NAME

glXCreateContext - create a new GLX rendering context

C SPECIFICATION

GLXContext ggllXXCCrreeaatteeCCoonntteexxtt( Display _*_d_p_y,
                             XVisualInfo _*_v_i_s,
                             GLXContext _s_h_a_r_e_L_i_s_t,
                             Bool _d_i_r_e_c_t )

delim $$

PARAMETERS

_d_p_y
Specifies the connection to the X server.
_v_i_s
Specifies the visual that defines the frame buffer resources available to the rendering context. It is a pointer to an XXVViissuuaallIInnffoo structure, not a visual ID or a pointer to a VViissuuaall.
_s_h_a_r_e_L_i_s_t
Specifies the context with which to share display lists. NNUULLLL indicates that no sharing is to take place.
_d_i_r_e_c_t
Specifies whether rendering is to be done with a direct connection to the graphics system if possible (TTrruuee) or through the X server (FFaallssee).

DESCRIPTION

ggllXXCCrreeaatteeCCoonntteexxtt creates a GLX rendering context and returns its handle. This context can be used to render into both windows and GLX pixmaps. If ggllXXCCrreeaatteeCCoonntteexxtt fails to create a rendering context, NNUULLLL is returned.

If _d_i_r_e_c_t is TTrruuee, then a direct rendering context is created if the implementation supports direct rendering, if the connection is to an X server that is local, and if a direct rendering context is available. (An implementation may return an indirect context when _d_i_r_e_c_t is TTrruuee). If _d_i_r_e_c_t is FFaallssee, then a rendering context that renders through the X server is always created. Direct rendering provides a performance advantage in some implementations. However, direct rendering contexts cannot be shared outside a single process, and they may be unable to render to GLX pixmaps.

If _s_h_a_r_e_L_i_s_t is not NNUULLLL, then all display-list indexes and definitions are shared by context _s_h_a_r_e_L_i_s_t and by the newly created context. An arbitrary number of contexts can share a single display-list space. However, all rendering contexts that share a single display-list space must themselves exist in the same address space. Two rendering contexts share an address space if both are nondirect using the same server, or if both are direct and owned by a single process. Note that in the nondirect case, it is not necessary for the calling threads to share an address space, only for their related rendering contexts to share an address space.

If the GL version is 1.1 or greater, then all texture objects except object 0, are shared by any contexts that share display lists.

NOTES

XXVViissuuaallIInnffoo is defined in _X_u_t_i_l_._h_. It is a structure that includes _v_i_s_u_a_l, _v_i_s_u_a_l_I_D, _s_c_r_e_e_n, and _d_e_p_t_h elements.

A _p_r_o_c_e_s_s is a single execution environment, implemented in a single address space, consisting of one or more threads.

A _t_h_r_e_a_d is one of a set of subprocesses that share a single address space, but maintain separate program counters, stack spaces, and other related global data. A _t_h_r_e_a_d that is the only member of its subprocess group is equivalent to a _p_r_o_c_e_s_s.

It may not be possible to render to a GLX pixmap with a direct rendering context.

ERRORS

NNUULLLL is returned if execution fails on the client side.

BBaaddMMaattcchh is generated if the context to be created would not share the address space or the screen of the context specified by _s_h_a_r_e_L_i_s_t.

BBaaddVVaalluuee is generated if _v_i_s is not a valid visual (for example, if a particular GLX implementation does not support it).

GGLLXXBBaaddCCoonntteexxtt is generated if _s_h_a_r_e_L_i_s_t is not a GLX context and is not NNUULLLL.

BBaaddAAlllloocc is generated if the server does not have enough resources to allocate the new context.

SEE ALSO

ggllXXDDeessttrrooyyCCoonntteexxtt, ggllXXGGeettCCoonnffiigg, ggllXXIIssDDiirreecctt, ggllXXMMaakkeeCCuurrrreenntt