Added starfield sky

levels/ghost_ship/environment_3.tres

@@ -1,12 +1,24 @@
-[gd_resource type="Environment" load_steps=3 format=3 uid="uid://bkvij3ljl5ox3"]
+[gd_resource type="Environment" load_steps=4 format=3 uid="uid://bkvij3ljl5ox3"]
 
-[sub_resource type="ProceduralSkyMaterial" id="ProceduralSkyMaterial_hhk8i"]
+[ext_resource type="Shader" uid="uid://ckw76htb0608r" path="res://levels/ghost_ship/starfield.gdshader" id="1_7hdi4"]
+
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_7hdi4"]
+shader = ExtResource("1_7hdi4")
+shader_parameter/sky_color = Color(0.05, 0.065, 0.1, 1)
+shader_parameter/star_base_color = Color(0.926333, 1, 0.74, 1)
+shader_parameter/star_hue_offset = 0.434
+shader_parameter/star_intensity = 0.05
+shader_parameter/star_twinkle_speed = 0.1
+shader_parameter/star_twinkle_intensity = 0.2
+shader_parameter/layer_scale = 30.0
+shader_parameter/layer_scale_step = 10.0
+shader_parameter/layers_count = 1
 
 [sub_resource type="Sky" id="Sky_7hdi4"]
-sky_material = SubResource("ProceduralSkyMaterial_hhk8i")
+sky_material = SubResource("ShaderMaterial_7hdi4")
 
 [resource]
-background_mode = 1
+background_mode = 2
 sky = SubResource("Sky_7hdi4")
 ambient_light_source = 2
 ambient_light_color = Color(0.427493, 0.427493, 0.427493, 1)
@@ -27,7 +39,7 @@ volumetric_fog_density = 0.1
 volumetric_fog_albedo = Color(0.101961, 0.0666667, 0, 1)
 volumetric_fog_emission = Color(0.101961, 0.0156863, 0, 1)
 volumetric_fog_emission_energy = 0.3
-volumetric_fog_sky_affect = 0.1
+volumetric_fog_sky_affect = 0.0
 adjustment_enabled = true
 adjustment_contrast = 1.1
 adjustment_saturation = 1.3

levels/ghost_ship/starfield.gdshader

@@ -0,0 +1,113 @@
+shader_type sky;
+
+// Comment this if you don't want to use star twinke. However, if you do want to keep it,
+// I suggest you to set the sky process mode to High-Quality Incremental or Real-Time,
+// as star twinkling may greatly impact performance.
+#define USE_TWINKLE
+
+group_uniforms sky;
+uniform vec3 sky_color: source_color = vec3(0.03, 0.05, 0.11);
+
+group_uniforms stars;
+uniform vec3 star_base_color: source_color = vec3(0.8, 1.0, 0.3);
+uniform float star_hue_offset: hint_range(0., 1.) = 0.6;
+uniform float star_intensity: hint_range(0., 0.2) = 0.08;
+#ifdef USE_TWINKLE
+uniform float star_twinkle_speed: hint_range(0.0, 2.0) = 0.8;
+uniform float star_twinkle_intensity: hint_range(0.0, 1.0) = 0.2;
+#endif
+
+group_uniforms layers;
+uniform float layer_scale: hint_range(0., 60.) = 20.;
+uniform float layer_scale_step: hint_range(0., 40.) = 10.;
+uniform int layers_count: hint_range(0, 12) = 3;
+
+// Hue credit:
+// The MIT License
+// Copyright © 2024 DigvijaysinhGohil
+// https://github.com/DigvijaysinhGohil/Godot-Shader-Lib
+
+vec3 hue(vec3 input, float offset, int range_index) {
+	// RGB to HSV
+	vec4 k = vec4(0., -1./3., 2./3., -1.);
+	vec4 p = mix(vec4(input.bg, k.wz), vec4(input.gb, k.xy), step(input.b, input.g));
+	vec4 q = mix(vec4(p.xyw, input.r), vec4(input.r, p.yzx), step(p.x, input.r));
+	float d = q.x - min(q.w, q.y);
+	float e = 1.e-10;
+	vec3 hsv = vec3(abs(q.z + (q.w - q.y) / (6. * d + e)), d / (q.x + e), q.x);
+
+	offset = (range_index == 0) ? offset / 360. : offset;
+	float hue = hsv.x + offset;
+	if (hue < 0.) {
+		hsv.x = hue + 1.;
+	} else if (hue > 1.) {
+		hsv.x = hue - 1.;
+	} else {
+		hsv.x = hue;
+	}
+
+	// HSV to RGB
+	vec4 k2 = vec4(1., 2./3., 1./3., 3.);
+	vec3 p2 = abs(fract(hsv.xxx + k2.xyz) * 6. - k2.www);
+	vec3 rgb = hsv.z * mix(k2.xxx, clamp(p2 - k2.xxx, 0., 1.), hsv.y);
+	return rgb;
+}
+
+// Voronoi method credit:
+// The MIT License
+// Copyright © 2013 Inigo Quilez
+// https://www.shadertoy.com/view/ldl3Dl
+
+vec3 hash(vec3 x) {
+	x = vec3(dot(x, vec3(127.1,311.7, 74.7)),
+			 dot(x, vec3(269.5,183.3,246.1)),
+			 dot(x, vec3(113.5,271.9,124.6)));
+	return fract(sin(x) * 43758.5453123);
+}
+
+vec2 voronoi(in vec3 x){
+	vec3 p = floor(x);
+	vec3 f = fract(x);
+
+	float res = 100.;
+	float id = 0.;
+
+	for (float k = -1.; k <= 1.; k += 1.) {
+		for (float j = -1.; j <= 1.; j += 1.) {
+			for (float i = -1.; i <= 1.; i += 1.) {
+				vec3 b = vec3(i, j, k);
+				vec3 r = vec3(b) - f + hash(p + b);
+				float d = dot(r, r);
+				if (d < res) {
+					res = d;
+					id = dot(p + b, vec3(0., 57., 113.));
+				}
+		    }
+		}
+	}
+
+	return vec2(sqrt(res), id);
+}
+
+void sky() {
+	COLOR = sky_color;
+
+	for (int i = 0; i < layers_count; i++) {
+		vec3 pos = EYEDIR * (layer_scale + float(i) * layer_scale_step);
+		vec2 layer = voronoi(pos);
+
+		vec3 rand = hash(vec3(layer.y));
+
+		#ifdef USE_TWINKLE
+			float twinkle = sin(TIME * PI * star_twinkle_speed + rand.x * TAU);
+			twinkle *= star_twinkle_intensity;
+			float star = smoothstep(star_intensity + star_intensity * twinkle, 0., layer.x);
+		#else
+			float star = smoothstep(star_intensity, 0., layer.x);
+		#endif
+
+		vec3 star_color = star * hue((COLOR + star_base_color), rand.y * star_hue_offset, 1);
+
+		COLOR += star_color;
+	}
+}

levels/ghost_ship/starfield.gdshader.uid

@@ -0,0 +1 @@
+uid://ckw76htb0608r