Initial commit

src/assets/gfx/ui/spellbook_cover_small.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://bpk136b7ld4rm"
+path="res://.godot/imported/spellbook_cover_small.png-c8007902877b53ad13e98c79605b99d6.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/gfx/ui/spellbook_cover_small.png"
+dest_files=["res://.godot/imported/spellbook_cover_small.png-c8007902877b53ad13e98c79605b99d6.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

src/assets/gfx/ui/spine_inner_binding.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://ckrthw12d1gwb"
+path="res://.godot/imported/spine_inner_binding.png-fa5d560b7cfc1892b8181ab9e269f289.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/gfx/ui/spine_inner_binding.png"
+dest_files=["res://.godot/imported/spine_inner_binding.png-fa5d560b7cfc1892b8181ab9e269f289.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
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+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

src/assets/gfx/ui/spine_inner_binding_small.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://wcpely4edb4a"
+path="res://.godot/imported/spine_inner_binding_small.png-1afe3288b0162c03127f1d9584faddba.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
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+dest_files=["res://.godot/imported/spine_inner_binding_small.png-1afe3288b0162c03127f1d9584faddba.ctex"]
+
+[params]
+
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+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

src/assets/gfx/ui/spine_leather_small.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://bgq3fup6clg8y"
+path="res://.godot/imported/spine_leather_small.png-188cfce5b6aa1942b496990b84d5db37.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/gfx/ui/spine_leather_small.png"
+dest_files=["res://.godot/imported/spine_leather_small.png-188cfce5b6aa1942b496990b84d5db37.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

src/default_bus_layout.tres

@@ -5,11 +5,6 @@ resource_name = "Reverb"
 room_size = 0.51
 wet = 0.28
 
-[sub_resource type="AudioEffectLowPassFilter" id="AudioEffectLowPassFilter_j3pel"]
-resource_name = "LowPassFilter"
-cutoff_hz = 958.0
-resonance = 0.75
-
 [resource]
 bus/1/name = &"Sfx"
 bus/1/solo = false
@@ -25,5 +20,3 @@ bus/2/mute = false
 bus/2/bypass_fx = false
 bus/2/volume_db = 0.0
 bus/2/send = &"Sfx"
-bus/2/effect/0/effect = SubResource("AudioEffectLowPassFilter_j3pel")
-bus/2/effect/0/enabled = true

src/scenes/book_paper.tscn

@@ -1,9 +1,11 @@
 [gd_scene format=3 uid="uid://copkx0vek0okx"]
 
 [ext_resource type="Texture2D" uid="uid://gwy6pqap2ye6" path="res://assets/gfx/ui/page_parchment_small.png" id="1_ttuta"]
+[ext_resource type="Script" uid="uid://b53v027falxj8" path="res://scripts/book_paper.gd" id="2_script"]
 
-[sub_resource type="Animation" id="Animation_ttuta"]
-resource_name = "turn_page"
+[sub_resource type="Animation" id="Animation_reset"]
+resource_name = "RESET"
+length = 0.01
 tracks/0/type = "value"
 tracks/0/imported = false
 tracks/0/enabled = true
@@ -11,22 +13,44 @@ tracks/0/path = NodePath("PagePolygon:polygon")
 tracks/0/interp = 1
 tracks/0/loop_wrap = true
 tracks/0/keys = {
-"times": PackedFloat32Array(),
-"transitions": PackedFloat32Array(),
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
 "update": 0,
-"values": []
+"values": [PackedVector2Array(138, 0, 182, 0, 182, 256, 138, 256, 92, 256, 42, 256, 0, 256, 0, 0, 42, 0, 92, 0)]
+}
+
+[sub_resource type="Animation" id="Animation_ttuta"]
+resource_name = "turn_page"
+length = 0.6
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath("PagePolygon:polygon")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0, 0.075, 0.15, 0.225, 0.3, 0.4, 0.5, 0.6),
+"transitions": PackedFloat32Array(1, 1, 1, 1, 1, 1, 1, 1),
+"update": 0,
+"values": [PackedVector2Array(138, 0, 182, 0, 182, 256, 138, 256, 92, 256, 42, 256, 0, 256, 0, 0, 42, 0, 92, 0), PackedVector2Array(117, 0, 155, 0, 155, 264, 117, 276, 78, 282, 36, 266, 0, 256, 0, 0, 36, 0, 78, 0), PackedVector2Array(76, 0, 100, 0, 100, 278, 76, 311, 51, 328, 23, 284, 0, 256, 0, 0, 23, 0, 51, 0), PackedVector2Array(28, 0, 36, 0, 36, 292, 28, 346, 18, 373, 8, 301, 0, 256, 0, 0, 8, 0, 18, 0), PackedVector2Array(-28, 0, -36, 0, -36, 292, -28, 346, -18, 373, -8, 301, 0, 256, 0, 0, -8, 0, -18, 0), PackedVector2Array(-83, 0, -109, 0, -109, 280, -83, 316, -55, 334, -25, 286, 0, 256, 0, 0, -25, 0, -55, 0), PackedVector2Array(-124, 0, -164, 0, -164, 264, -124, 276, -83, 282, -38, 266, 0, 256, 0, 0, -38, 0, -83, 0), PackedVector2Array(-138, 0, -182, 0, -182, 256, -138, 256, -92, 256, -42, 256, 0, 256, 0, 0, -42, 0, -92, 0)]
 }
 
 [sub_resource type="AnimationLibrary" id="AnimationLibrary_i033y"]
 _data = {
+&"RESET": SubResource("Animation_reset"),
 &"turn_page": SubResource("Animation_ttuta")
 }
 
 [node name="BookPaper" type="Node2D" unique_id=723859984]
+script = ExtResource("2_script")
 
 [node name="PagePolygon" type="Polygon2D" parent="." unique_id=1476858006]
 texture = ExtResource("1_ttuta")
 polygon = PackedVector2Array(138, 0, 182, 0, 182, 256, 138, 256, 92, 256, 42, 256, 0, 256, 0, 0, 42, 0, 92, 0)
+uv = PackedVector2Array(138, 0, 182, 0, 182, 256, 138, 256, 92, 256, 42, 256, 0, 256, 0, 0, 42, 0, 92, 0)
+polygons = [PackedInt32Array(7, 8, 5, 6), PackedInt32Array(8, 9, 4, 5), PackedInt32Array(9, 0, 3, 4), PackedInt32Array(0, 1, 2, 3)]
 
 [node name="AnimationPlayer" type="AnimationPlayer" parent="." unique_id=2024937129]
 libraries/ = SubResource("AnimationLibrary_i033y")
+
+[node name="Camera2D" type="Camera2D" parent="." unique_id=225599989]

src/scenes/paper.tscn

@@ -0,0 +1,60 @@
+[gd_scene load_steps=6 format=3]
+
+[ext_resource type="Shader" path="res://shaders/page_turn.gdshader" id="2_shader"]
+[ext_resource type="Script" path="res://scripts/paper.gd" id="3_script"]
+
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_paper"]
+shader = ExtResource("2_shader")
+shader_parameter/progress = 0.0
+shader_parameter/page_width = 182.0
+shader_parameter/page_height = 256.0
+shader_parameter/arch_amount = 80.0
+
+[sub_resource type="Animation" id="Animation_reset"]
+resource_name = "RESET"
+length = 0.01
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath("PagePoly:material:shader_parameter/progress")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0),
+"transitions": PackedFloat32Array(1),
+"update": 0,
+"values": [0.0]
+}
+
+[sub_resource type="Animation" id="Animation_turn"]
+resource_name = "turn_page"
+length = 2.0
+tracks/0/type = "value"
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/path = NodePath("PagePoly:material:shader_parameter/progress")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/keys = {
+"times": PackedFloat32Array(0, 2.0),
+"transitions": PackedFloat32Array(1, 1),
+"update": 0,
+"values": [0.0, 1.0]
+}
+
+[sub_resource type="AnimationLibrary" id="AnimationLibrary_paper"]
+_data = {
+&"RESET": SubResource("Animation_reset"),
+&"turn_page": SubResource("Animation_turn")
+}
+
+[node name="Paper" type="Node2D"]
+script = ExtResource("3_script")
+
+[node name="PagePoly" type="Polygon2D" parent="."]
+material = SubResource("ShaderMaterial_paper")
+
+[node name="AnimationPlayer" type="AnimationPlayer" parent="."]
+libraries/ = SubResource("AnimationLibrary_paper")
+
+[node name="Camera2D" type="Camera2D" parent="."]

src/scenes/test_spellbook.tscn

@@ -0,0 +1,31 @@
+[gd_scene format=3 uid="uid://dce5khb0f44px"]
+
+[ext_resource type="Script" uid="uid://c75u55osgapks" path="res://scripts/spell_book_ui.gd" id="1_sb"]
+[ext_resource type="Script" uid="uid://cyqdk71cnqipt" path="res://scripts/test_spellbook.gd" id="2_test"]
+
+[node name="TestSpellbook" type="Control" unique_id=1924210192]
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("2_test")
+
+[node name="ColorRect" type="ColorRect" parent="." unique_id=1627853997]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+color = Color(0.12, 0.1, 0.08, 1)
+
+[node name="SpellBookPanel" type="Control" parent="." unique_id=1024751319]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_sb")

src/scripts/book_paper.gd

@@ -0,0 +1,29 @@
+extends Node2D
+## Polygon2D page-turn driven by AnimationPlayer.
+## The "turn_page" animation directly keyframes PagePolygon:polygon vertices.
+## Points 7,6 (spine edge at x=0) never move. All other column pairs fold right-to-left.
+##
+## Column pairs (top, bottom):
+##   Spine (FIXED): pts 7, 6  (x=0)
+##   Col 1:         pts 8, 5  (x=42)
+##   Col 2:         pts 9, 4  (x=92)
+##   Col 3:         pts 0, 3  (x=138)
+##   Col 4:         pts 1, 2  (x=182, leading edge)
+
+@onready var _anim: AnimationPlayer = $AnimationPlayer
+
+
+## Play the page turn animation (right-to-left fold).
+func play_turn() -> void:
+	if _anim:
+		_anim.play("turn_page")
+
+## Play the page turn in reverse (left-to-right unfold).
+func play_turn_reverse() -> void:
+	if _anim:
+		_anim.play_backwards("turn_page")
+
+## Reset to flat (unturned) state immediately.
+func reset_flat() -> void:
+	if _anim:
+		_anim.play("RESET")

src/scripts/book_paper.gd.uid

@@ -0,0 +1 @@
+uid://b53v027falxj8

src/scripts/paper.gd

@@ -0,0 +1,192 @@
+extends Node2D
+## Polygon2D page turn with vertex-shader deformation and front/back side support.
+## Two SubViewports render the front and back page content. The shader switches
+## between them at the midpoint of the turn. Add your content (spell icons,
+## descriptions, etc.) to the returned Control nodes from get_front_content()
+## and get_back_content().
+##
+## Test controls (standalone):
+##   SPACE / ENTER  = play turn
+##   BACKSPACE      = play reverse
+##   R              = reset flat
+
+const GRID_COLS: int = 10
+const GRID_ROWS: int = 8
+
+@onready var _poly: Polygon2D = $PagePoly
+@onready var _anim: AnimationPlayer = $AnimationPlayer
+
+var _front_viewport: SubViewport
+var _back_viewport: SubViewport
+var _front_content: Control
+var _back_content: Control
+var _page_size: Vector2
+
+
+func _ready() -> void:
+	# Get page size from the parchment texture.
+	var parchment: Texture2D = preload("res://assets/gfx/ui/page_parchment_small.png")
+	_page_size = parchment.get_size()
+
+	_setup_viewports(parchment)
+	_build_grid()
+	_setup_test_content()
+	print("Paper scene ready. Press SPACE to turn, BACKSPACE to reverse, R to reset.")
+
+
+func _unhandled_input(event: InputEvent) -> void:
+	if event is InputEventKey and event.pressed and not event.echo:
+		match event.keycode:
+			KEY_SPACE, KEY_ENTER:
+				play_turn()
+			KEY_BACKSPACE:
+				play_turn_reverse()
+			KEY_R:
+				reset_flat()
+
+
+## Play the page turn animation (right-to-left).
+func play_turn() -> void:
+	if _anim:
+		_anim.play("turn_page")
+
+
+## Play the page turn in reverse (left-to-right).
+func play_turn_reverse() -> void:
+	if _anim:
+		_anim.play_backwards("turn_page")
+
+
+## Reset to flat (unturned) state immediately.
+func reset_flat() -> void:
+	if _anim:
+		_anim.play("RESET")
+
+
+## Returns the Control node for the FRONT side. Add children here for front content.
+func get_front_content() -> Control:
+	return _front_content
+
+
+## Returns the Control node for the BACK side. Add children here for back content.
+func get_back_content() -> Control:
+	return _back_content
+
+
+## Create SubViewports for front and back, each with a parchment background.
+func _setup_viewports(parchment: Texture2D) -> void:
+	var w: int = int(_page_size.x)
+	var h: int = int(_page_size.y)
+
+	# --- Front viewport ---
+	_front_viewport = SubViewport.new()
+	_front_viewport.name = "FrontViewport"
+	_front_viewport.size = Vector2i(w, h)
+	_front_viewport.transparent_bg = false
+	_front_viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
+	add_child(_front_viewport)
+
+	var front_bg := TextureRect.new()
+	front_bg.texture = parchment
+	front_bg.stretch_mode = TextureRect.STRETCH_SCALE
+	front_bg.set_anchors_preset(Control.PRESET_FULL_RECT)
+	_front_viewport.add_child(front_bg)
+
+	_front_content = Control.new()
+	_front_content.name = "FrontContent"
+	_front_content.set_anchors_preset(Control.PRESET_FULL_RECT)
+	_front_viewport.add_child(_front_content)
+
+	# --- Back viewport ---
+	_back_viewport = SubViewport.new()
+	_back_viewport.name = "BackViewport"
+	_back_viewport.size = Vector2i(w, h)
+	_back_viewport.transparent_bg = false
+	_back_viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
+	add_child(_back_viewport)
+
+	var back_bg := TextureRect.new()
+	back_bg.texture = parchment
+	back_bg.stretch_mode = TextureRect.STRETCH_SCALE
+	back_bg.set_anchors_preset(Control.PRESET_FULL_RECT)
+	_back_viewport.add_child(back_bg)
+
+	_back_content = Control.new()
+	_back_content.name = "BackContent"
+	_back_content.set_anchors_preset(Control.PRESET_FULL_RECT)
+	_back_viewport.add_child(_back_content)
+
+	# --- Assign textures to the polygon ---
+	_poly.texture = _front_viewport.get_texture()
+
+	var mat: ShaderMaterial = _poly.material as ShaderMaterial
+	if mat:
+		mat.set_shader_parameter("back_texture", _back_viewport.get_texture())
+
+
+## Build a dense polygon grid for smooth vertex-shader deformation.
+func _build_grid() -> void:
+	var page_w: float = _page_size.x
+	var page_h: float = _page_size.y
+
+	# Tell the shader the page dimensions.
+	var mat: ShaderMaterial = _poly.material as ShaderMaterial
+	if mat:
+		mat.set_shader_parameter("page_width", page_w)
+		mat.set_shader_parameter("page_height", page_h)
+
+	var cols: int = GRID_COLS
+	var rows: int = GRID_ROWS
+	var num_verts_x: int = cols + 1
+	var num_verts_y: int = rows + 1
+
+	var verts := PackedVector2Array()
+	var uvs := PackedVector2Array()
+	verts.resize(num_verts_x * num_verts_y)
+	uvs.resize(num_verts_x * num_verts_y)
+
+	for row_i in range(num_verts_y):
+		for col_i in range(num_verts_x):
+			var x: float = (float(col_i) / float(cols)) * page_w
+			var y: float = (float(row_i) / float(rows)) * page_h
+			var idx: int = row_i * num_verts_x + col_i
+			verts[idx] = Vector2(x, y)
+			uvs[idx] = Vector2(x, y)
+
+	_poly.polygon = verts
+	_poly.uv = uvs
+
+	var polys: Array[PackedInt32Array] = []
+	for row_i in range(rows):
+		for col_i in range(cols):
+			var tl: int = row_i * num_verts_x + col_i
+			var tr: int = tl + 1
+			var bl: int = (row_i + 1) * num_verts_x + col_i
+			var br: int = bl + 1
+			polys.append(PackedInt32Array([tl, tr, br, bl]))
+
+	_poly.polygons = polys
+
+	# Center on screen for standalone testing.
+	_poly.position = Vector2(-page_w / 2.0, -page_h / 2.0)
+
+
+## Add test labels so front/back are clearly visible when testing.
+func _setup_test_content() -> void:
+	var front_label := Label.new()
+	front_label.text = "FRONT SIDE"
+	front_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	front_label.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
+	front_label.set_anchors_preset(Control.PRESET_FULL_RECT)
+	front_label.add_theme_font_size_override("font_size", 20)
+	front_label.add_theme_color_override("font_color", Color(0.3, 0.15, 0.05))
+	_front_content.add_child(front_label)
+
+	var back_label := Label.new()
+	back_label.text = "BACK SIDE"
+	back_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	back_label.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
+	back_label.set_anchors_preset(Control.PRESET_FULL_RECT)
+	back_label.add_theme_font_size_override("font_size", 20)
+	back_label.add_theme_color_override("font_color", Color(0.5, 0.1, 0.1))
+	_back_content.add_child(back_label)

src/scripts/paper.gd.uid

@@ -0,0 +1 @@
+uid://y8cle55rlpg2

src/scripts/test_spellbook.gd

@@ -0,0 +1,17 @@
+extends Control
+## Standalone test harness for the SpellBook UI.
+## Run this scene directly (F6) to see the spellbook open and turn pages.
+
+@onready var spell_book: Control = $SpellBookPanel
+
+
+func _ready():
+	# Create a mock CharacterStats with all five spells learnt.
+	var stats := CharacterStats.new()
+	stats.learnt_spells = ["flames", "frostspike", "healing", "water_bubble", "earth_spike"]
+	stats.spell_hotkeys = {"1": "", "2": "", "3": ""}
+
+	# Give the UI one frame to finish _ready(), then feed it the stats.
+	await get_tree().process_frame
+	spell_book.visible = true
+	spell_book.set_character_stats(stats)

src/scripts/test_spellbook.gd.uid

@@ -0,0 +1 @@
+uid://cyqdk71cnqipt

src/shaders/page_turn.gdshader

@@ -0,0 +1,44 @@
+shader_type canvas_item;
+
+// How far the page turn has progressed (0 = flat on right, 1 = flat on left).
+uniform float progress : hint_range(0.0, 1.0) = 0.0;
+
+// Page dimensions in pixels (set from script).
+uniform float page_width = 182.0;
+uniform float page_height = 256.0;
+
+// How many pixels the free edge lifts upward during the turn.
+uniform float arch_amount = 80.0;
+
+// Back side texture (from SubViewport).
+uniform sampler2D back_texture : hint_default_white;
+
+// Pass normalized UV from vertex to fragment for back-texture sampling.
+varying vec2 page_uv;
+
+void vertex() {
+	float nx = VERTEX.x / page_width;
+
+	// Store normalized UV before deformation for texture lookups.
+	page_uv = vec2(VERTEX.x / page_width, VERTEX.y / page_height);
+
+	// --- Horizontal: uniform sweep from right to left ---
+	VERTEX.x *= cos(PI * progress);
+
+	// --- Vertical: page bends upward as it sweeps ---
+	float arch_envelope = sin(PI * progress);
+	float arch_shape = sqrt(nx);
+	float arch = arch_amount * arch_shape * arch_envelope;
+	VERTEX.y -= arch;
+}
+
+void fragment() {
+	if (progress <= 0.5) {
+		// Front side visible.
+		COLOR = texture(TEXTURE, UV);
+	} else {
+		// Page has flipped past mid-point: show back side with mirrored UV.
+		vec2 back_uv = vec2(1.0 - page_uv.x, page_uv.y);
+		COLOR = texture(back_texture, back_uv);
+	}
+}

src/shaders/page_turn.gdshader.uid

@@ -0,0 +1 @@
+uid://bdnrvvdqoocwn