Backface culling: Ignore setting in tiledef from old servers.

Outdated servers are always sending tiledefs with culling
enabled no matter what, as the value was previously entirely
ignored.

To compensate, we must (1) detect that we're running against
an old server with a new client, and (2) disable culling for
mesh, plantlike, firelike and liquid draw types no matter what
the server is telling us.

In order to achieve this, we need to bump the protocol version
since we cannot rely on the tiledef version, and test for it
being older. I've bumped the protocol version, although that
should have likely happened in the actual change that introduced
the new backface_culling PR #3578. Fortunately that's only 2
commits back at this point.

We also explicitly test for the drawtype to assure we are not
changing the culling value for other nodes, where it should
remain enabled.

This was tested against various pub servers, including 0.4.13 and
0.4.12.

Fixes #3598

diff --git a/src/network/networkprotocol.h b/src/network/networkprotocol.h
index 674c6810407dd1c1a29bb9cd7a4aa7c9590b8ef6..dc15326d9624cc5e541f6fa066752b7768853bd6 100644 (file)
--- a/src/network/networkprotocol.h
+++ b/src/network/networkprotocol.h
@@ -132,9 +132,12 @@ with this program; if not, write to the Free Software Foundation, Inc.,
                Rename GENERIC_CMD_SET_ATTACHMENT to GENERIC_CMD_ATTACH_TO
        PROTOCOL_VERSION 26:
                Add TileDef tileable_horizontal, tileable_vertical flags
+       PROTOCOL_VERSION 27:
+               backface_culling: backwards compatibility for playing with
+               newer client on pre-27 servers.
 */
 
-#define LATEST_PROTOCOL_VERSION 26
+#define LATEST_PROTOCOL_VERSION 27
 
 // Server's supported network protocol range
 #define SERVER_PROTOCOL_VERSION_MIN 13

diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index 0bcc00e47bab3c5565d7dbb2bccdee4f364c5e68..e30cf6f12f92f0e2d4df2772eb25c1de61dce6b3 100644 (file)
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -139,7 +139,7 @@ void TileDef::serialize(std::ostream &os, u16 protocol_version) const
        }
 }
 
-void TileDef::deSerialize(std::istream &is)
+void TileDef::deSerialize(std::istream &is, bool culling_ignore)
 {
        int version = readU8(is);
        name = deSerializeString(is);
@@ -153,6 +153,11 @@ void TileDef::deSerialize(std::istream &is)
                tileable_horizontal = readU8(is);
                tileable_vertical = readU8(is);
        }
+       // when connecting to old servers - do not use
+       // provided values here since culling needs to be
+       // disabled by default for these drawtypes
+       if (culling_ignore)
+               backface_culling = false;
 }
 
 
@@ -339,15 +344,22 @@ void ContentFeatures::deSerialize(std::istream &is)
                groups[name] = value;
        }
        drawtype = (enum NodeDrawType)readU8(is);
+
+       bool ignore_culling = ((version <= 26) &&
+                       ((drawtype == NDT_MESH) ||
+                        (drawtype == NDT_PLANTLIKE) ||
+                        (drawtype == NDT_FIRELIKE) ||
+                        (drawtype == NDT_LIQUID)));
+
        visual_scale = readF1000(is);
        if(readU8(is) != 6)
                throw SerializationError("unsupported tile count");
        for(u32 i = 0; i < 6; i++)
-               tiledef[i].deSerialize(is);
+               tiledef[i].deSerialize(is, ignore_culling);
        if(readU8(is) != CF_SPECIAL_COUNT)
                throw SerializationError("unsupported CF_SPECIAL_COUNT");
        for(u32 i = 0; i < CF_SPECIAL_COUNT; i++)
-               tiledef_special[i].deSerialize(is);
+               tiledef_special[i].deSerialize(is, ignore_culling);
        alpha = readU8(is);
        post_effect_color.setAlpha(readU8(is));
        post_effect_color.setRed(readU8(is));
@@ -1258,7 +1270,6 @@ void ContentFeatures::serializeOld(std::ostream &os, u16 protocol_version) const
                        "Unsupported version requested");
 }
 
-
 void ContentFeatures::deSerializeOld(std::istream &is, int version)
 {
        if (version == 5) // In PROTOCOL_VERSION 13
@@ -1272,15 +1283,22 @@ void ContentFeatures::deSerializeOld(std::istream &is, int version)
                        groups[name] = value;
                }
                drawtype = (enum NodeDrawType)readU8(is);
+
+               bool ignore_culling = ((version <= 26) &&
+                               ((drawtype == NDT_MESH) ||
+                               (drawtype == NDT_PLANTLIKE) ||
+                               (drawtype == NDT_FIRELIKE) ||
+                               (drawtype == NDT_LIQUID)));
+
                visual_scale = readF1000(is);
                if (readU8(is) != 6)
                        throw SerializationError("unsupported tile count");
                for (u32 i = 0; i < 6; i++)
-                       tiledef[i].deSerialize(is);
+                       tiledef[i].deSerialize(is, ignore_culling);
                if (readU8(is) != CF_SPECIAL_COUNT)
                        throw SerializationError("unsupported CF_SPECIAL_COUNT");
                for (u32 i = 0; i < CF_SPECIAL_COUNT; i++)
-                       tiledef_special[i].deSerialize(is);
+                       tiledef_special[i].deSerialize(is, ignore_culling);
                alpha = readU8(is);
                post_effect_color.setAlpha(readU8(is));
                post_effect_color.setRed(readU8(is));
@@ -1324,12 +1342,12 @@ void ContentFeatures::deSerializeOld(std::istream &is, int version)
                if (readU8(is) != 6)
                        throw SerializationError("unsupported tile count");
                for (u32 i = 0; i < 6; i++)
-                       tiledef[i].deSerialize(is);
+                       tiledef[i].deSerialize(is, drawtype);
                // CF_SPECIAL_COUNT in version 6 = 2
                if (readU8(is) != 2)
                        throw SerializationError("unsupported CF_SPECIAL_COUNT");
                for (u32 i = 0; i < 2; i++)
-                       tiledef_special[i].deSerialize(is);
+                       tiledef_special[i].deSerialize(is, drawtype);
                alpha = readU8(is);
                post_effect_color.setAlpha(readU8(is));
                post_effect_color.setRed(readU8(is));

diff --git a/src/nodedef.h b/src/nodedef.h
index 8f4942c044afe7be31424648ed305a9b6dfa9e5a..182bd09b2c2e600f294b8b7292c6c8ef5e717e2c 100644 (file)
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -137,7 +137,7 @@ struct TileDef
        }
 
        void serialize(std::ostream &os, u16 protocol_version) const;
-       void deSerialize(std::istream &is);
+       void deSerialize(std::istream &is, bool culling_ignore);
 };
 
 enum NodeDrawType