impr(rendering): Machine block casts an ambient occlusion shadow

- Implement the missing ambient occlusion shadow from machine block over neighbour blocks.
- Fix the LightingHelper to properly shade pipes/cables/wires against an opaque block.
- Refactor and cleanup the GT_Block_Machines class of all bad practices and code smell,
  checked and validated with Sonarlint.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/main/java/gregtech/api/GregTech_API.java b/src/main/java/gregtech/api/GregTech_API.java
index 0fbb1cd745..e24297c48c 100644
--- a/src/main/java/gregtech/api/GregTech_API.java
+++ b/src/main/java/gregtech/api/GregTech_API.java
@@ -739,4 +739,23 @@ public class GregTech_API {
         sToolList.add(new GT_ItemStack(GT_Utility.copyAmount(1, aTool)));
         return true;
     }
+
+    /**
+     * Sets the {@link IIconRegister} for Block Icons
+     * @param aIconRegister The {@link IIconRegister} Icon Register
+     */
+    @SideOnly(Side.CLIENT)
+    public static void setBlockIconRegister(IIconRegister aIconRegister) {
+        sBlockIcons = aIconRegister;
+    };
+
+    /**
+     * Sets the {@link IIconRegister} for Items Icons
+     * @param aIconRegister The {@link IIconRegister} Icon Register
+     */
+    @SideOnly(Side.CLIENT)
+    public static void setItemIconRegister(IIconRegister aIconRegister) {
+        GregTech_API.sItemIcons = aIconRegister;
+    }
+
 }