subtex(3G)

NAME
     stxld - load part or all of a texture defined with TX_FASTDEFINE

FORTRAN 77 SPECIFICATION
     subroutine subtexload()
     real

PARAMETERS
     target   is the texture target to which the texture we are loading is
              bound.  Currently this must be TX_TEXTURE_0.

     id       is the id of the texture we are loading.

     s0       is the starting S coordinate of the subtexture to load.

     s1       is the ending S coordinate of the subtexture to load.

     t0       is the starting T coordinate of the subtexture to load.

     t1       is the ending T coordinate of the subtexture to load.

     nt       is number of words in the subtexture array.

     texture  is the long word aligned array of texels to load.

     flags    is a special modifier used for performance-critical, common
              cases such as loading a 64x64 1 component 12bit subtexture with
              one texel per 16bit word.

DESCRIPTION
     stxld loads some or all of a texture that is currently allocated space in
     texture memory.  The transfer uses the pixmode and scale and bias
     settings in effect at the time of the texdef2d if TX_EXTERNAL_FORMAT,
     TX_PIXMODE was specified in the properties.

     The values s0,s1,t0,t1 are mapped to texel values by
     start_s_texel = s0*texture_width;
     start_t_texel = t0*texture_height;
     end_s_texel   = s1*texture_width - 1;
     end_t_texel   = t1*texture_height - 1;

     s0,s1,t0,t1 should fall on texels that are a multiple of 32, i.e. for a
     texture that is 256x128, s0,s1 can be
     0,.125,.25..375,.5,.625,.750,.875,1.0, while t0,t1 can be
     0.,.25,.50.,75.,1.0. Results are undefined for any other values.

     If 1 is passed for flags, the data will be transferred as formatted 16bit
     texels to the graphics system with minimal interpretation, i.e., no scale
     and bias and no pixmode transformations.  A significant gain in transfer
     speed may be achieved for RealityEngine systems.  Only data that is 64
     texels on a side may be sent. A common use of this is to send 64x64 tiles
     of 12 bit intensity data stored in the low bits of a 16bit datum.
     If 2 is passed for flags, 8bit/component ABGR data will be transferred to
     the graphics system with minimal interpretation, i.e., no scale and bias
     and no pixmode transformations.  A significant gain in transfer speed may
     be achieved for RealityEngine systems.  Only data that is 128 texels on a
     side may be sent. A common use of this is to send 128x128 tiles of 32bit
     ABGR data.

SEE ALSO
NOTES
     stxld is supported only on RealityEngine systems with release 5.0.1 or
     greater.