From 43d3e56aeebf500115b7132278265e831b781eda Mon Sep 17 00:00:00 2001
From: Jared Miller <jared@smell.flowers>
Date: Wed, 11 Mar 2026 15:23:03 -0400
Subject: [PATCH] Add material-aware ant pickup with carry strength check

---
 src/shaders/antsCompute.frag | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/shaders/antsCompute.frag b/src/shaders/antsCompute.frag
index b6b902d..c4f7926 100644
--- a/src/shaders/antsCompute.frag
+++ b/src/shaders/antsCompute.frag
@@ -14,7 +14,9 @@ uniform sampler2D tLastExtState;
 uniform sampler2D tWorld;
 uniform sampler2D tPresence;
 uniform float uForagerRatio;
+uniform sampler2D uMaterialProps;
 
+const float ANT_CARRY_STRENGTH = 1.0;
 const float sampleDistance = 20.;
 const float cellSize = 1. / WORLD_SIZE;
 
@@ -88,7 +90,7 @@ void main()	{
     bool wasObstacle = isObstacle(pos);
 
     float personality = lastExtState.r;
-    float cargoQuality = lastExtState.g;
+    float cargoMaterialId = lastExtState.g;
     float pathIntDx = lastExtState.b;
     float pathIntDy = lastExtState.a;
 
@@ -116,7 +118,7 @@ void main()	{
         isCarrying = 0.;
         storage = 0.;
         personality = rand(vUv * 42069.); // 0.0 = pure follower, 1.0 = pure explorer
-        cargoQuality = 0.;
+        cargoMaterialId = 0.;
         pathIntDx = 0.;
         pathIntDy = 0.;
     }
@@ -210,10 +212,28 @@ void main()	{
         angle += PI * (noise - 0.5);
     }
 
-    if (tryGetFood(pos) && isCarrying == 0.) {
-        isCarrying = 1.;
-        angle += PI;
-        storage = getMaxScentStorage(vUv);
+    if (isCarrying == 0.) {
+        float cellMatId = texture(tWorld, roundUvToCellCenter(pos)).x;
+        int cellMatInt = int(cellMatId);
+
+        if (cellMatInt == MAT_FOOD) {
+            // food pickup (existing foraging behavior)
+            isCarrying = 1.;
+            cargoMaterialId = cellMatId;
+            angle += PI;
+            storage = getMaxScentStorage(vUv);
+        } else if (cellMatInt != MAT_AIR && cellMatInt != MAT_HOME) {
+            // check if diggable powder material
+            vec4 props = texelFetch(uMaterialProps, ivec2(cellMatInt, 0), 0);
+            float behavior = props.r;
+            float hardness = props.b;
+            if (behavior == BEHAVIOR_POWDER && hardness <= ANT_CARRY_STRENGTH) {
+                isCarrying = 1.;
+                cargoMaterialId = cellMatId;
+                angle += PI;
+                storage = getMaxScentStorage(vUv);
+            }
+        }
     }
 
     if (tryDropFood(pos)) {
@@ -221,6 +241,7 @@ void main()	{
 
         if (isCarrying == 1.) {
             isCarrying = 0.;
+            cargoMaterialId = 0.;
             angle += PI;
         }
     }
@@ -231,5 +252,5 @@ void main()	{
         angle,
         float((uint(max(storage - SCENT_PER_MARKER, 0.)) << 1) + uint(isCarrying))
     );
-    FragColorExt = vec4(personality, cargoQuality, pathIntDx, pathIntDy);
+    FragColorExt = vec4(personality, cargoMaterialId, pathIntDx, pathIntDy);
 }
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