Restore replacing block with cable parts (#1654)

src/main/java/appeng/client/render/previewBlocks/AbstractRendererPreview.java

@@ -9,12 +9,8 @@ import net.minecraftforge.common.util.ForgeDirection;
 
 import org.lwjgl.opengl.GL11;
 
-import appeng.api.implementations.parts.IPartCable;
-import appeng.api.parts.BusSupport;
-import appeng.api.parts.IPart;
 import appeng.api.parts.IPartHost;
 import appeng.core.AEConfig;
-import appeng.parts.networking.PartCable;
 
 public abstract class AbstractRendererPreview {
 
@@ -132,59 +128,32 @@ public abstract class AbstractRendererPreview {
                 .getTileEntity(ViewHelper.getPreviewX(), ViewHelper.getPreviewY(), ViewHelper.getPreviewZ());
 
         if (!(te instanceof IPartHost partHost)) {
-            return true;
+            return !canPlaceBlockAt(
+                    ViewHelper.getWorld(),
+                    ViewHelper.getPreviewX(),
+                    ViewHelper.getPreviewY(),
+                    ViewHelper.getPreviewZ());
         }
 
-        IPart existingPart = partHost.getPart(ViewHelper.getPlacementSide());
-        if (existingPart != null) {
-            return true;
-        }
-
-        IPart centerPart = partHost.getPart(ForgeDirection.UNKNOWN);
-
-        if (centerPart instanceof PartCable cablePart) {
-            BusSupport busSupport = cablePart.supportsBuses();
-            return busSupport != BusSupport.CABLE && busSupport != BusSupport.DENSE_CABLE;
-        }
-
-        return !hasParts(partHost);
+        return !partHost.canAddPart(ViewHelper.getCachedItemStack(), ViewHelper.getPlacementSide());
     }
 
     protected boolean canPlace(World world, ForgeDirection side, int x, int y, int z) {
+        if (!shouldPlaceOnNeighborBlock()) {
+            return true;
+        }
+
         int neighborX = x + side.offsetX;
         int neighborY = y + side.offsetY;
         int neighborZ = z + side.offsetZ;
 
-        TileEntity te = world.getTileEntity(x, y, z);
-        TileEntity neighborTe = world.getTileEntity(neighborX, neighborY, neighborZ);
-        boolean canPlaceOnNeighbor = canPlaceBlockAt(world, neighborX, neighborY, neighborZ);
+        TileEntity te = world.getTileEntity(neighborX, neighborY, neighborZ);
 
-        if (!shouldPlaceOnNeighborBlock() && checkTe(te, side, canPlaceOnNeighbor)) {
-            return true;
-        }
-
-        return checkTe(neighborTe, side, canPlaceOnNeighbor);
-    }
-
-    protected boolean checkTe(TileEntity te, ForgeDirection side, boolean canPlaceOnNeighbor) {
         if (!(te instanceof IPartHost partHost)) {
-            return canPlaceOnNeighbor;
+            return canPlaceBlockAt(world, neighborX, neighborY, neighborZ);
         }
 
-        if (partHost.getPart(side) != null && !shouldPlaceOnNeighborBlock()) {
-            return false;
-        }
-
-        if (partHost.getPart(side.getOpposite()) != null) {
-            return false;
-        }
-
-        IPart centerPart = partHost.getPart(ForgeDirection.UNKNOWN);
-        if (centerPart instanceof IPartCable cable) {
-            return cable.supportsBuses() == BusSupport.CABLE;
-        }
-
-        return hasParts(partHost);
+        return partHost.canAddPart(ViewHelper.getCachedItemStack(), side.getOpposite());
     }
 
     protected void renderBase(double minXBase, double minYBase, double minZBase, double maxXBase, double maxYBase,

src/main/java/appeng/client/render/previewBlocks/RendererCable.java

@@ -108,6 +108,10 @@ public class RendererCable extends AbstractRendererPreview implements IRenderPre
 
     private boolean handleNullTileEntity(boolean isDense, TileEntity neighborTe, World world, ForgeDirection side,
             int x, int y, int z) {
+        if (canPlaceBlockAt(world, x, y, z)) {
+            setPreviewOffset(x, y, z, ForgeDirection.UNKNOWN);
+            return true;
+        }
         setPreviewOffset(x, y, z, side);
         if (neighborTe instanceof IPartHost partHost) {
             IPart centerPart = partHost.getPart(ForgeDirection.UNKNOWN);

src/main/java/appeng/parts/PartPlacement.java

@@ -49,6 +49,7 @@ import appeng.core.sync.packets.PacketPartInteraction;
 import appeng.core.sync.packets.PacketPartPlacement;
 import appeng.core.sync.packets.PacketRequestResync;
 import appeng.facade.IFacadeItem;
+import appeng.fmp.FMPPlacementHelper;
 import appeng.integration.IntegrationRegistry;
 import appeng.integration.IntegrationType;
 import appeng.integration.abstraction.IBuildCraftTransport;
@@ -220,8 +221,8 @@ public class PartPlacement {
 
         IPartHost host = getOrCreateHost(world.getTileEntity(x, y, z), player, side.ordinal());
 
-        // Try to add the part to the target block
-        if (host != null && tryPlace(held, player, world, x, y, z, side, host)) return true;
+        // Try to add the part to the target block, or replace a replaceable block like grass
+        if (tryPlace(held, player, world, x, y, z, side, host)) return true;
 
         // If that didn't work, we try to place on the face of the target block
         int tx = x + side.offsetX;
@@ -236,7 +237,7 @@ public class PartPlacement {
     }
 
     public static boolean tryPlace(ItemStack held, EntityPlayer player, World world, int x, int y, int z,
-            ForgeDirection side, IPartHost host) {
+            ForgeDirection side, @Nullable IPartHost host) {
         final IBlockDefinition multiPart = AEApi.instance().definitions().blocks().multiPart();
         if (!world.canMineBlock(player, x, y, z)) {
             return false;
@@ -271,6 +272,10 @@ public class PartPlacement {
             host = getExistingHost(world.getTileEntity(x, y, z));
             if (host == null) return false;
         }
+        // FMP does not support client side prediction, assume placement is successful on the client side to stop
+        // interaction pipeline on the client side. Item use is the last item in the pipeline, we possibly skip
+        // some offhand client prediction here as well but this only happen when we place on FMP blocks.
+        if (world.isRemote && host instanceof FMPPlacementHelper) return true;
         final ForgeDirection mySide = host.addPart(held, side, player);
         if (mySide != null) {
             if (world.isRemote && host.getPart(mySide) instanceof PartCable cable) {