Activate dormant ants from spawn buffer in shader

src/shaders/antsCompute.frag

@@ -15,6 +15,7 @@ uniform sampler2D tWorld;
 uniform sampler2D tPresence;
 uniform float uForagerRatio;
 uniform sampler2D uMaterialProps;
+uniform vec4 uAntSpawn;
 
 const float ANT_CARRY_STRENGTH = 1.0;
 const float sampleDistance = 20.;
@@ -94,14 +95,43 @@ void main()	{
     int antIndex = int(vUv.y * float(texSize.y)) * texSize.x + int(vUv.x * float(texSize.x));
 
     if (pos == vec2(0)) { // init new ant
-        // only activate ants within the start count
-        if (antIndex >= ANTS_START_COUNT) {
-            // dormant ant — output zeros and skip everything
+        bool spawnRequested = (uAntSpawn.w > 0.5);
+
+        if (antIndex >= ANTS_START_COUNT && !spawnRequested) {
+            // dormant ant, no spawn request — skip
             FragColor = vec4(0);
             FragColorExt = vec4(0);
             return;
         }
 
+        if (antIndex >= ANTS_START_COUNT && spawnRequested) {
+            // probabilistic activation: ~brushRadius ants per frame
+            float activationChance = uAntSpawn.z / float(ANT_BUDGET);
+            float roll = rand(vUv * 50000. + fract(uTime / 1000.));
+            if (roll > activationChance) {
+                // not selected this frame — stay dormant
+                FragColor = vec4(0);
+                FragColorExt = vec4(0);
+                return;
+            }
+            // activate at spawn position with scatter
+            float scatter = uAntSpawn.z / WORLD_SIZE;
+            float rngX = rand(vUv * 10000. + fract(uTime / 1000.));
+            float rngY = rand(vUv * 20000. + fract(uTime / 1000.) + 0.5);
+            pos = vec2(
+                uAntSpawn.x + (rngX - 0.5) * scatter,
+                uAntSpawn.y + (rngY - 0.5) * scatter
+            );
+            pos = clamp(pos, 0., 1.);
+            angle = rand(vUv * 42069.) * 2.0 * PI;
+            isCarrying = 0.;
+            storage = 0.;
+            personality = rand(vUv * 42069.);
+            cargoMaterialId = 0.;
+            pathIntDx = 0.;
+            pathIntDy = 0.;
+        } else {
+            // normal init for starting ants
             #if VIEW_MODE_SIDE
             // spawn on sand surface: random X, scan down from top to find first non-air cell
             float spawnX = rand(vUv * 10000.);
@@ -127,6 +157,7 @@ void main()	{
             pathIntDx = 0.;
             pathIntDy = 0.;
         }
+    }
 
     // --- GRAVITY AND SURFACE CHECK ---
     vec2 cellCenter = roundUvToCellCenter(pos);