Annotation Type MappedType


  • @Retention(RUNTIME)
    @Target(TYPE)
    public @interface MappedType
    This annotation marks a class as a mapped object, which will go under bytecode transformation at runtime. Mapped objects cannot be instantiated directly; a data buffer must be mapped first and the mapped object instance will then be used as a view on top of the buffer. Instead of a separate instance per "element" in the buffer, only a single instance is used to manage everything. See MappedObject for API details and org.lwjgl.test.mapped.TestMappedObject for examples.

    The instance fields of the annotated class should only be limited to primitive types or ByteBuffer. Static fields are supported and they can have any type.

    The purpose of mapped objects is to reduce the memory requirements required for the type of data that are often used in OpenGL/OpenCL programming, while at the same time enabling clean Java code. There are also performance benefits related to not having to copy data between buffers and Java objects and the removal of bounds checking when accessing buffer data.

    Author:
    Riven
    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      int align
      The mapped data memory alignment, in bytes.
      boolean autoGenerateOffsets
      When autoGenerateOffsets is true, byte offsets of the mapped fields will be generated automatically.
      boolean cacheLinePadding
      When true, SIZEOF will be increased (if necessary) so that it's a multiple of the CPU cache line size.
      int padding
      The number of bytes to add to the total byte size.
    • Element Detail

      • padding

        int padding
        The number of bytes to add to the total byte size. SIZEOF will be calculated as SIZEOF = max(field_offset + field_length) + padding.

        Cannot be used with cacheLinePadding().

        Returns:
        the padding amount
        Default:
        0
      • align

        int align
        The mapped data memory alignment, in bytes.
        Returns:
        the memory alignment
        Default:
        4
      • autoGenerateOffsets

        boolean autoGenerateOffsets
        When autoGenerateOffsets is true, byte offsets of the mapped fields will be generated automatically. This is convenient for packed data. For manually aligned data, autoGenerateOffsets must be set to false and the user needs to manually specify byte offsets using the MappedField annotation.
        Returns:
        true if automatic byte offset generation is required.
        Default:
        true