Reorder TileLayer. (#5638)

Despite the split of TileSpec into TileDef and TileLayer, the
TileLayer struct is still 66 bytes large, and doesn't fit in
a single cacheline.

I'm moving the color member to cacheline 2, in the hope that it
is less used and the compiler loads all the hot members in a single
cacheline instead. Only color sits now in cacheline 2, all the
other members are in cacheline 1.

Note: is_color is probably rarely set, most nodes will likely
not use hardware coloring, but this may change in the future.
Ideally, this class is shrunk to 64 bytes.

diff --git a/src/client/tile.h b/src/client/tile.h
index c6ebee00621bff812345fff1c9147fb16b66ce2d..15854fb71e19fb7246776b63048adae902cae3af 100644 (file)
--- a/src/client/tile.h
+++ b/src/client/tile.h
@@ -201,8 +201,12 @@ struct TileLayer
 {
        TileLayer():
                texture(NULL),
+               normal_texture(NULL),
+               flags_texture(NULL),
+               shader_id(0),
                texture_id(0),
-               color(),
+               animation_frame_length_ms(0),
+               animation_frame_count(1),
                material_type(TILE_MATERIAL_BASIC),
                material_flags(
                        //0 // <- DEBUG, Use the one below
@@ -210,12 +214,8 @@ struct TileLayer
                        MATERIAL_FLAG_TILEABLE_HORIZONTAL|
                        MATERIAL_FLAG_TILEABLE_VERTICAL
                ),
-               shader_id(0),
-               normal_texture(NULL),
-               flags_texture(NULL),
-               animation_frame_length_ms(0),
-               animation_frame_count(1),
-               has_color(false)
+               has_color(false),
+               color()
        {
        }
 
@@ -286,27 +286,32 @@ struct TileLayer
                        && (material_flags & MATERIAL_FLAG_TILEABLE_VERTICAL);
        }
 
+       // Ordered for size, please do not reorder
+
        video::ITexture *texture;
-       u32 texture_id;
-       /*!
-        * The color of the tile, or if the tile does not own
-        * a color then the color of the node owning this tile.
-        */
-       video::SColor color;
-       // Material parameters
-       u8 material_type;
-       u8 material_flags;
-       u32 shader_id;
        video::ITexture *normal_texture;
        video::ITexture *flags_texture;
 
-       // Animation parameters
+       u32 shader_id;
+
+       u32 texture_id;
+
        u16 animation_frame_length_ms;
        u8 animation_frame_count;
+
+       u8 material_type;
+       u8 material_flags;
+
        //! If true, the tile has its own color.
        bool has_color;
 
        std::vector<FrameSpec> frames;
+
+       /*!
+        * The color of the tile, or if the tile does not own
+        * a color then the color of the node owning this tile.
+        */
+       video::SColor color;
 };
 
 /*!