Revamp underwater title presentation

ui/title_logo_underwater.gdshader

@@ -0,0 +1,48 @@
+shader_type canvas_item;
+
+uniform float horizontal_displacement_pixels : hint_range(0.0, 2.0, 0.25) = 1.5;
+uniform float wave_speed : hint_range(0.0, 2.0, 0.05) = 0.55;
+uniform float wave_scale : hint_range(0.0, 0.20, 0.005) = 0.055;
+uniform vec3 underwater_tint : source_color = vec3(0.78, 0.96, 1.08);
+uniform float tint_strength : hint_range(0.0, 0.35, 0.01) = 0.18;
+uniform float highlight_strength : hint_range(0.0, 0.15, 0.01) = 0.06;
+uniform float bob_amount_pixels : hint_range(0.0, 4.0, 1.0) = 4.0;
+uniform float bob_speed : hint_range(0.0, 2.0, 0.05) = 0.65;
+
+void vertex() {
+	VERTEX.y += round(
+		sin(TIME * bob_speed) * bob_amount_pixels
+	);
+}
+
+void fragment() {
+	float stepped_time = floor(TIME * 12.0) / 12.0;
+	float source_row = floor(UV.y / max(TEXTURE_PIXEL_SIZE.y, 0.000001));
+	float wave = sin(
+		source_row * wave_scale + stepped_time * wave_speed
+	);
+	float pixel_offset = clamp(
+		round(wave * horizontal_displacement_pixels),
+		-2.0,
+		2.0
+	);
+	vec2 sample_uv = UV + vec2(pixel_offset * TEXTURE_PIXEL_SIZE.x, 0.0);
+	vec4 source = texture(TEXTURE, sample_uv);
+
+	vec3 treated_color = mix(
+		source.rgb,
+		source.rgb * underwater_tint,
+		tint_strength
+	);
+	float highlight_wave = sin(
+		UV.y * 26.0 - stepped_time * wave_speed * 0.8
+	) * 0.5 + 0.5;
+	float highlight_level = floor(highlight_wave * 3.0) / 3.0;
+	treated_color += (
+		vec3(0.12, 0.30, 0.34)
+		* highlight_level
+		* highlight_strength
+		* source.a
+	);
+	COLOR = vec4(treated_color, source.a);
+}