Implement client node dig prediction

Dig prediction allows clients to remove dug nodes without
waiting for server acknowledgement.
This patch allows mods to override dig prediction,
it can either be turned off or a different "prediction node"
can be selected.

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 6bdb63ef3008b88e7cc743f2c166bef7bfed3780..9a5754368e5c4706a951ec2bb566ee6ceb243dbe 100644 (file)
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -4240,6 +4240,13 @@ Definition tables
           on ground when the player places the item. Server will always update
           actual result to client in a short moment.
         ]]
+        node_dig_prediction = "air",
+        --[[
+        ^ if "", no prediction is made
+        ^ if "air", node is removed
+        ^ Otherwise should be name of node which the client immediately places
+          upon digging. Server will always update actual result shortly.
+        ]]
         sound = {
             breaks = "default_tool_break", -- tools only
             place = --[[<SimpleSoundSpec>]],

diff --git a/src/game.cpp b/src/game.cpp
index 04688e476133633e21cf1897d9d45cb0bb874cc0..d85e34d35a1e1d1f8b247c9323ee4391d5645147 100644 (file)
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -4104,7 +4104,17 @@ void Game::handleDigging(const PointedThing &pointed, const v3s16 &nodepos,
                                        client->getScript()->on_dignode(nodepos, wasnode)) {
                                return;
                        }
-                       client->removeNode(nodepos);
+
+                       const ContentFeatures &f = client->ndef()->get(wasnode);
+                       if (f.node_dig_prediction == "air") {
+                               client->removeNode(nodepos);
+                       } else if (!f.node_dig_prediction.empty()) {
+                               content_t id;
+                               bool found = client->ndef()->getId(f.node_dig_prediction, id);
+                               if (found)
+                                       client->addNode(nodepos, id, true);
+                       }
+                       // implicit else: no prediction
                }
 
                client->interact(2, pointed);

diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index bc03b71e75f361e8ec16a78af0b85a8684e66925..e547e31b131db5b74375ade37727940e9268ec82 100644 (file)
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -335,6 +335,7 @@ void ContentFeatures::reset()
        color = video::SColor(0xFFFFFFFF);
        palette_name = "";
        palette = NULL;
+       node_dig_prediction = "air";
 }
 
 void ContentFeatures::serialize(std::ostream &os, u16 protocol_version) const
@@ -422,6 +423,8 @@ void ContentFeatures::serialize(std::ostream &os, u16 protocol_version) const
        // legacy
        writeU8(os, legacy_facedir_simple);
        writeU8(os, legacy_wallmounted);
+
+       os << serializeString(node_dig_prediction);
 }
 
 void ContentFeatures::correctAlpha(TileDef *tiles, int length)
@@ -530,6 +533,10 @@ void ContentFeatures::deSerialize(std::istream &is)
        // read legacy properties
        legacy_facedir_simple = readU8(is);
        legacy_wallmounted = readU8(is);
+
+       try {
+               node_dig_prediction = deSerializeString(is);
+       } catch(SerializationError &e) {};
 }
 
 #ifndef SERVER

diff --git a/src/nodedef.h b/src/nodedef.h
index 1392e51d41005cfb93d9d905cf35f62930d65f64..853b9bdddeb199025854871b2457dfbbe57afffb 100644 (file)
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -324,6 +324,8 @@ struct ContentFeatures
        // Player cannot build to these (placement prediction disabled)
        bool rightclickable;
        u32 damage_per_second;
+       // client dig prediction
+       std::string node_dig_prediction;
 
        // --- LIQUID PROPERTIES ---
 

diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 9e1fed2f11cc054433db120737ec1584ea7fef7c..ad92741f85797876b1f8ac59fef0a6dcc74fbc9e 100644 (file)
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -737,6 +737,10 @@ ContentFeatures read_content_features(lua_State *L, int index)
        }
        lua_pop(L, 1);
 
+       // Node immediately placed by client when node is dug
+       getstringfield(L, index, "node_dig_prediction",
+               f.node_dig_prediction);
+
        return f;
 }
 
@@ -861,6 +865,8 @@ void push_content_features(lua_State *L, const ContentFeatures &c)
        lua_setfield(L, -2, "legacy_facedir_simple");
        lua_pushboolean(L, c.legacy_wallmounted);
        lua_setfield(L, -2, "legacy_wallmounted");
+       lua_pushstring(L, c.node_dig_prediction.c_str());
+       lua_setfield(L, -2, "node_dig_prediction");
 }
 
 /******************************************************************************/