SDFDisplacement

src/main/java/org/sdoaj/jimgus/util/math/MathHelper.java

@@ -53,6 +53,15 @@ public static float nextFloatAbs(Random random, float min, float max) {
         return nextFloatOne(random) * (max - min) + min;
     }
 
+    public static boolean chance(Random random, float chance) {
+        return random.nextFloat() < chance;
+    }
+
+    public static boolean chance(Random random, float min, float max) {
+        float c = random.nextFloat();
+        return min <= c && c < max;
+    }
+
     public static float toRadians(float degrees) {
         return degrees / 180 * PI;
     }

src/main/java/org/sdoaj/jimgus/util/sdf/operators/SDFDisplacement.java

@@ -0,0 +1,25 @@
+package org.sdoaj.jimgus.util.sdf.operators;
+
+import org.sdoaj.jimgus.util.math.Vec3f;
+
+import java.util.function.Function;
+
+// doesn't really work with some booleans and any SDFs that aren't linear (e.g. SDFLine with no caps)
+public class SDFDisplacement extends SDFUnary {
+    // negative values expand the shape, positive values shrink the shape
+    private Function<Vec3f, Float> displacement;
+
+    public SDFDisplacement setDisplacement(float displacement) {
+        return setDisplacement(pos -> displacement);
+    }
+
+    public SDFDisplacement setDisplacement(Function<Vec3f, Float> displacement) {
+        this.displacement = displacement;
+        return this;
+    }
+
+    @Override
+    public float distance(Vec3f pos) {
+        return this.source.distance(pos) + displacement.apply(pos);
+    }
+}

src/main/java/org/sdoaj/jimgus/world/feature/CloudIslandFeature.java

@@ -11,6 +11,7 @@
 import org.sdoaj.jimgus.util.Util;
 import org.sdoaj.jimgus.util.math.MathHelper;
 import org.sdoaj.jimgus.util.sdf.SDF;
+import org.sdoaj.jimgus.util.sdf.operators.SDFDisplacement;
 import org.sdoaj.jimgus.util.sdf.operators.SDFSubtraction;
 import org.sdoaj.jimgus.util.sdf.operators.SDFTransform;
 import org.sdoaj.jimgus.util.sdf.operators.SDFUnion;
@@ -70,6 +71,13 @@ public boolean place(FeaturePlaceContext<NoneFeatureConfiguration> context) {
         island = new SDFTransform().scale(1, 1, MathHelper.nextFloat(random, 0.5f, 0.8f)).setSource(island);
 
         island.fill(world, cloudPos);
+
+        if (!MathHelper.chance(random, pillarChance)) {
+            return true;
+        }
+
+        // TODO generate pillar
+
         return true;
     }
 }