glDrawElements(3G)	       OpenGL Reference		    glDrawElements(3G)

NAME    [Toc]    [Back]

     glDrawElements - render primitives	from array data

C SPECIFICATION    [Toc]    [Back]

     void glDrawElements( GLenum mode,
			  GLsizei count,
			  GLenum type,
			  const	GLvoid *indices	)

PARAMETERS    [Toc]    [Back]

     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_QUAD_STRIP,
	      GL_QUADS,	and GL_POLYGON 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.

DESCRIPTION    [Toc]    [Back]

     glDrawElements specifies multiple geometric primitives with very few
     subroutine	calls. Instead of calling a GL function	to pass	each
     individual	vertex,	normal,	texture	coordinate, edge flag, or color, you
     can prespecify separate arrays of vertices, normals, and so on and	use
     them to construct a sequence of primitives	with a single call to
     glDrawElements.

     When glDrawElements is called, it uses count sequential elements from an
     enabled array, starting at	indices	to construct a sequence	of geometric
     primitives. mode specifies	what kind of primitives	are constructed, and
     how the array elements construct these primitives.	If more	than one array
     is	enabled, each is used. If GL_VERTEX_ARRAY is not enabled, no geometric
     primitives	are constructed.

     Vertex attributes that are	modified by glDrawElements have	an unspecified
     value after glDrawElements	returns. For example, if GL_COLOR_ARRAY	is
     enabled, the value	of the current color is	undefined after	glDrawElements
     executes. Attributes that aren't modified maintain	their previous values.

NOTES    [Toc]    [Back]

     glDrawElements is available only if the GL	version	is 1.1 or greater.

     glDrawElements is included	in display lists. If glDrawElements is entered
     into a display list, the necessary	array data (determined by the array
     pointers and enables) is also entered into	the display list. Because the
     array pointers and	enables	are client-side	state, their values affect



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glDrawElements(3G)	       OpenGL Reference		    glDrawElements(3G)



     display lists when	the lists are created, not when	the lists are
     executed.

ERRORS    [Toc]    [Back]

     GL_INVALID_ENUM is	generated if mode is not an accepted value.

     GL_INVALID_VALUE is generated if count is negative.

     GL_INVALID_OPERATION is generated if glDrawElements is executed between
     the execution of glBegin and the corresponding glEnd.

SEE ALSO    [Toc]    [Back]

     glArrayElement, glColorPointer, glDrawArrays, glDrawRangeElements,
     glEdgeFlagPointer,	glGetPointerv, glIndexPointer, glInterleavedArrays,
     glNormalPointer, glTexCoordPointer, glVertexPointer


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