GLDRAWELEMENTSINSTAN(3G)					    OpenGL 3.3						  GLDRAWELEMENTSINSTAN(3G)

NAME

       glDrawElementsInstanced - draw multiple instances of a set of elements

C SPECIFICATION

       void glDrawElementsInstanced(GLenum mode, GLsizei count, GLenum type, const void * indices, GLsizei primcount);

PARAMETERS

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

       count
	   Specifies the number of elements to be rendered.

       type
	   Specifies the type of the values in indices. Must be one of GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, or GL_UNSIGNED_INT.

       indices
	   Specifies a pointer to the location where the indices are stored.

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

DESCRIPTION

       glDrawElementsInstanced behaves identically to glDrawElements() except that primcount instances of the set 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.

       glDrawElementsInstanced has the same effect as:

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

NOTES

       glDrawElementsInstanced 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 GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, or
       GL_TRIANGLES.

       GL_INVALID_VALUE is generated if count or primcount are negative.

       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_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

       glDrawElements(), glDrawArraysInstanced()

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						  GLDRAWELEMENTSINSTAN(3G)