Added CustomBlock#getDrag

src/main/java/net/minestom/server/entity/Entity.java

@@ -413,7 +413,16 @@ public abstract class Entity implements Viewable, EventHandler, DataContainer {
 
                 float drag;
                 if (onGround) {
-                    drag = 0.5f; // ground drag
+                    final BlockPosition blockPosition = position.toBlockPosition();
+                    final CustomBlock customBlock =
+                            instance.getCustomBlock(blockPosition);
+                    if (customBlock != null) {
+                        // Custom drag
+                        drag = customBlock.getDrag(instance, blockPosition);
+                    } else {
+                        // Default ground drag
+                        drag = 0.5f;
+                    }
 
                     // Stop player velocity
                     if (PlayerUtils.isNettyClient(this)) {

src/main/java/net/minestom/server/instance/block/CustomBlock.java

@@ -109,7 +109,7 @@ public abstract class CustomBlock {
      * Can be set to < 0 to be cancelled, in this case vanilla time will be used
      *
      * @param player   the player who is trying to break the block
-     * @param position
+     * @param position the block position
      * @return the time in ms to break it
      */
     public abstract int getBreakDelay(Player player, BlockPosition position);
@@ -195,6 +195,17 @@ public abstract class CustomBlock {
         update(instance, position, blockData);
     }
 
+    /**
+     * Get the drag of this block
+     * <p>
+     * It has to be between 0 and 1
+     *
+     * @return the drag of this block
+     */
+    public float getDrag(Instance instance, BlockPosition blockPosition) {
+        return 0.5f;
+    }
+
     /**
      * Allows custom block to write block entity data to a given NBT compound.
      * Used to send block entity data to the client over the network.