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| − | {{notice|This is '''NOT''' recommended for ''anyone'' to use. It will break at any time. The only non-breaking conversion between love objects and FFI data is via [[Data:getPointer]], which you can cast to a FFI pointer via ffi.cast. The garbage collector may erase the original userdata at any time.}}
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| − | This page details how to convert between löve objects and [http://luajit.org/ext_ffi.html FFI] (Foreign Function Interface) structures.
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| − | Love objects in lua are always stored in a userdata object (Proxy) that contains the object itself, and a type identifier. See the code below for details.
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| − |
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| − | == Function ==
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| − | This function converts a love object into a FFI cdata object. It returns the object itself (not the Proxy object), it's type and type name.
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| − | === Synopsis ===
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| − | <source lang="lua">
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| − | Pointer, Type, TypeEnum = objectToPointer( Object )
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| − | </source>
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| − | === Arguments ===
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| − | {{param|Object|Object|A LÖVE object.}}
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| − | === Returns ===
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| − | {{param|cdata|Pointer|An FFI pointer containing the object's location.}}
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| − | {{param|string|Type|The LÖVE object's type.}}
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| − | {{param|number|TypeEnum|The LÖVE object's type as an enumeration value.}}
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| − |
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| − | == Function ==
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| − | This function converts a FFI cdata object into a Proxy userdata object, it is required to give the type name to assign the metatable to the userdata object, and the type id for the Proxy object.
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| − |
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| − | === Synopsis ===
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| − | <source lang="lua">
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| − | Object = pointerToObject( Pointer, Type, TypeEnum )
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| − | </source>
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| − | === Arguments ===
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| − | {{param|cdata|Pointer|An FFI pointer containing the object's location.}}
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| − | {{param|string|Type|The LÖVE object's type.}}
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| − | {{param|number|TypeEnum|The LÖVE object's type as an enumeration value.}}
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| − | === Returns ===
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| − | {{param|Object|Object|A LÖVE object.}}
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| − |
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| − | == Code ==
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| − | '''<source lang="lua">
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| − | ffi = require("ffi")
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| − |
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| − | ffi.cdef [[
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| − | typedef enum {
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| − | INVALID_ID = 0,
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| − | OBJECT_ID,
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| − | DATA_ID,
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| − | MODULE_ID,
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| − | STREAM_ID,
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| − |
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| − | // Filesystem.
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| − | FILESYSTEM_FILE_ID,
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| − | FILESYSTEM_DROPPED_FILE_ID,
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| − | FILESYSTEM_FILE_DATA_ID,
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| − |
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| − | // Font
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| − | FONT_GLYPH_DATA_ID,
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| − | FONT_RASTERIZER_ID,
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| − |
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| − | // Graphics
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| − | GRAPHICS_DRAWABLE_ID,
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| − | GRAPHICS_TEXTURE_ID,
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| − | GRAPHICS_IMAGE_ID,
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| − | GRAPHICS_QUAD_ID,
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| − | GRAPHICS_FONT_ID,
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| − | GRAPHICS_PARTICLE_SYSTEM_ID,
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| − | GRAPHICS_SPRITE_BATCH_ID,
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| − | GRAPHICS_CANVAS_ID,
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| − | GRAPHICS_SHADER_ID,
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| − | GRAPHICS_MESH_ID,
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| − | GRAPHICS_TEXT_ID,
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| − | GRAPHICS_VIDEO_ID,
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| − |
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| − | // Image
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| − | IMAGE_IMAGE_DATA_ID,
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| − | IMAGE_COMPRESSED_IMAGE_DATA_ID,
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| − |
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| − | // Joystick
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| − | JOYSTICK_JOYSTICK_ID,
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| − |
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| − | // Math
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| − | MATH_RANDOM_GENERATOR_ID,
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| − | MATH_BEZIER_CURVE_ID,
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| − | MATH_COMPRESSED_DATA_ID,
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| − |
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| − | // Audio
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| − | AUDIO_SOURCE_ID,
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| − |
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| − | // Sound
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| − | SOUND_SOUND_DATA_ID,
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| − | SOUND_DECODER_ID,
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| − |
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| − | // Mouse
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| − | MOUSE_CURSOR_ID,
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| − |
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| − | // Physics
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| − | PHYSICS_WORLD_ID,
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| − | PHYSICS_CONTACT_ID,
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| − | PHYSICS_BODY_ID,
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| − | PHYSICS_FIXTURE_ID,
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| − | PHYSICS_SHAPE_ID,
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| − | PHYSICS_CIRCLE_SHAPE_ID,
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| − | PHYSICS_POLYGON_SHAPE_ID,
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| − | PHYSICS_EDGE_SHAPE_ID,
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| − | PHYSICS_CHAIN_SHAPE_ID,
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| − | PHYSICS_JOINT_ID,
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| − | PHYSICS_MOUSE_JOINT_ID,
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| − | PHYSICS_DISTANCE_JOINT_ID,
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| − | PHYSICS_PRISMATIC_JOINT_ID,
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| − | PHYSICS_REVOLUTE_JOINT_ID,
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| − | PHYSICS_PULLEY_JOINT_ID,
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| − | PHYSICS_GEAR_JOINT_ID,
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| − | PHYSICS_FRICTION_JOINT_ID,
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| − | PHYSICS_WELD_JOINT_ID,
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| − | PHYSICS_ROPE_JOINT_ID,
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| − | PHYSICS_WHEEL_JOINT_ID,
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| − | PHYSICS_MOTOR_JOINT_ID,
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| − |
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| − | // Thread
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| − | THREAD_THREAD_ID,
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| − | THREAD_CHANNEL_ID,
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| − |
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| − | // Video
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| − | VIDEO_VIDEO_STREAM_ID,
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| − |
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| − | // The modules themselves. Only add abstracted modules here.
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| − | MODULE_FILESYSTEM_ID,
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| − | MODULE_GRAPHICS_ID,
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| − | MODULE_IMAGE_ID,
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| − | MODULE_SOUND_ID,
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| − |
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| − | // Count the number of bits needed.
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| − | TYPE_MAX_ENUM
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| − | } Type;
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| − |
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| − | typedef struct Object {
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| − | } Object;
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| − |
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| − | typedef struct Proxy {
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| − | Type type;
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| − | Object * object;
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| − | };
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| − | ]]
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| − |
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| − | local conv = {}
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| − |
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| − | function conv.objectToPointer(Object)
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| − | local Proxy = ffi.cast("Proxy *", Object)
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| − | return Proxy.object, tonumber(Proxy.type), Object:type()
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| − | end
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| − |
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| − | function conv.pointerToObject(CData, Type, TypeName)
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| − | local Object = newproxy(true)
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| − | local Metatable = debug.getregistry()[TypeName]
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| − | debug.setmetatable(Object, Metatable)
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| − |
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| − | local Proxy = ffi.cast("Proxy *", Object)
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| − | Proxy.type = Type
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| − | Proxy.object = CData
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| − |
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| − | return Object
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| − | end
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| − |
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| − | return conv
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| − | </source>'''
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| − |
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| − | [[Category:LÖVE]]
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| − | == Other Languages ==
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| − | {{i18n|Conversion between love objects and FFI structures}}
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