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GL_NV_light_max_exponent
homeprevnext Name
  
    NV_light_max_exponent  
  
homeprevnext Name Strings
  
    GL_NV_light_max_exponent  
  
homeprevnext Contact
  
    Mark J. Kilgard, NVIDIA Corporation (mjk 'at' nvidia.com)  
  
homeprevnext Notice
  
    Copyright NVIDIA Corporation, 1999, 2000.  
  
homeprevnext Status
  
    Shipping (version 1.0)  
  
homeprevnext Version
  
    May 20, 2000  
    $Date$ $Revision$  
  
homeprevnext Number
  
    189  
  
homeprevnext Dependencies
  
    None  
  
homeprevnext Overview
  
    Default OpenGL does not permit a shininess or spot exponent over  
    128.0.  This extension permits implementations to support and  
    advertise a maximum shininess and spot exponent beyond 128.0.  
  
    Note that extremely high exponents for shininess and/or spot light  
    cutoff will require sufficiently high tessellation for acceptable  
    lighting results.  
  
    Paul Deifenbach's thesis suggests that higher exponents are  
    necessary to approximate BRDFs with per-vertex ligthing and  
    multiple passes.  
  
homeprevnext New Procedures and Functions
  
    None  
  
homeprevnext New Tokens
  
    Accepted by the <pname> parameters of GetBooleanv, GetIntegerv,  
    GetFloatv, and GetDoublev:  
  
        MAX_SHININESS_NV                  0x8504  
        MAX_SPOT_EXPONENT_NV              0x8505  
  
homeprevnext Additions to Chapter 2 of the GL Specification (OpenGL Operation)
  
    In Table 2.7, change the srm range entry to read:  
  
    "(range: [0.0, value of MAX_SHININESS_NV])"  
  
    In Table 2.7, change the srli range entry to read:  
  
    "(range: [0.0, value of MAX_SPOT_EXPONENT_NV])"  
  
    Add to the end of the second paragraph in Section 2.13.2:  
  
    "The values of MAX_SHININESS_NV and MAX_SPOT_EXPONENT_NV are  
    implementation dependent, but must be equal or greater than 128."  
  
homeprevnext Additions to Chapter 3 of the GL Specification (Rasterization)
  
    None  
  
homeprevnext Additions to Chapter 4 of the GL Specification (Per-Fragment Operations and the Framebuffer)
  
    None.  
  
homeprevnext Additions to Chapter 5 of the GL Specification (Special Functions)
  
    None  
  
homeprevnext Additions to Chapter 6 of the GL Specification (State and State Requests)
  
    None  
  
homeprevnext Additions to the GLX Specification
  
    None  
  
homeprevnext GLX Protocol
  
    None  
  
homeprevnext Errors
  
    INVALID_VALUE is generated by Material if enum is SHININESS and the  
    shininess param is greater than the MAX_SHININESS_NV.  
  
    INVALID_VALUE is generated by Material if enum is SPOT_EXPONENT and  
    the shininess param is greater than the MAX_SPOT_EXPONENT_NV.  
  
homeprevnext New State
  
    None.  
  
homeprevnext New Implementation Dependent State
  
(table 6.24, p214) add the following entries:  
  
    Get Value                     Type    Get Command   Minimum Value   Description         Sec     Attribute  
    ---------------------------   ----    -----------   -------------   -----------------   ------  --------------  
    MAX_SHININESS_NV              Z+      GetIntegerv   128             Maximum             2.13.2  -  
                                                                        shininess for  
                                                                        specular lighting  
    MAX_SPOT_EXPONENT_NV          Z+      GetIntegerv   128             Maximum             2.13.2  -  
                                                                        exponent for  
                                                                        spot lights  
  
NVIDIA Implementation Details  
  
    NVIDIA's Release 4 drivers incorrectly and accidently advertised this  
    extension with an "EXT" prefix instead of an "NV" prefix.  Release 5  
    and later drivers correctly advertise this extension with an "NV"  
    extension.  
  
homeprevnext Revision History
  
    5/20/00 - earlier versions of this specification had the incorrect  
    enumerant values which did not match NVIDIA's driver implementation.  
    enumerant values which did not match NVIDIA's driver implementation.  
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