waterpole improvements

assets/shaders/barber_shop.gdshader

@@ -0,0 +1,19 @@
+shader_type spatial;
+render_mode specular_disabled, vertex_lighting;
+
+uniform vec3 color_a : source_color = vec3(1.0);
+uniform vec3 color_b : source_color = vec3(0.0);
+uniform float stripe_count = 2.0;
+uniform float twist_factor = 1.0;
+uniform float speed = 0.5;
+
+void vertex() {
+	float world_height = (MODEL_MATRIX * vec4(VERTEX, 1.0)).y;
+	UV.y = world_height - TIME * speed;
+}
+
+void fragment() {
+	float twisted_x = UV.x - (UV.y * twist_factor);
+	float stripe = step(sin(twisted_x * stripe_count * TAU), 0.0);
+	ALBEDO = mix(color_a, color_b, stripe);
+}