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GLDRAWARRAYSINSTANCE(3G)                         OpenGL 3.3                         GLDRAWARRAYSINSTANCE(3G)



NAME
       glDrawArraysInstanced - draw multiple instances of a range of elements

C SPECIFICATION
       void glDrawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei primcount);

PARAMETERS
       mode
           Specifies what kind of primitives to render. Symbolic constants GL_POINTS, GL_LINE_STRIP,
           GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_TRIANGLES GL_LINES_ADJACENCY,
           GL_LINE_STRIP_ADJACENCY, GL_TRIANGLES_ADJACENCY andGL_TRIANGLE_STRIP_ADJACENCY are accepted.

       first
           Specifies the starting index in the enabled arrays.

       count
           Specifies the number of indices to be rendered.

       primcount
           Specifies the number of instances of the specified range of indices to be rendered.

DESCRIPTION
       glDrawArraysInstanced behaves identically to glDrawArrays() except that primcount instances of the
       range of elements are executed and the value of the internal counter instanceID advances for each
       iteration.  instanceID is an internal 32-bit integer counter that may be read by a vertex shader as
       gl_InstanceID.


       glDrawArraysInstanced has the same effect as:

               if ( mode or count is invalid )
                   generate appropriate error
               else {
                   for (int i = 0; i < primcount ; i++) {
                       instanceID = i;
                       glDrawArrays(mode, first, count);
                   }
                   instanceID = 0;
               }


NOTES
       glDrawArraysInstanced is available only if the GL version is 3.1 or greater.


       GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY and GL_TRIANGLES_ADJACENCY
       are available only if the GL version is 3.2 or greater.

ERRORS
       GL_INVALID_ENUM is generated if mode is not one of the accepted values.


       GL_INVALID_OPERATION is generated if a geometry shader is active and mode is incompatible with the
       input primitive type of the geometry shader in the currently installed program object.


       GL_INVALID_VALUE is generated if count or primcount are negative.


       GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to an enabled array and
       the buffer object's data store is currently mapped.

SEE ALSO
       glDrawArrays(), glDrawElementsInstanced()


COPYRIGHT
       Copyright (C) 2010 Khronos Group. This material may be distributed subject to the terms and
       conditions set forth in the Open Publication License, v 1.0, 8 June 1999.
       http://opencontent.org/openpub/.



OpenGL 3.3                                       03/08/2011                         GLDRAWARRAYSINSTANCE(3G)