diff --git a/src/shaders/antsCompute.frag b/src/shaders/antsCompute.frag
index 3a319b7..443392a 100644
--- a/src/shaders/antsCompute.frag
+++ b/src/shaders/antsCompute.frag
@@ -337,20 +337,27 @@ void main()	{
             float aheadMatId = texture(tWorld, aheadUv).x;
             int aheadMatInt = int(aheadMatId);
 
+            // food: pick up from any adjacent cell
             if (aheadMatInt == MAT_FOOD) {
                 isCarrying = 1.;
                 cargoMaterialId = aheadMatId;
                 angle += PI;
                 storage = getMaxScentStorage(vUv);
             } else if (aheadMatInt != MAT_AIR && aheadMatInt != MAT_HOME) {
-                vec4 props = texelFetch(uMaterialProps, ivec2(aheadMatInt, 0), 0);
-                float behavior = props.r;
-                float hardness = props.b;
-                if (behavior == BEHAVIOR_POWDER && hardness <= ANT_CARRY_STRENGTH) {
-                    isCarrying = 1.;
-                    cargoMaterialId = aheadMatId;
-                    angle += PI;
-                    storage = getMaxScentStorage(vUv);
+                // powder: don't grab the surface we're walking on — only dig
+                // when facing diagonally into material (DIG priority angles us there)
+                vec2 belowCell = roundUvToCellCenter(pos - vec2(0., cellSize));
+                bool isWalkingSurface = all(equal(aheadUv, belowCell));
+                if (!isWalkingSurface) {
+                    vec4 props = texelFetch(uMaterialProps, ivec2(aheadMatInt, 0), 0);
+                    float behavior = props.r;
+                    float hardness = props.b;
+                    if (behavior == BEHAVIOR_POWDER && hardness <= ANT_CARRY_STRENGTH) {
+                        isCarrying = 1.;
+                        cargoMaterialId = aheadMatId;
+                        angle += PI;
+                        storage = getMaxScentStorage(vUv);
+                    }
                 }
             }
         }