feat: cel-shaded look — toon shader, ink outlines, stylized environment

- toon.gdshader: banded diffuse with cool-tinted shadows (3 tones), stepped
  specular, rim light, and an optional world-triplanar albedo path so level
  geometry keeps the 0.5 m grid with no UVs
- toon_outline.gdshader: inverted-hull ink outline, applied via
  material_overlay so it works on skinned (deforming) meshes
- LevelMaterials: tinted() now returns toon grid materials; toonify()/
  apply_toon_recursive() convert imported character/prop materials in place
- SkinnedPlayerModel: characters get toon shading + outline on load
- LevelEnvironment: shared stylized environment for all maps — saturated
  anime sky, linear tonemap (filmic/ACES crush cel bands), bloom for
  emissives, saturation+contrast grade, light depth haze; test level and
  dust2 now use it and the procedural arena (which had NO environment)
  gets it plus runtime toonification of its baked geometry

Co-Authored-By: Claude Fable 5 <[email protected]>

assets/shaders/toon.gdshader

@@ -0,0 +1,80 @@
+shader_type spatial;
+
+// Cel/toon surface shader used across the game.
+//  - Banded (stepped) diffuse with a tinted shadow color instead of black
+//  - Soft rim light for silhouette pop
+//  - Optional world-space triplanar albedo (level geometry: no UVs needed,
+//    grid stays world-scaled) — otherwise standard UV sampling (characters)
+
+uniform vec4 albedo_color : source_color = vec4(1.0);
+uniform sampler2D albedo_texture : source_color, filter_linear_mipmap, repeat_enable;
+uniform bool has_texture = true;
+uniform bool use_triplanar = false;
+uniform float triplanar_tile = 2.0;      // world units per texture tile
+
+uniform float band_edge : hint_range(-1.0, 1.0) = 0.05;   // NdotL where light band starts
+uniform float band_softness : hint_range(0.001, 0.5) = 0.04;
+uniform float mid_band_edge : hint_range(-1.0, 1.0) = 0.55; // second, brighter band
+uniform vec4 shadow_color : source_color = vec4(0.62, 0.65, 0.78, 1.0); // cool shadow tint
+uniform float rim_strength : hint_range(0.0, 2.0) = 0.35;
+uniform float rim_width : hint_range(0.0, 1.0) = 0.65;
+uniform float specular_strength : hint_range(0.0, 1.0) = 0.25;
+uniform float specular_shininess : hint_range(1.0, 128.0) = 24.0;
+
+varying vec3 world_pos;
+varying vec3 world_normal;
+
+void vertex() {
+	world_pos = (MODEL_MATRIX * vec4(VERTEX, 1.0)).xyz;
+	world_normal = normalize((MODEL_MATRIX * vec4(NORMAL, 0.0)).xyz);
+}
+
+vec3 sample_triplanar(vec3 p, vec3 n) {
+	vec3 w = abs(n);
+	w = pow(w, vec3(4.0));
+	w /= (w.x + w.y + w.z);
+	vec2 uv_x = p.zy / triplanar_tile;
+	vec2 uv_y = p.xz / triplanar_tile;
+	vec2 uv_z = p.xy / triplanar_tile;
+	vec3 cx = texture(albedo_texture, uv_x).rgb;
+	vec3 cy = texture(albedo_texture, uv_y).rgb;
+	vec3 cz = texture(albedo_texture, uv_z).rgb;
+	return cx * w.x + cy * w.y + cz * w.z;
+}
+
+void fragment() {
+	vec3 base = albedo_color.rgb;
+	if (has_texture) {
+		if (use_triplanar) {
+			base *= sample_triplanar(world_pos, world_normal);
+		} else {
+			base *= texture(albedo_texture, UV).rgb;
+		}
+	}
+	ALBEDO = base;
+	ROUGHNESS = 1.0;
+	SPECULAR = 0.0;
+
+	// Rim: brighten grazing angles for that inked-silhouette pop.
+	float rim = 1.0 - clamp(dot(normalize(VIEW), NORMAL), 0.0, 1.0);
+	rim = smoothstep(1.0 - rim_width, 1.0, rim);
+	EMISSION = base * rim * rim_strength;
+}
+
+void light() {
+	float ndotl = dot(NORMAL, LIGHT);
+	// Shadowing folds into the band test so shadow edges band too.
+	float lit = ndotl * ATTENUATION;
+	float band = smoothstep(band_edge - band_softness, band_edge + band_softness, lit);
+	float mid = smoothstep(mid_band_edge - band_softness, mid_band_edge + band_softness, lit);
+	// 3 tones: shadow tint -> base band (0.82) -> full light.
+	float tone = mix(0.82, 1.0, mid);
+	vec3 shade = mix(shadow_color.rgb, vec3(tone), band);
+	DIFFUSE_LIGHT += ALBEDO * LIGHT_COLOR / PI * shade;
+
+	// Stepped specular dot for glossy toon highlights.
+	vec3 h = normalize(VIEW + LIGHT);
+	float spec = pow(clamp(dot(NORMAL, h), 0.0, 1.0), specular_shininess);
+	spec = smoothstep(0.5 - band_softness, 0.5 + band_softness, spec);
+	SPECULAR_LIGHT += LIGHT_COLOR * spec * specular_strength * band;
+}

assets/shaders/toon.gdshader.uid

@@ -0,0 +1 @@
+uid://rm8cyl45cawk

assets/shaders/toon_outline.gdshader

@@ -0,0 +1,17 @@
+shader_type spatial;
+render_mode cull_front, unshaded;
+
+// Inverted-hull outline. Assign as material_overlay on a GeometryInstance3D:
+// the mesh renders a second time, grown along its normals with front faces
+// culled, leaving a colored shell visible only at the silhouette.
+
+uniform vec4 outline_color : source_color = vec4(0.06, 0.05, 0.09, 1.0);
+uniform float outline_width : hint_range(0.0, 0.1) = 0.02;
+
+void vertex() {
+	VERTEX += NORMAL * outline_width;
+}
+
+void fragment() {
+	ALBEDO = outline_color.rgb;
+}

assets/shaders/toon_outline.gdshader.uid

@@ -0,0 +1 @@
+uid://dn2biq23l8yuv

characters/skinned_player_model.gd

@@ -108,6 +108,9 @@ func load_model(path: String) -> void:
 		_pose_mod = ShooterPoseModifier.new()
 		_pose_mod.name = "ShooterPose"
 		skeleton.add_child(_pose_mod)
+
+	# Cel-shaded look: toon shading over the imported textures + ink outline.
+	LevelMaterials.apply_toon_recursive(scene)
 	if animation_player:
 		_index_animations()
 	else:

debug/dust2_level_builder.gd

@@ -7,7 +7,7 @@ func _build_geometry() -> void:
 	var env = get_node_or_null("WorldEnvironment")
 	if env:
 		var environment = env.environment
-		environment.tonemap_mode = Environment.TONE_MAPPER_ACES
+		# (keep the shared linear tonemap — ACES crushes the cel bands)
 		if environment.sky and environment.sky.sky_material:
 			var sky_mat = environment.sky.sky_material
 			sky_mat.sky_top_color = Color(0.3, 0.5, 0.8)

debug/test_level_builder.gd

@@ -96,29 +96,9 @@ func _ramp_static(pos: Vector3, size: Vector3, rot_deg: Vector3, color: Color, n
 # ── Environment ───────────────────────────────────────────────────────────────
 
 func _build_environment() -> void:
-	var env := WorldEnvironment.new()
+	# Shared stylized environment (anime sky, bloom, cel color grade).
-	env.name = "WorldEnvironment"
+	# Also creates the Sun/FillLight pair since none exists yet.
-	var environment := Environment.new()
+	LevelEnvironment.add_to(self)
-	environment.background_mode = Environment.BG_SKY
-	var sky := Sky.new()
-	var sky_mat := ProceduralSkyMaterial.new()
-	sky_mat.sky_top_color = Color(0.15, 0.2, 0.35)
-	sky_mat.sky_horizon_color = Color(0.45, 0.5, 0.65)
-	sky_mat.ground_bottom_color = Color(0.1, 0.08, 0.06)
-	sky_mat.ground_horizon_color = Color(0.35, 0.3, 0.25)
-	sky.sky_material = sky_mat
-	environment.sky = sky
-	environment.ambient_light_source = Environment.AMBIENT_SOURCE_SKY
-	environment.ambient_light_energy = 0.4
-	environment.tonemap_mode = Environment.TONE_MAPPER_FILMIC
-	environment.glow_enabled = true
-	environment.glow_intensity = 0.3
-	environment.glow_bloom = 0.1
-	environment.fog_enabled = true
-	environment.fog_light_color = Color(0.5, 0.55, 0.65)
-	environment.fog_density = 0.002
-	env.environment = environment
-	add_child(env)
 
 
 # ── Floor ─────────────────────────────────────────────────────────────────────
@@ -261,24 +241,9 @@ func _build_target_dummy() -> void:
 # ── Lighting ──────────────────────────────────────────────────────────────────
 
 func _build_lighting() -> void:
-	var sun := DirectionalLight3D.new()
+	# Sun and fill are created by LevelEnvironment.add_to in _build_environment;
-	sun.name = "Sun"
+	# kept as a hook for subclasses that re-style them (see dust2).
-	sun.rotation_degrees = Vector3(-50, 30, 0)
+	pass
-	sun.light_color = Color(1.0, 0.95, 0.85)
-	sun.light_energy = 1.2
-	sun.shadow_enabled = true
-	sun.directional_shadow_mode = DirectionalLight3D.SHADOW_PARALLEL_4_SPLITS
-	sun.directional_shadow_max_distance = 100.0
-	add_child(sun)
-
-	# Fill light (opposite side)
-	var fill := DirectionalLight3D.new()
-	fill.name = "FillLight"
-	fill.rotation_degrees = Vector3(-30, -150, 0)
-	fill.light_color = Color(0.6, 0.7, 0.9)
-	fill.light_energy = 0.3
-	fill.shadow_enabled = false
-	add_child(fill)
 
 
 # ── Player ────────────────────────────────────────────────────────────────────

scenes/maps/level_environment.gd

@@ -0,0 +1,84 @@
+extends Object
+class_name LevelEnvironment
+
+## Shared stylized environment for every level: saturated anime-sky gradient,
+## bloom for emissives (tracers, plasma), and a color grade that pushes the
+## cel-shaded look (high saturation, slight contrast lift). Builders call
+## add_to(level) instead of hand-rolling WorldEnvironment + sun.
+
+
+## Creates and adds a WorldEnvironment + key sun + cool fill light.
+## Returns the WorldEnvironment node.
+static func add_to(level: Node, sky_variant: String = "day") -> WorldEnvironment:
+	var env := WorldEnvironment.new()
+	env.name = "WorldEnvironment"
+	env.environment = make_environment(sky_variant)
+	level.add_child(env)
+
+	if not level.has_node("Sun"):
+		var sun := DirectionalLight3D.new()
+		sun.name = "Sun"
+		sun.rotation_degrees = Vector3(-52, 38, 0)
+		sun.light_color = Color(1.0, 0.97, 0.88)
+		sun.light_energy = 1.4
+		sun.shadow_enabled = true
+		sun.directional_shadow_mode = DirectionalLight3D.SHADOW_PARALLEL_4_SPLITS
+		sun.directional_shadow_max_distance = 120.0
+		level.add_child(sun)
+
+		var fill := DirectionalLight3D.new()
+		fill.name = "FillLight"
+		fill.rotation_degrees = Vector3(-30, -142, 0)
+		fill.light_color = Color(0.6, 0.7, 1.0)
+		fill.light_energy = 0.25
+		fill.shadow_enabled = false
+		level.add_child(fill)
+	return env
+
+
+static func make_environment(sky_variant: String = "day") -> Environment:
+	var environment := Environment.new()
+	environment.background_mode = Environment.BG_SKY
+	var sky := Sky.new()
+	var sky_mat := ProceduralSkyMaterial.new()
+	match sky_variant:
+		"sunset":
+			sky_mat.sky_top_color = Color(0.25, 0.2, 0.5)
+			sky_mat.sky_horizon_color = Color(0.95, 0.6, 0.45)
+			sky_mat.ground_bottom_color = Color(0.18, 0.12, 0.2)
+			sky_mat.ground_horizon_color = Color(0.85, 0.55, 0.45)
+			sky_mat.sun_curve = 0.12
+		_:
+			# Bold anime day sky: deep saturated blue up top, bright cyan horizon.
+			sky_mat.sky_top_color = Color(0.18, 0.4, 0.85)
+			sky_mat.sky_horizon_color = Color(0.72, 0.88, 0.98)
+			sky_mat.ground_bottom_color = Color(0.22, 0.2, 0.24)
+			sky_mat.ground_horizon_color = Color(0.62, 0.7, 0.75)
+			sky_mat.sun_curve = 0.1
+	sky_mat.sun_angle_max = 20.0
+	sky.sky_material = sky_mat
+	environment.sky = sky
+
+	# Flat-ish ambient keeps toon shadow bands readable (sun does the shaping).
+	environment.ambient_light_source = Environment.AMBIENT_SOURCE_SKY
+	environment.ambient_light_energy = 0.55
+
+	# Filmic crushes the cel bands; linear-ish keeps them crisp.
+	environment.tonemap_mode = Environment.TONE_MAPPER_LINEAR
+
+	# Bloom sells emissives (tracers, plasma, rim highlights).
+	environment.glow_enabled = true
+	environment.glow_intensity = 0.5
+	environment.glow_bloom = 0.05
+	environment.glow_hdr_threshold = 1.1
+
+	# Cel color grade: punchy saturation, hint of contrast.
+	environment.adjustment_enabled = true
+	environment.adjustment_saturation = 1.22
+	environment.adjustment_contrast = 1.05
+
+	# A touch of depth haze for scale; far enough to not gray the arena.
+	environment.fog_enabled = true
+	environment.fog_light_color = Color(0.65, 0.75, 0.9)
+	environment.fog_density = 0.0012
+	return environment

scenes/maps/level_environment.gd.uid

@@ -0,0 +1 @@
+uid://cpl4d7ndkc4ft

scenes/maps/level_materials.gd

@@ -1,41 +1,93 @@
 extends Object
 class_name LevelMaterials
 
-## Shared prototype-grid materials for code-built levels.
+## Shared cel-shaded materials for code-built levels and characters.
 ##
-## Every level builder makes its geometry from flat-colored boxes; this gives
+## Level geometry gets the toon shader with world-space triplanar grid
-## them all the same world-space grid surface (0.5 m cells via triplanar
+## (0.5 m cells) tinted per surface; characters get the same toon shading
-## mapping) so speed and distance stay readable at movement-shooter velocity,
+## over their own textures via convert_to_toon(), plus an inverted-hull
-## while keeping each builder's color coding as a tint.
+## outline overlay for the inked silhouette.
 
 const GRID_GRAY := "res://assets/textures/prototype/grid_gray.png"
 const GRID_DARK := "res://assets/textures/prototype/grid_dark.png"
+const TOON_SHADER := "res://assets/shaders/toon.gdshader"
+const OUTLINE_SHADER := "res://assets/shaders/toon_outline.gdshader"
 
 ## One texture tile = 2 m of world, so one grid cell = 0.5 m.
 const WORLD_UNITS_PER_TILE := 2.0
 
 static var _cache: Dictionary = {}
+static var _outline_cache: Dictionary = {}
 
 
-## A tinted grid material. Cached per (tint, dark) so identical surfaces share
+## A tinted toon grid material for level geometry. Cached per (tint, dark) so
-## one material (fewer draw-state changes, and edits apply everywhere).
+## identical surfaces share one material.
-static func tinted(tint: Color, dark: bool = false) -> StandardMaterial3D:
+static func tinted(tint: Color, dark: bool = false) -> Material:
 	var key := "%s|%s" % [tint.to_html(), dark]
 	if _cache.has(key):
 		return _cache[key]
-	var mat := StandardMaterial3D.new()
+	var shader: Shader = load(TOON_SHADER)
+	var mat := ShaderMaterial.new()
+	mat.shader = shader
 	var tex_path := GRID_DARK if dark else GRID_GRAY
 	var tex: Texture2D = load(tex_path) if ResourceLoader.exists(tex_path) else null
 	if tex:
-		mat.albedo_texture = tex
+		mat.set_shader_parameter("albedo_texture", tex)
-		# World triplanar: boxes need no UVs and the grid stays world-scaled.
+		mat.set_shader_parameter("has_texture", true)
-		mat.uv1_triplanar = true
+		mat.set_shader_parameter("use_triplanar", true)
-		mat.uv1_world_triplanar = true
+		mat.set_shader_parameter("triplanar_tile", WORLD_UNITS_PER_TILE)
-		mat.uv1_scale = Vector3.ONE / WORLD_UNITS_PER_TILE
+	else:
+		mat.set_shader_parameter("has_texture", false)
 	# The texture is grayscale ~mid value; multiply by ~2x-brightened tint to
 	# land near the original flat color while keeping the grid contrast.
-	mat.albedo_color = Color(
+	mat.set_shader_parameter("albedo_color", Color(
-		minf(tint.r * 1.9, 1.0), minf(tint.g * 1.9, 1.0), minf(tint.b * 1.9, 1.0))
+		minf(tint.r * 1.9, 1.0), minf(tint.g * 1.9, 1.0), minf(tint.b * 1.9, 1.0)))
-	mat.roughness = 0.85
 	_cache[key] = mat
 	return mat
+
+
+## Toon version of an arbitrary material (usually a character's imported
+## StandardMaterial3D): keeps its albedo texture/color, swaps the shading.
+static func toonify(src: Material) -> Material:
+	var mat := ShaderMaterial.new()
+	mat.shader = load(TOON_SHADER)
+	var tex: Texture2D = null
+	var col := Color.WHITE
+	if src is BaseMaterial3D:
+		tex = src.albedo_texture
+		col = src.albedo_color
+	mat.set_shader_parameter("albedo_texture", tex)
+	mat.set_shader_parameter("has_texture", tex != null)
+	mat.set_shader_parameter("use_triplanar", false)
+	mat.set_shader_parameter("albedo_color", col)
+	# Characters read best with a slightly wider lit band and stronger rim.
+	mat.set_shader_parameter("rim_strength", 0.45)
+	return mat
+
+
+## Swap every mesh surface under `node` to toon shading and add an
+## inverted-hull outline overlay. Safe on skinned meshes (material_overlay
+## re-renders the same deformed mesh).
+static func apply_toon_recursive(node: Node, outline_width: float = 0.015) -> void:
+	if node is MeshInstance3D:
+		var mi := node as MeshInstance3D
+		var surface_count: int = mi.mesh.get_surface_count() if mi.mesh else 0
+		for s in range(surface_count):
+			var src := mi.get_active_material(s)
+			if src and not (src is ShaderMaterial):
+				mi.set_surface_override_material(s, toonify(src))
+		if outline_width > 0.0:
+			mi.material_overlay = outline(outline_width)
+	for child in node.get_children():
+		apply_toon_recursive(child, outline_width)
+
+
+static func outline(width: float = 0.015) -> ShaderMaterial:
+	var key := "%.4f" % width
+	if _outline_cache.has(key):
+		return _outline_cache[key]
+	var mat := ShaderMaterial.new()
+	mat.shader = load(OUTLINE_SHADER)
+	mat.set_shader_parameter("outline_width", width)
+	_outline_cache[key] = mat
+	return mat

scenes/maps/procedural_arena/procedural_arena_runtime.gd

@@ -19,6 +19,16 @@ func _ready() -> void:
 	# Hide mouse
 	Input.mouse_mode = Input.MOUSE_MODE_CAPTURED
 
+	# Cel-shaded presentation: stylized sky/grade + toon materials over the
+	# arena's baked geometry. The scene ships its own DirectionalLight3D;
+	# rename it to Sun so the helper doesn't stack extra suns.
+	var existing_light := get_node_or_null("DirectionalLight3D")
+	if existing_light:
+		existing_light.name = "Sun"
+	if not has_node("WorldEnvironment"):
+		LevelEnvironment.add_to(self)
+	LevelMaterials.apply_toon_recursive(self, 0.0)
+
 	_build_hud()
 	
 	# Multiplayer Spawning