Genre: Card Game

Expert blueprint for digital card games with data-driven design and juicy UI.

NEVER Do

NEVER hardcode card effects in card scripts

— Use Command pattern or effect_script Resource. Enables designers to create cards without code.

NEVER use global_position for hand layout

— Hand cards should use local positions relative to hand container. global_position breaks with camera movement.

NEVER forget to shuffle discard into draw pile

— When draw_pile is empty, reshuffle discard_pile. Otherwise game soft-locks.

NEVER skip z_index management

— Dragged cards must have highest z_index. Use

move_to_front()

or set

z_index = 999

.

NEVER use instant card movements

— Cards without tween animations feel terrible. Even 0.2s tweens massively improve feel.

Available Scripts

MANDATORY

Read the appropriate script before implementing the corresponding pattern.

card_effect_resolution.gd

FILO stack for card effect resolution. Enables reaction/counter cards (last-in resolves first), visual pass for animations, and polymorphic effect dispatch.

Core Loop

Draw

Player draws cards from a deck into their hand.

Evaluate

Player assesses board state, mana/energy, and card options.

Play

Player plays cards to trigger effects (damage, buff, summon).

Resolve

Effects occur immediately or go onto a stack.

Discard/End

Unused cards are discarded (roguelike) or kept (TCG), turn ends. Skill Chain Phase Skills Purpose 1. Data resources , custom-resources Defining Card properties (Cost, Type, Effect) 2. UI control-nodes , layout-containers Hand layout, card positioning, tooltips 3. Input drag-and-drop , state-machines Dragging cards to targets, hovering 4. Logic command-pattern , signals Executing card effects, turn phases 5. Polish godot-tweening , shaders Draw animations, holographic foils Architecture Overview 1. Card Data (Resource-based) Godot Resources are perfect for card data.

card_data.gd

extends Resource class_name CardData enum Type { ATTACK , SKILL , POWER } enum Target { ENEMY , SELF , ALL_ENEMIES } @ export var id : String @ export var name : String @export_multiline var description : String @ export var cost : int @ export var type : Type @ export var target_type : Target @ export var icon : Texture2D @ export var effect_script : Script

Custom logic per card

1. Deck Manager Handles the piles: Draw Pile, Hand, Discard Pile, Exhaust Pile.

deck_manager.gd

var draw_pile : Array [ CardData ] = [ ] var hand : Array [ CardData ] = [ ] var discard_pile : Array [ CardData ] = [ ] func draw_cards ( amount : int ) -> void : for i in amount : if draw_pile . is_empty ( ) : reshuffle_discard ( ) if draw_pile . is_empty ( ) : break

No cards left

var card = draw_pile . pop_back ( ) hand . append ( card ) card_drawn . emit ( card ) func reshuffle_discard ( ) -> void : draw_pile . append_array ( discard_pile ) discard_pile . clear ( ) draw_pile . shuffle ( ) 3. Card Visual (UI) The interactive node representing a card in hand.

card_ui.gd

extends Control var card_data : CardData var start_pos : Vector2 var is_dragging : bool = false func _gui_input ( event : InputEvent ) -> void : if event is InputEventMouseButton and event . button_index == MOUSE_BUTTON_LEFT : if event . pressed : start_drag ( ) else : end_drag ( ) func _process ( delta : float ) -> void : if is_dragging : global_position = get_global_mouse_position ( ) - size / 2 else :

Hover effect or return to hand position

pass Key Mechanics Implementation Effect Resolution (Command Pattern) Decouple the "playing" of a card from its "effect". func play_card ( card : CardData , target : Node ) -> void : if current_energy < card . cost : show_error ( "Not enough energy" ) return current_energy -= card . cost

Execute effect

var

effect

=

card

.

effect_script

.

new

(

)

effect

.

execute

(

target

)

move_to_discard

(

card

)

Hand Layout (Arching)

Cards in hand usually form an arc. Use a math formula (Bezier or Circle) to position them based on

index

and

total_cards

.

func

update_hand_visuals

(

)

->

void

:

var

center_x

=

screen_width

/

2

var

radius

=

1000.0

var

angle_step

=

5.0

for

i

in

hand_visuals

.

size

(

)

:

var

card

=

hand_visuals

[

i

]

var

angle

=

deg_to_rad

(

(

i

-

hand_visuals

.

size

(

)

/

2.0

)

*

angle_step

)

var

target_pos

=

Vector2

(

center_x

+

sin

(

angle

)

*

radius

,

screen_height

+

cos

(

angle

)

*

radius

)

card

.

target_rotation

=

angle

card

.

target_position

=

target_pos

Common Pitfalls

Complexity Overload

Too many keywords.

Fix

Stick to 3-5 core keywords (e.g., Taunt, Poison, Shield) and expand slowly.

Unreadable Text

Tiny fonts on cards.

Fix

Use icons for common stats (Damage, Block) and keep text short.

Animation Lock

Waiting for slow animations to finish before playing the next card.

Fix

Allow queueing actions or keep animations snappy (< 0.3s).

Godot-Specific Tips

MouseFilter

Getting drag/drop to work with overlapping UI requires careful setup of

mouse_filter

(Pass vs Stop).

Z-Index

Use

z_index

or

CanvasLayer

to ensure the dragged card is always on top of everything else.

Tweens

Essential! Tween position, rotation, and scale for that "juicy" Hearthstone/Slay the Spire feel. Reference Master Skill: godot-master