Clicking on item gives it

buff.h

@@ -18,4 +18,5 @@
 #define BUFF_PUSH_FRONT(buff_ptr, value) { (buff_ptr)->cur_index++; BUFF_VALID(buff_ptr); for(int i = (buff_ptr)->cur_index - 1; i > 0; i--) { (buff_ptr)->data[i] = (buff_ptr)->data[i - 1]; }; (buff_ptr)->data[0] = value; }
 #define BUFF_REMOVE_BACK(buff_ptr) {assert( (buff_ptr)->cur_index > 0); (buff_ptr)->cur_index--;}
 #define BUFF_REMOVE_FRONT(buff_ptr) {if((buff_ptr)->cur_index > 0) {for(int i = 0; i < (buff_ptr)->cur_index - 1; i++) { (buff_ptr)->data[i] = (buff_ptr)->data[i+1]; }; (buff_ptr)->cur_index--;}}
+#define BUFF_REMOVE_AT_INDEX(buff_ptr, index) { BUFF_VALID(buff_ptr); assert(index >= 0); assert(index < (buff_ptr)->cur_index); for(int i = index; i < (buff_ptr)->cur_index - 1; i++) (buff_ptr)->data[i] = (buff_ptr)->data[i + 1]; (buff_ptr)->cur_index -= 1; }
 #define BUFF_CLEAR(buff_ptr) {memset((buff_ptr), 0, sizeof(*(buff_ptr)));  ((buff_ptr)->cur_index = 0);}

main.c

@@ -3806,6 +3806,7 @@ F cost: G + H
     Vec2 item_icon_size = V2(item_icon_width, item_icon_width);
 
     Vec2 cursor = AddV2(grid_aabb.upper_left, V2(padding, -padding));
+    int to_give = -1; // don't modify the item array while iterating
     BUFF_ITER_I(ItemKind, &player->held_items, i)
     {
      Vec2 real_size = LerpV2(item_icon_size, hovered_state[i], MulV2F(item_icon_size, 1.25f));
@@ -3818,7 +3819,17 @@ F cost: G + H
      {
       draw_quad((DrawParams){false, quad_aabb(item_icon), IMG(image_white_square), blendalpha(WHITE, Lerp(0.0f, hovered_state[i], 0.4f)), .layer = LAYER_UI_FG});
       bool hovered = has_point(item_icon, mouse_pos);
-      if(hovered) target = 1.0f;
+      if(hovered)
+      {
+       target = 1.0f;
+       if(pressed.mouse_down)
+       {
+        if(gete(player->talking_to))
+        {
+         to_give = i;
+        }
+       }
+      }
 
       in_screen_space = true;
       dbgrect(item_icon);
@@ -3835,6 +3846,15 @@ F cost: G + H
       cursor.x = grid_aabb.upper_left.x + padding;
      }
     }
+    if(to_give > -1)
+    {
+     choosing_item_grid = false;
+     assert(gete(player->talking_to));
+     ItemKind given_item_kind = player->held_items.data[to_give];
+     BUFF_REMOVE_AT_INDEX(&player->held_items, to_give);
+     BUFF_APPEND(&gete(player->talking_to)->held_items, given_item_kind);
+    }
+
    }
   }