Metaballs

build.sc

@@ -156,4 +156,16 @@ object shaders extends mill.Module {
 
   }
 
+  object shapes extends mill.Module {
+
+    object metaballs extends shadermodule.ShaderModule {
+      val indigoOptions: IndigoOptions =
+        makeIndigoOptions("Metaballs")
+
+      val indigoGenerators: IndigoGenerators =
+        makeIndigoGenerators("generated", "MetaballsConfig", "MetaballsAssets")
+    }
+
+  }
+
 }

shaders/shapes/metaballs/src/Metaballs.scala

@@ -0,0 +1,58 @@
+import indigo.*
+
+import scala.scalajs.js.annotation.*
+import generated.*
+
+@JSExportTopLevel("IndigoGame")
+object Metaballs extends IndigoShader:
+
+  val config: GameConfig =
+    MetaballsConfig.config.noResize
+
+  val assets: Set[AssetType]      = MetaballsAssets.assets.assetSet
+  val channel0: Option[AssetPath] = None
+  val channel1: Option[AssetPath] = None
+  val channel2: Option[AssetPath] = None
+  val channel3: Option[AssetPath] = None
+
+  val shader: Shader =
+    CustomShader.shader
+
+object CustomShader:
+
+  val shader: Shader =
+    UltravioletShader.entityFragment(
+      ShaderId("shader"),
+      EntityShader.fragment[FragmentEnv](fragment, FragmentEnv.reference)
+    )
+
+  import ultraviolet.syntax.*
+
+  @SuppressWarnings(Array("scalafix:DisableSyntax.var"))
+  inline def fragment: Shader[FragmentEnv, Unit] =
+    Shader[FragmentEnv] { env =>
+
+      def N22(p: vec2): vec2 =
+        var a: vec3 = fract(p.xyx * vec3(123.34f, 234.34f, 345.65f))
+        a = a + dot(a, a + 34.45f)
+        fract(vec2(a.x * a.y, a.y * a.z))
+
+      def fragment(color: vec4): vec4 =
+        val uv: vec2 = (2.0f * env.SCREEN_COORDS - env.SIZE) / env.SIZE.y
+
+        var acc: Float = 0.0f
+        val count       = 20.0f
+
+        _for(1.0f, _ < count, _ + 1.0f) { i =>
+          val p: vec2      = sin(N22(vec2(i)) * env.TIME)
+          val distance     = length(uv - p)
+          val blobStrength = 10.0f
+          val radius       = 0.1f
+          val influence    = blobStrength * exp(-distance * distance / (2.0f * radius * radius))
+
+          acc = clamp(acc + (influence / count), 0.0f, 1.0f)
+        }
+
+        vec4(vec3(smoothstep(acc, 0.0f, 0.05f)), 1.0f)
+
+    }