GLDRAWARRAYSINSTANCE(3G)					   OpenGL Manual					  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_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 (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/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014						  GLDRAWARRAYSINSTANCE(3G)