bionic (3) ALLEGRO_PRIM_ATTR.3alleg5.gz

NAME

       ALLEGRO_PRIM_ATTR - Allegro 5 API

SYNOPSIS

              #include <allegro5/allegro_primitives.h>

              typedef enum ALLEGRO_PRIM_ATTR

DESCRIPTION

       Enumerates the types of vertex attributes that a custom vertex may have.

       • ALLEGRO_PRIM_POSITION   -   Position   information,   can   be  stored  only  in  ALLEGRO_PRIM_SHORT_2,
         ALLEGRO_PRIM_FLOAT_2 and ALLEGRO_PRIM_FLOAT_3.

       • ALLEGRO_PRIM_COLOR_ATTR - Color information, stored in an ALLEGRO_COLOR(3alleg5).  The storage field of
         ALLEGRO_VERTEX_ELEMENT is ignored

       • ALLEGRO_PRIM_TEX_COORD - Texture coordinate information, can be stored only in ALLEGRO_PRIM_FLOAT_2 and
         ALLEGRO_PRIM_SHORT_2.  These coordinates are normalized by the width and height of the texture, meaning
         that the bottom-right corner has texture coordinates of (1, 1).

       • ALLEGRO_PRIM_TEX_COORD_PIXEL    -   Texture   coordinate   information,   can   be   stored   only   in
         ALLEGRO_PRIM_FLOAT_2 and ALLEGRO_PRIM_SHORT_2.  These coordinates are measured in pixels.

       • ALLEGRO_PRIM_USER_ATTR - A user specified attribute.  You can use any storage for this attribute.   You
         may  have  at most ALLEGRO_PRIM_MAX_USER_ATTR (currently 10) of these that you can specify by adding an
         index   to   the   value   of   ALLEGRO_PRIM_USER_ATTR,   e.g.    the   first   user    attribute    is
         ALLEGRO_PRIM_USER_ATTR + 0, the second is ALLEGRO_PRIM_USER_ATTR + 1 and so on.

         To  access  these  custom  attributes from GLSL shaders you need to declare attributes that follow this
         nomenclature: user_attr_# where # is the index of the attribute.

         To access these custom attributes from HLSL  you  need  to  declare  a  parameter  with  the  following
         semantics:  TEXCOORD{# + 2}  where  #  is the index of the attribute.  E.g.  the first attribute can be
         accessed via TEXCOORD2, second via TEXCOORD3 and so on.

         Since: 5.1.6

SEE ALSO

       ALLEGRO_VERTEX_DECL(3alleg5), ALLEGRO_PRIM_STORAGE(3alleg5)