Current particle depth

shaders/CurrentsParticles.gdshader

@@ -1,5 +1,4 @@
 shader_type particles;
-render_mode disable_velocity;
 
 uniform vec3 emissionBoxExtents;
 uniform vec4 colorValue : source_color;
@@ -20,6 +19,8 @@ uniform float brightness;
 const float currentsTimescale = 0.25f;
 const float positionScaling = 0.9f;
 
+uniform float particleDepthVariation = 1.0f;
+
 // Generates a random float and modifies the seed
 float RandFromSeed(inout uint seed) {
     int k;
@@ -55,11 +56,18 @@ void start() {
     TRANSFORM[3].xyz = vec3(RandFromSeed(altSeed) * 2.0 - 1.0, RandFromSeed(altSeed) * 2.0 - 1.0,
         RandFromSeed(altSeed) * 2.0 - 1.0) * emissionBoxExtents;
     TRANSFORM = EMISSION_TRANSFORM * TRANSFORM;
-    float visibleScale = RandFromSeed(altSeed) * 0.75f + 0.625f;
+
+    float backgroundFactor = RandFromSeed(altSeed) * particleDepthVariation;
+    float adjustedBackgroundFactor = pow(backgroundFactor, 3.0f);
+    TRANSFORM[3].y -= adjustedBackgroundFactor * 80.0f;
+    float visibleScale = RandFromSeed(altSeed) * 0.75f + 0.625f
+        + adjustedBackgroundFactor * 35.0f;
+
     TRANSFORM[0].xyz *= visibleScale;
     TRANSFORM[1].xyz *= visibleScale;
     TRANSFORM[2].xyz *= visibleScale;
-    CUSTOM.w = RandFromSeed(altSeed) * 0.2f + 0.8f;
+
+    CUSTOM.w = 1.0f - backgroundFactor * 0.9f;
     CUSTOM.z = gameTime + LIFETIME * 0.5f;
 }
 
@@ -92,12 +100,11 @@ void process() {
         current *= 10.0f * speed;
     }
 
-    VELOCITY = mix(vec3(current.x, 0.0f, current.y), VELOCITY, 1.0f - DELTA * 5.0f);
-
-    TRANSFORM[3].xyz += VELOCITY * DELTA;
+    VELOCITY = mix(VELOCITY, vec3(current.x, 0.0f, current.y), DELTA * 5.0f);
+    VELOCITY *= CUSTOM.w * 0.05f + 0.95f;
 
     vec4 finalColor = colorValue;
-    finalColor.rgb *= CUSTOM.w;
+    finalColor.rgba *= CUSTOM.w;
     finalColor.a *= texture(alphaCurve, vec2(lifetimePercent)).r;
     if (speed != 0.0)
     {

simulation_parameters/microbe_stage/backgrounds.json

@@ -95,8 +95,7 @@
       "res://assets/textures/background/Thrive_vent1.png",
       "res://assets/textures/background/Thrive_vent2.png",
       "res://assets/textures/background/Thrive_vent3.png"
-    ],
-    "ParticleEffect": "res://src/microbe_stage/particles/background/Vent.tscn"
+    ]
   },
   "banana": {
     "Textures": [

simulation_parameters/microbe_stage/biomes.json

@@ -36,7 +36,7 @@
         "r": 0.434,
         "g": 0.505,
         "b": 0.498,
-        "a": 0.75
+        "a": 1.0
       }
     },
     "CompoundCloudBrightness": 1.3,
@@ -230,7 +230,13 @@
       "Speed": 0.6,
       "Chaoticness": 0.5,
       "InverseScale": 1.0,
-      "ParticleCount": 900
+      "ParticleCount": 900,
+      "Colour": {
+        "r": 1.0,
+        "g": 0.49,
+        "b": 0.09,
+        "a": 1
+      }
     },
     "ActiveMusicContexts": [
       "PatchVents"
@@ -757,7 +763,7 @@
         "r": 0.434,
         "g": 0.505,
         "b": 0.498,
-        "a": 0.8
+        "a": 1.0
       }
     },
     "ActiveMusicContexts": [
@@ -1148,7 +1154,13 @@
       "Speed": 0.75,
       "Chaoticness": 0.75,
       "InverseScale": 0.8,
-      "ParticleCount": 1000
+      "ParticleCount": 1000,
+      "Colour": {
+        "r": 0.24,
+        "g": 0.605,
+        "b": 0.776,
+        "a": 1.0
+      }
     },
     "GasVolume": 1,
     "Conditions": {
@@ -1369,7 +1381,13 @@
       "Speed": 0.65,
       "Chaoticness": 0.65,
       "InverseScale": 0.9,
-      "ParticleCount": 800
+      "ParticleCount": 800,
+      "Colour": {
+        "r": 0.035,
+        "g": 0.159,
+        "b": 0.209,
+        "a": 1.0
+      }
     },
     "GasVolume": 1,
     "Conditions": {
@@ -1646,7 +1664,7 @@
         "r": 0.32,
         "g": 0.4,
         "b": 0.39,
-        "a": 0.75
+        "a": 1.0
       }
     },
     "GasVolume": 1,
@@ -1957,7 +1975,7 @@
         "r": 0.434,
         "g": 0.505,
         "b": 0.498,
-        "a": 0.75
+        "a": 1.0
       }
     },
     "CompoundCloudBrightness": 2.5,
@@ -2345,7 +2363,13 @@
       "Speed": 0.5,
       "Chaoticness": 1.0,
       "InverseScale": 1.0,
-      "ParticleCount": 1000
+      "ParticleCount": 1000,
+      "Colour": {
+        "r": 0.544,
+        "g": 0.592,
+        "b": 0.881,
+        "a": 1.0
+      }
     },
     "GasVolume": 1,
     "Conditions": {
@@ -2985,7 +3009,7 @@
         "r": 0.434,
         "g": 0.505,
         "b": 0.498,
-        "a": 0.75
+        "a": 1.0
       }
     },
     "EnvironmentColour": {
@@ -3429,7 +3453,13 @@
       "Speed": 0.75,
       "Chaoticness": 0.75,
       "InverseScale": 0.8,
-      "ParticleCount": 900
+      "ParticleCount": 900,
+      "Colour": {
+        "r": 0.45,
+        "g": 0.7,
+        "b": 0.9,
+        "a": 1.0
+      }
     },
     "GasVolume": 1,
     "Conditions": {
@@ -3876,7 +3906,7 @@
         "r": 0.434,
         "g": 0.505,
         "b": 0.498,
-        "a": 0.5
+        "a": 1.0
       }
     },
     "CompoundCloudBrightness": 2.2,

src/microbe_stage/Background.cs

@@ -11,11 +11,10 @@ public class Background : IRegistryType
     [JsonRequired]
     public List<string> Textures = null!;
 
-    [JsonRequired]
-    public string ParticleEffect = null!;
+    public string? ParticleEffect;
 
     [JsonIgnore]
-    public PackedScene ParticleEffectScene = null!;
+    public PackedScene? ParticleEffectScene;
 
     public string InternalName { get; set; } = null!;
 
@@ -26,12 +25,6 @@ public void Check(string name)
             throw new InvalidRegistryDataException(name, GetType().Name,
                 "Background needs 4 layers");
         }
-
-        if (string.IsNullOrEmpty(ParticleEffect))
-        {
-            throw new InvalidRegistryDataException(name, GetType().Name,
-                "ParticleEffect is missing");
-        }
     }
 
     /// <summary>
@@ -52,8 +45,8 @@ public void Resolve(SimulationParameters parameters)
             }
         }
 #endif
-
-        ParticleEffectScene = GD.Load<PackedScene>(ParticleEffect);
+        if (ParticleEffect != null)
+            ParticleEffectScene = GD.Load<PackedScene>(ParticleEffect);
     }
 
     public void ApplyTranslations()

src/microbe_stage/BackgroundPlane.cs

@@ -133,6 +133,9 @@ public void SetBackground(Background background)
 
         backgroundParticles?.DetachAndQueueFree();
 
+        if (background.ParticleEffectScene == null)
+            return;
+
         backgroundParticles = background.ParticleEffectScene.Instantiate<GpuParticles3D>();
         backgroundParticles.Rotation = Rotation;
         backgroundParticles.LocalCoords = false;

src/microbe_stage/FluidCurrentDisplay.cs

@@ -13,6 +13,7 @@ public partial class FluidCurrentDisplay : GpuParticles3D
     private readonly StringName inverseScaleParameterName = new("inverseScale");
     private readonly StringName brightnessParameterName = new("brightness");
     private readonly StringName colorParameterName = new("colorValue");
+    private readonly StringName particleDepthVariationParameterName = new("particleDepthVariation");
 
 #pragma warning disable CA2213
     [Export]
@@ -79,10 +80,12 @@ public void ApplyBiome(Biome biome)
         if (biome.WaterCurrents.UseTrails)
         {
             DrawPass1 = trailedParticleMesh;
+            material.SetShaderParameter(particleDepthVariationParameterName, 0.0f);
         }
         else
         {
             DrawPass1 = normalParticleMesh;
+            material.SetShaderParameter(particleDepthVariationParameterName, 1.0f);
         }
 
         Amount = biome.WaterCurrents.ParticleCount;
@@ -113,6 +116,7 @@ protected override void Dispose(bool disposing)
             inverseScaleParameterName.Dispose();
             brightnessParameterName.Dispose();
             colorParameterName.Dispose();
+            particleDepthVariationParameterName.Dispose();
         }
 
         base.Dispose(disposing);

src/microbe_stage/FluidCurrentDisplay.tscn

@@ -26,6 +26,7 @@ shader_parameter/speed = 1.0
 shader_parameter/chaoticness = 0.0
 shader_parameter/inverseScale = 1.0
 shader_parameter/brightness = 1.0
+shader_parameter/particleDepthVariation = 1.0
 
 [sub_resource type="StandardMaterial3D" id="StandardMaterial3D_mse0a"]
 transparency = 1