feat: implement environment effects in a more correct way

SSAO and skylight are affected by cloud-coverage.

Clouds are not as strongly affected by a bright skylight (change in shader), therefore lights are stronger in general (bluer sky).

Refs: #312

World/Environment/WorldEnvironment.gd

@@ -1,19 +1,22 @@
 extends WorldEnvironment
 
-@onready var light = get_node("DirectionalLight3D")
+# Diffuse and specular
+@onready var light: DirectionalLight3D = get_node("DirectionalLight")
+# Ambient and sky
+@onready var sky_light: DirectionalLight3D = get_node("DirectionalLight/SkyLight")
 
 var wind_speed = 0
 var wind_direction = 0
 
-var brightest_light_energy = 0.75
+var brightest_light_energy = 1.5
 var light_darken_begin_altitude = 15.0
 var light_disabled_altitude = 3.0
 
 
 func apply_visibility(new_visibility):
-	environment.fog_density = new_visibility * 0.000008
-	environment.volumetric_fog_enabled = new_visibility > 40
-	environment.volumetric_fog_density = new_visibility * 0.0003
+	environment.fog_density = remap(new_visibility, 0., 100., 0, 0.00015)
+	# Enable volumetric fog only above a certain threshold
+	environment.volumetric_fog_density = remap(new_visibility, 30., 100., 0.0, 0.045)
 
 
 func apply_rain_enabled(enabled: bool):
@@ -62,20 +65,29 @@ func apply_datetime(datetime: Dictionary):
 
 
 func apply_light_energy():
-	var altitude = rad_to_deg(-light.rotation.x)
+	# Directional light energy is 0 when cloud coverage is maximized
+	var cloud_coverage = environment.sky.get_material().get_shader_parameter("cloud_coverage")
+	var directional_energy = brightest_light_energy - remap(cloud_coverage, 0, 1, 0, brightest_light_energy)
 
-	# Light energy is halved when it is maximally cloudy
-	var brightest = brightest_light_energy - environment.sky.get_material().get_shader_parameter("cloud_coverage") * 0.000025
+	# Lower light quickly in the beginning when coverage/density are higher
+	# and lower light slower in the end (sqrt-curve-function), vice versa for ssao
+	var sqrt_cloud_cov = sqrt(cloud_coverage)
+	sky_light.light_energy = 4.0 - remap(sqrt_cloud_cov, 0, 1, 0, 2)
+	environment.ssao_intensity = 3.0 + remap(sqrt_cloud_cov, 0, 1, 0, 5)
 
+	var altitude = rad_to_deg(-light.rotation.x)
+	# Sunrise/sunset
 	if altitude > light_disabled_altitude and altitude < light_darken_begin_altitude:
-		_set_light_energy(inverse_lerp(light_disabled_altitude, light_darken_begin_altitude, altitude) * brightest)
+		_set_directional_light_energy(directional_energy * 
+			inverse_lerp(light_disabled_altitude, light_darken_begin_altitude, altitude))
+	# Night
 	elif altitude <= light_disabled_altitude:
-		_set_light_energy(0.0)
+		_set_directional_light_energy(0.0)
 	else:
-		_set_light_energy(brightest)
+		_set_directional_light_energy(directional_energy)
 
 
-func _set_light_energy(new_energy):
+func _set_directional_light_energy(new_energy):
 	light.light_energy = new_energy
 
 

World/Environment/WorldEnvironment.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=12 format=3 uid="uid://cejf5c8oyb02b"]
+[gd_scene load_steps=13 format=3 uid="uid://cejf5c8oyb02b"]
 
 [ext_resource type="Script" path="res://World/Environment/WorldEnvironment.gd" id="1"]
 [ext_resource type="Shader" path="res://addons/clouds/clouds.gdshader" id="1_p31xn"]
@@ -10,10 +10,10 @@
 
 [sub_resource type="ShaderMaterial" id="ShaderMaterial_ywyjs"]
 shader = ExtResource("1_p31xn")
-shader_parameter/_density = 0.05
+shader_parameter/_density = 0.069
 shader_parameter/cloud_coverage = 0.25
 shader_parameter/_time_scale = 1.0
-shader_parameter/_time_offset = 0.0
+shader_parameter/_time_offset = 80.0
 shader_parameter/rayleigh = 2.0
 shader_parameter/rayleigh_color = Color(0.26, 0.41, 0.58, 1)
 shader_parameter/mie = 0.005
@@ -32,40 +32,49 @@ sky_material = SubResource("ShaderMaterial_ywyjs")
 
 [sub_resource type="Environment" id="2"]
 background_mode = 2
-background_energy_multiplier = 1.5
 sky = SubResource("Sky_gjwmw")
 ambient_light_source = 3
-ambient_light_color = Color(1, 1, 1, 1)
 reflected_light_source = 2
 tonemap_white = 6.0
+ssao_enabled = true
+ssao_radius = 5.0
+ssao_intensity = 6.15
 sdfgi_min_cell_size = 1.0
 sdfgi_cascade0_distance = 64.0
 sdfgi_max_distance = 1024.0
 glow_enabled = true
 fog_enabled = true
 fog_light_color = Color(0.517647, 0.552941, 0.607843, 1)
-fog_density = 0.001
+fog_density = 0.0119
 fog_aerial_perspective = 1.0
 fog_sky_affect = 0.0
+fog_height_density = 2.0
 volumetric_fog_enabled = true
+volumetric_fog_density = 0.0
 adjustment_contrast = 1.15
 adjustment_saturation = 1.2
 
 [sub_resource type="SphereMesh" id="SphereMesh_v0nf7"]
 
+[sub_resource type="QuadMesh" id="QuadMesh_l7xtl"]
+size = Vector2(2, 2)
+
 [node name="WorldEnvironment" type="WorldEnvironment"]
 environment = SubResource("2")
 script = ExtResource("1")
 
-[node name="DirectionalLight3D" type="DirectionalLight3D" parent="."]
-transform = Transform3D(-2.91845e-08, -0.744463, 0.667664, -3.25415e-08, 0.667664, 0.744463, -1, 1.24345e-14, -4.37114e-08, 0, 0, 0)
+[node name="DirectionalLight" type="DirectionalLight3D" parent="."]
+transform = Transform3D(0.551073, -0.830715, 0.0789348, -0.498894, -0.252165, 0.829167, -0.668897, -0.496311, -0.5534, 0, 0, 0)
 layers = 15
+light_energy = 1.5
 shadow_enabled = true
 directional_shadow_blend_splits = true
 directional_shadow_max_distance = 1000.0
 sky_mode = 1
 
-[node name="DirectionalLight3D" type="DirectionalLight3D" parent="DirectionalLight3D"]
+[node name="SkyLight" type="DirectionalLight3D" parent="DirectionalLight"]
+transform = Transform3D(0.998675, 0.0390908, -0.0334572, -0.0374992, 0.998193, 0.0469456, 0.0352319, -0.0456288, 0.998337, 0, 0, 0)
+light_energy = 4.0
 sky_mode = 2
 
 [node name="MeshInstance3D" type="MeshInstance3D" parent="."]
@@ -76,3 +85,6 @@ enabled = false
 
 [node name="Lightning" parent="." instance=ExtResource("7_canqr")]
 enabled = false
+
+[node name="MeshInstance3D2" type="MeshInstance3D" parent="."]
+mesh = SubResource("QuadMesh_l7xtl")

addons/clouds/clouds.gdshader

@@ -167,7 +167,7 @@ vec4 march(vec3 pos,  vec3 end, vec3 dir, int depth) {
 	vec3 p = pos + hash(pos * 10.0) * ss;
 	const float t_dist = sky_t_radius-sky_b_radius;
 	float lss = (t_dist / 36.0);
-	vec3 ldir = normalize(LIGHT0_DIRECTION);
+	vec3 ldir = normalize(LIGHT0_DIRECTION) * 0.6;
 	vec3 L = vec3(0.0);
 	int count=0;
 	float t = 1.0;