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_TRIANGLESGL_LINES_ADJACENCY, GL_LINE_STRIP_ADJACENCY, GL_TRIANGLES_ADJACENCY,
           GL_TRIANGLE_STRIP_ADJACENCY and GL_PATCHES 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;
               }

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 © 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/.

AUTHORS

       opengl.org