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homeprevnext XXX - Not complete yet!!!
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homeprevnext Version
    $Date: 1996/11/21 00:52:19 $ $Revision: 1.3 $  
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homeprevnext Dependencies
homeprevnext Overview
    This extension defines an interface which allows static vertex array  
    data to be cached or pre-compiled for more efficient rendering.  This  
    is useful for implementations which can cache the transformed results  
    of array data for reuse by several DrawArrays, ArrayElement, or  
    DrawElements commands.  It is also useful for implementations which  
    can transfer array data to fast memory for more efficient processing.  
    For example, rendering an M by N mesh of quadrilaterals can be  
    accomplished by setting up vertex arrays containing all of the  
    vertexes in the mesh and issuing M DrawElements commands each of  
    which operate on 2 * N vertexes.  Each DrawElements command after  
    the first will share N vertexes with the preceding DrawElements  
    command.  If the vertex array data is locked while the DrawElements  
    commands are executed, then OpenGL may be able to transform each  
    of these shared vertexes just once.  
homeprevnext Issues
    * Is compiled_vertex_array the right name for this extension?  
    * Should there be an implementation defined maximum number of array  
      elements which can be locked at a time (i.e. MAX_LOCKED_ARRAY_SIZE)?  
      Probably not, the lock request can always be ignored with no resulting  
      change in functionality if there are insufficent resources, and allowing  
      the GL to define this limit can make things difficult for applications.  
    * Should there be any restrictions on what state can be changed while  
      the vertex array data is locked?  
      Probably not.  The GL can check for state changes and invalidate  
      any cached vertex state that may be affected.  This is likely to  
      cause a performance hit, so the preferred use will be to not change  
      state while the vertex array data is locked.  
homeprevnext New Procedures and Functions
    void LockArraysEXT (int first, sizei count)  
    void UnlockArraysEXT (void)  
homeprevnext New Tokens
    Accepted by the <pname> parameter of GetBooleanv, GetIntegerv,  
    GetFloatv, and GetDoublev:  
        ARRAY_ELEMENT_LOCK_FIRST_EXT        0x81A8  
        ARRAY_ELEMENT_LOCK_COUNT_EXT        0x81A9  
homeprevnext Additions to Chapter 2 of the 1.1 Specification (OpenGL Operation)
   After the discussion of InterleavedArrays, add a description of  
   array compiling/locking.  
   The currently enabled vertex arrays can be locked with the command  
   LockArraysEXT.  When the vertex arrays are locked, the GL  
   can compile the array data or the transformed results of array  
   data associated with the currently enabled vertex arrays.  The  
   vertex arrays are unlocked by the command UnlockArraysEXT.  
   Between LockArraysEXT and UnlockArraysEXT the application  
   should ensure that none of the array data in the range of  
   elements specified by <first> and <count> are changed.  
   Changes to the array data between the execution of LockArraysEXT  
   and UnlockArraysEXT commands may affect calls may affect DrawArrays,  
   ArrayElement, or DrawElements commands in non-sequential ways.  
   While using a compiled vertex array, references to array elements  
   by the commands DrawArrays, ArrayElement, or DrawElements which are  
   outside of the range specified by <first> and <count> are undefined.  
homeprevnext Additions to Chapter 3 of the 1.1 Specification (Rasterization)
homeprevnext Additions to Chapter 4 of the 1.1 Specification (Per-Fragment Operations and the Frame Buffer)
homeprevnext Additions to Chapter 5 of the 1.1 Specification (Special Functions)
    LockArraysEXT and UnlockArraysEXT are not complied into display lists  
    but are executed immediately.  
homeprevnext Additions to Chapter 6 of the 1.1 Specification (State and State Requests)
homeprevnext Additions to the GLX Specification
    XXX - Not complete yet!!!  
homeprevnext GLX Protocol
    XXX - Not complete yet!!!  
homeprevnext Errors
    INVALID_VALUE is generated if LockArrarysEXT parameter <first> is less  
    than zero.  
    INVALID_VALUE is generated if LockArraysEXT parameter <count> is less than  
    or equal to zero.  
    INVALID_OPERATION is generated if LockArraysEXT is called between execution  
    of LockArraysEXT and corresponding execution of UnlockArraysEXT.  
    INVALID_OPERATION is generated if UnlockArraysEXT is called without a  
    corresponding previous execution of LockArraysEXT.  
    INVALID_OPERATION is generated if LockArraysEXT or UnlockArraysEXT is called  
    between execution of Begin and the corresponding execution of End.  
homeprevnext New State
    Get Value                           Get Command     Type    Value   Attrib  
    ---------                           -----------     ----    ------- ------  
    ARRAY_ELEMENT_LOCK_FIRST_EXT        GetIntegerv     Z+      0       client-vertex-array  
    ARRAY_ELEMENT_LOCK_COUNT_EXT        GetIntegerv     Z+      0       client-vertex-array  
homeprevnext New Implementation Dependent State
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