 0.51 || 6.51 || 12.51
 
|-
 
|Large || [[Ogre]], [[Troll]] || - || 6.51 || 12.51
 
|}
 
  
 
==Blocking==
 
==Blocking==
 
===Effect===
 
===Effect===
It's possible to block a melee attack if you wear a shield of some kind or are under the effect of a magical shield (the [[Helm]] card's Magic Shield, the [[Ice Magic]] spell [[Condensation Shield]], or [[The Shining One]]'s Divine Shield). Ranged attacks can be blocked only with physical shields, like bucklers, shields, large shields or the [[Good_mutations#Large_Bone_Plates|Large Bones Plates]] mutation. [[The Shining One]]'s Divine Shield will help you to block missiles only if you already have a physical of some kind. Your ability to block missiles doesn't get any benefit from spells like [[Repel Missiles]] or [[Deflect Missiles]]. If the attacker's pierce value is less than the defender's blocking value, the attack does no damage. Shield blocking is done before rolling your [[evasion]] or your [[AC]], but if you have already blocked some attacks in that turn, your blocking ability will be decreased greatly.  
+
It's possible to block a melee attack or a ranged projectile attack if you wear a shield of some kind or are under the effect of a magical shield (the [[Helm card]]'s Magic Shield, [[Qazlal]]'s Storm Shield, or [[the Shining One]]'s Divine Shield) or have the [[Good_mutations#Large_Bone_Plates|Large Bones Plates]] mutation. Your ability to block missiles doesn't benefit from spells like [[Repel Missiles]] or [[Deflect Missiles]]. If the attacker's pierce value is less than the defender's blocking value, the attack does no damage. Shield blocking is done before rolling your [[evasion]] or your [[AC]], but if you have already blocked some attacks in that turn, your blocking ability will be decreased greatly.  
  
 
All melee attacks can be blocked (except a successful stabbing), but many ranged attacks are unblockable:
 
All melee attacks can be blocked (except a successful stabbing), but many ranged attacks are unblockable:
  
*Bolt spells: [[Bolt of Fire]], [[Bolt of Cold]], [[Lightning Bolt]], [[Bolt of Draining]], [[Venom Bolt]], [[Bolt of Magma]], [[Bolt of Inaccuracy]], [[Shock]]
+
*Bolt spells: [[Bolt of Fire]], [[Bolt of Cold]], [[Lightning Bolt]], [[Bolt of Draining]], [[Venom Bolt]], [[Bolt of Magma]], [[Bolt of Inaccuracy]], [[Shock]], and the 4th ray of [[Searing Ray]]
*Explosions: [[Fireball]], [[Hellfire]], [[Fire Storm]], [[Ice Storm]], [[Conjure Ball Lightning]], [[Lee's Rapid Deconstruction]], [[exploding (brand)|exploding]]-branded weapons
+
*Explosions: [[Fireball]], [[Hellfire]], [[Fire Storm]], [[Conjure Ball Lightning]], [[Lee's Rapid Deconstruction]], [[exploding (brand)|exploding]]-branded weapons
*Other electricity-based beams: [[Chain Lightning]]
+
*Other electricity-based beams: [[Static Discharge]], [[Chain Lightning]]
*Enchantments: [[Agony]], [[Pain]], etc
+
*Enchantments: [[Agony]], [[Pain]], [[Confuse]], [[Mesmerise]], etc
 
*Beams with perfect accuracy: [[Magic Dart]], [[Sticky Flame]] (only the player's version)
 
*Beams with perfect accuracy: [[Magic Dart]], [[Sticky Flame]] (only the player's version)
 
*Other ranged attacks that are not beams: [[Shatter]], [[Tornado]], [[Airstrike]], [[Smite]], [[Ozocubu's Refrigeration]], [[Freeze]], etc
 
*Other ranged attacks that are not beams: [[Shatter]], [[Tornado]], [[Airstrike]], [[Smite]], [[Ozocubu's Refrigeration]], [[Freeze]], etc
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The defender's blocking value depends on the nature of the shield:
 
The defender's blocking value depends on the nature of the shield:
  
*Physical shields:
+
Physical shields:
  SH = Block × (1 + Shield skill/20 + Racial bonus/30)
+
  SH = Block × (1 + Shield skill/40)
 
  + Enchantment bonus + Stat bonus  
 
  + Enchantment bonus + Stat bonus  
+ Divine shield bonus (this bonus also works without a shield)
+
  + min(0.38×Shield skill, .57 + 0.19×Shield skill)
  + min(0.76×Shield skill, 1.14 + 0.38×Shield skill) (added only if the sum of the previous terms is > 0)
 
+ Mutation bonus
 
+ 0.5 (final value is rounded down)
 
  
*[[Helm card]]:
+
or [[Helm card]] (this does not stack with a physical shield):
  SH = 9 + 0.75×[[Evocations]]
+
  SH = 4.5 + 0.375×[[Invocations]]
+ Divine shield bonus + Mutation bonus
 
+ 0.5 (final value is rounded down)
 
  
*[[Condensation shield]]:
+
and then on top of either of those:
  SH = 8 + 0.60×[[Ice magic]]
+
  + Divine shield bonus
  + Divine shield bonus + Mutation bonus
+
  + Qazlal shield bonus
  + 0.5 (final value is rounded down)
+
+ Mutation bonus
 +
  + Cigotuvi's Embrace bonus
 +
+ Amulet of reflection bonus
 +
+ Any SH bonus from artifacts
 +
 
  
 
For a physical shield (Buckler, Shield and Large Shield), '''Block''' is the shield's blocking value, equal to the base shield bonus (3 for Buckler, 8 for Shield, 13 for Large Shield), modified by a size factor:
 
For a physical shield (Buckler, Shield and Large Shield), '''Block''' is the shield's blocking value, equal to the base shield bonus (3 for Buckler, 8 for Shield, 13 for Large Shield), modified by a size factor:
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|Normal || most races || 0 || 0 || 0
 
|Normal || most races || 0 || 0 || 0
 
|-
 
|-
|Large<br>(normal torso) || [[Centaur]], [[Naga]] || 0 || 0 || 0
+
|Large<br>(normal torso) & Formicids || [[Centaur]], [[Naga]], Formicid || 0 || 0 || 0
 
|-
 
|-
 
|Large || [[Ogre]], [[Troll]] || - || -0.5 || 0
 
|Large || [[Ogre]], [[Troll]] || - || -0.5 || 0
 
|}
 
|}
  
*'''Racial bonus''' is +4 (+13%) for dwarven shields (+8 (+26%) for dwarves), by +2 (+7%) for elves wearing elven shields and by +4 (+13%) for orcs wearing orcish shields (up to +9 (+30%) for high-piety followers of Beogh).
+
*'''Stat bonus''' is 38×DEX for bucklers, 19×STR + 19×DEX for shields, or 26×STR + 12×DEX for large shields. Then this value is multiplied by (block + 13)/26, and by 100.
  
*'''Stat bonus''' is 0.38×DEX for bucklers (you get +1SH for every 2.6 points of DEX) , 0.19×STR + 0.19×DEX for shields (you get +1SH for every 5.3 points of DEX or STR), and 0.26×STR + 0.12×DEX for large shields (you get +1SH for every 3.9 points of STR or 8.3 points of DEX).
+
*The Shining One's '''Divine shield bonus''' is based on Invocations skill.
  
*The Shinining One's '''Divine shield bonus''' is 4.5 + 0.3×Shield skill. Your stat bonus will be increased to (9 + 0.6×Shield skill) if it was smaller.
+
*'''Mutation bonus''' is +2/4/6 SH depending on your level of the [[Good_mutations#Large_Bone_Plates|Large Bones Plates]] mutation.
  
*'''Mutation bonus''' is +2 SH per every level of the [[Good_mutations#Large_Bone_Plates|Large Bones Plates]] mutation.
+
The resulting value is rounded to the nearest integer and displayed as the player's SH value.
 
 
The resulting value is displayed as the player's SH value.
 
  
 
For reference, a 15-Dex, 15-Str character wearing a buckler has an average blocking value of:
 
For reference, a 15-Dex, 15-Str character wearing a buckler has an average blocking value of:
*7 with a Shield Skill of 0
+
*3 with a Shield Skill of 0
*13 with a Shield Skill of 8
+
*6 with a Shield Skill of 8
*16 with a Shield skill of 15
+
*8 with a Shield skill of 15
*23 with a Shield skill of 27
+
*11 with a Shield skill of 27
  
 
With a large shield, it becomes:
 
With a large shield, it becomes:
*22 with a Shield Skill of 0
+
*11 with a Shield Skill of 0
*31 with a Shield Skill of 8
+
*15 with a Shield Skill of 8
*38 with a Shield skill of 15
+
*19 with a Shield skill of 15
*51 with a Shield skill of 27
+
*25 with a Shield skill of 27
  
 
The attacker's pierce value is equal to:
 
The attacker's pierce value is equal to:
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If this value is greater or equal than the attacker's pierce value, the attack is blocked.
 
If this value is greater or equal than the attacker's pierce value, the attack is blocked.
  
[[Category:Item]]
+
==History==
 +
*Prior to [[0.17]], [[unarmed]] attacks had a speed penalty when attacking with a shield equipped.
 +
*Prior to [[0.16]], the amount of skill required to negate penalties for wearing a shield were more complex.
 +
 
 +
[[Category:Items]]
 
[[Category:Shields]]
 
[[Category:Shields]]
 +
[[Category:Crystal Ball Articles]]

Revision as of 01:23, 20 January 2019

Version 0.19: This article may not be up to date for the latest stable release of Crawl.
“Let who will boast their courage in the field,

I find but little safety from my shield.
Nature's, not honour's, law we must obey:
This made me cast my useless shield away,
And by a prudent flight and cunning save
A life, which valour could not, from the grave.
A better buckler I can soon regain;
But who can get another life again?”
-Archilochos. 7th cent. B.C. trans. William H. Goodwin, 1878.

Shields are a kind of armour worn in one hand, preventing the use of two handed weapons, which use the Shields skill. Unlike other armour, shields increase a character's SH defense, giving you a chance at blocking physical (and some magical) attacks entirely. Certain spells can also grant you an SH score.

Shield Penalties

Wearing a shield also gives penalties to attack speed, attack damage, and spellcasting, along with EV penalties of -0.8 (buckler), -3 (shield), or -5 (large shield). While the penalty for wearing a small buckler is almost negligible, a large shield can seriously slow your attacks and make spellcasting unreliable. Sufficient Shields skill will reduce or even negate these penalties. The amount needed varies by race, but can be found in the description of the shield in-game:

Size Races Buckler Shield Large shield
Little Spriggan 7.2 - -
Small Kobold, Halfling 5.6 21 -
Normal most races 4 15 25
Large (normal torso)
& Formicids
Centaur, Naga, Formicid 2.4 9 15
Large Ogre, Troll - 9 15

Your Shield penalty is (Shield EV penalty) - (Shields skill)/(5 + (Size factor)). Shield EV penalty and Size factor can be looked up in these tables:

Shield type Shield EV penalty
Buckler -0.8
Shield -3
Large shield -5
Size Races Size factor
Little Spriggan +4
Small Kobold, Halfling +2
Normal most races 0
Large
(normal torso) & Formicids
Centaur, Naga, Formicid -2
Large Ogre, Troll -2

When attacking with any kind of weapon (including unarmed), if you are wearing a shield and your Shield penalty is greater than zero, the game throws two dice with (Shield penalty) sides. The smaller value rolled is added to your attack delay.

Blocking

Effect

It's possible to block a melee attack or a ranged projectile attack if you wear a shield of some kind or are under the effect of a magical shield (the Helm card's Magic Shield, Qazlal's Storm Shield, or the Shining One's Divine Shield) or have the Large Bones Plates mutation. Your ability to block missiles doesn't benefit from spells like Repel Missiles or Deflect Missiles. If the attacker's pierce value is less than the defender's blocking value, the attack does no damage. Shield blocking is done before rolling your evasion or your AC, but if you have already blocked some attacks in that turn, your blocking ability will be decreased greatly.

All melee attacks can be blocked (except a successful stabbing), but many ranged attacks are unblockable:

Some examples of ranged attacks that can be blocked: Iron shot, Poison Arrow, Orb of Destruction, Lehudib's Crystal Spear, Iskenderun's Mystic Blast (the explosion is special), Throw Icicle, Stone Arrow, Throw Flame, Throw Frost, Flame Tongue, Sting, Sandblast

Calculation

The defender's blocking value depends on the nature of the shield:

Physical shields:

SH = Block × (1 + Shield skill/40)
+ Enchantment bonus + Stat bonus 
+ min(0.38×Shield skill, .57 + 0.19×Shield skill)

or Helm card (this does not stack with a physical shield):

SH = 4.5 + 0.375×Invocations

and then on top of either of those:

+ Divine shield bonus
+ Qazlal shield bonus
+ Mutation bonus
+ Cigotuvi's Embrace bonus
+ Amulet of reflection bonus
+ Any SH bonus from artifacts
 

For a physical shield (Buckler, Shield and Large Shield), Block is the shield's blocking value, equal to the base shield bonus (3 for Buckler, 8 for Shield, 13 for Large Shield), modified by a size factor:

Size Races Buckler Shield Large shield
Little Spriggan +2 - -
Small Kobold, Halfling +1 +0.5 -
Normal most races 0 0 0
Large
(normal torso) & Formicids
Centaur, Naga, Formicid 0 0 0
Large Ogre, Troll - -0.5 0
  • Stat bonus is 38×DEX for bucklers, 19×STR + 19×DEX for shields, or 26×STR + 12×DEX for large shields. Then this value is multiplied by (block + 13)/26, and by 100.
  • The Shining One's Divine shield bonus is based on Invocations skill.

The resulting value is rounded to the nearest integer and displayed as the player's SH value.

For reference, a 15-Dex, 15-Str character wearing a buckler has an average blocking value of:

  • 3 with a Shield Skill of 0
  • 6 with a Shield Skill of 8
  • 8 with a Shield skill of 15
  • 11 with a Shield skill of 27

With a large shield, it becomes:

  • 11 with a Shield Skill of 0
  • 15 with a Shield Skill of 8
  • 19 with a Shield skill of 15
  • 25 with a Shield skill of 27

The attacker's pierce value is equal to:

1d(15 + to hit/2 + 5×past_blocks^2) - 1 (melee attacks)
1d(1.3×to hit    + 5×past_blocks^2) - 1 (ranged attacks)   

"To hit" is the monster's To hit value (based primarily on the monster's HD, type, and weapon accuracy) and "past_blocks" is the number of attacks already successfully blocked in the current turn.

The defender's blocking value is equal to:

 2d(2×SH)/6 - 1.3 (Divided by 3 against melee attacks from invisible opponents)

If this value is greater or equal than the attacker's pierce value, the attack is blocked.

History

  • Prior to 0.17, unarmed attacks had a speed penalty when attacking with a shield equipped.
  • Prior to 0.16, the amount of skill required to negate penalties for wearing a shield were more complex.