Add null check bug fix

Author: akerfel

Minecraft2D/Functions.pde

@@ -35,9 +35,6 @@ void makeViewDistanceFitZoomLevel() {
     setViewDistance(numBlocksVisible + 4);
 }
 
-// This function is called each frame.
-// I tried to only call this each time the state.player stepped on a new block, but it did not seem to improve the fps.
-// That also introduced other problems (block would not be mined until stepped new block), so I chose to keep it like this.
 void loadVisibleBlocks() {
     for (int x = 0; x < settings.viewDistance; x++) {
         for (int y = 0; y < settings.viewDistance; y++) {

Minecraft2D/Player.pde

@@ -115,7 +115,7 @@ public class Player extends Body {
 
     boolean selectedItemIsBlock() {
         ItemSlot slot = getSelectedItemSlot();   
-        return slot.item.itemType == ItemType.BLOCK;
+        return slot.item != null && slot.item.itemType == ItemType.BLOCK;
     }
 
     ItemSlot getSelectedItemSlot() {