assets/shaders/ink_edge.gdshader

@@ -0,0 +1,57 @@
+shader_type spatial;
+render_mode unshaded, fog_disabled, depth_draw_never, depth_test_disabled, cull_disabled;
+
+// Screen-space ink outline: detects depth and normal discontinuities and
+// draws thin dark edges over the scene — the drawn-line pass that unifies
+// every model (kit, hero, character) into the cel look. Attach to a
+// fullscreen quad (POSITION override) so it runs for whatever camera renders.
+
+uniform sampler2D screen_tex : hint_screen_texture, filter_linear;
+uniform sampler2D depth_tex : hint_depth_texture, filter_nearest;
+uniform sampler2D normal_tex : hint_normal_roughness_texture, filter_nearest;
+
+uniform vec4 ink_color : source_color = vec4(0.07, 0.06, 0.09, 1.0);
+uniform float depth_threshold : hint_range(0.0, 4.0) = 1.1;
+uniform float normal_threshold : hint_range(0.0, 1.0) = 0.55;
+uniform float edge_strength : hint_range(0.0, 1.0) = 0.8;
+uniform float max_distance : hint_range(10.0, 500.0) = 220.0;
+
+float linear_depth(vec2 uv, mat4 inv_proj) {
+	float d = texture(depth_tex, uv).r;
+	vec4 ndc = vec4(uv * 2.0 - 1.0, d, 1.0);
+	vec4 view = inv_proj * ndc;
+	return -view.z / view.w;
+}
+
+void vertex() {
+	POSITION = vec4(VERTEX.xy, 1.0, 1.0);
+}
+
+void fragment() {
+	vec2 px = 1.0 / VIEWPORT_SIZE;
+	vec2 uv = SCREEN_UV;
+
+	float dc = linear_depth(uv, INV_PROJECTION_MATRIX);
+	float dl = linear_depth(uv - vec2(px.x, 0.0), INV_PROJECTION_MATRIX);
+	float dr = linear_depth(uv + vec2(px.x, 0.0), INV_PROJECTION_MATRIX);
+	float du = linear_depth(uv - vec2(0.0, px.y), INV_PROJECTION_MATRIX);
+	float dd = linear_depth(uv + vec2(0.0, px.y), INV_PROJECTION_MATRIX);
+
+	// Depth edge: neighbor difference scaled by distance so far geometry
+	// doesn't dissolve into noise.
+	float ddiff = abs(dl - dr) + abs(du - dd);
+	float depth_edge = step(depth_threshold * (0.5 + dc * 0.08), ddiff);
+
+	// Normal edge: crease lines on same-depth corners.
+	vec3 nc = texture(normal_tex, uv).xyz * 2.0 - 1.0;
+	vec3 nl = texture(normal_tex, uv - vec2(px.x, 0.0)).xyz * 2.0 - 1.0;
+	vec3 nu = texture(normal_tex, uv - vec2(0.0, px.y)).xyz * 2.0 - 1.0;
+	float ndiff = length(nc - nl) + length(nc - nu);
+	float normal_edge = step(normal_threshold, ndiff) * step(ddiff, depth_threshold);
+
+	float fade = 1.0 - smoothstep(max_distance * 0.6, max_distance, dc);
+	float edge = max(depth_edge, normal_edge * 0.6) * edge_strength * fade;
+
+	vec3 scene = texture(screen_tex, uv).rgb;
+	ALBEDO = mix(scene, ink_color.rgb, edge);
+}

scenes/maps/level_environment.gd

@@ -34,6 +34,20 @@ static func add_to(level: Node, sky_variant: String = "day") -> WorldEnvironment
 		fill.shadow_enabled = false
 		level.add_child(fill)
 
+	# Screen-space ink edge pass: drawn outlines on every model for whatever
+	# camera renders (fullscreen POSITION-override quad, never culled).
+	if not level.has_node("InkEdgePost"):
+		var ink := MeshInstance3D.new()
+		ink.name = "InkEdgePost"
+		var quad := QuadMesh.new()
+		quad.size = Vector2(2, 2)
+		var ink_mat := ShaderMaterial.new()
+		ink_mat.shader = load("res://assets/shaders/ink_edge.gdshader")
+		quad.material = ink_mat
+		ink.mesh = quad
+		ink.extra_cull_margin = 16384.0
+		level.add_child(ink)
+
 	# Quiet ambient bed so the arena never sits in dead air.
 	if not level.has_node("AmbientBed") and ResourceLoader.exists("res://assets/sounds/wind.wav"):
 		var amb := AudioStreamPlayer.new()