glVertexPointerEXT.3gl




Name

  glVertexPointerEXT - define an array of vertex data


C Specification

  void glVertexPointerEXT( GLint size,
			   GLenum type,
			   GLsizei stride,
			   GLsizei count,
			   const GLvoid	*pointer )


Parameters


  size	   Specifies the number	of coordinates per vertex, must	be 2,3,	or 4.

  type	   Specifies the data type of each coordinate in the array.  Symbolic
	   constants GL_SHORT, GL_INT, GL_FLOAT, or GL_DOUBLE_EXT are
	   accepted.

  stride   Specifies the byte offset between consecutive vertexes. If stride
	   is 0	the vertexes are understood to be tightly packed in the
	   array.

  count	   Specifies the number	of vertexes, counting from the first, that
	   are static.

  pointer  Specifies a pointer to the first coordinate of the first vertex in
	   the array.

Description

  glVertexPointerEXT specifies the location and data format of an array of
  vertex coordinates to use when rendering using the vertex array extension.
  size specifies the number of coordinates per vertex and type the 
  data type of the coordinates. stride gives the byte stride from one vertex 
  to the next allowing vertexes and attributes to be packed into a single 
  array or stored in separate arrays. (Single-array storage may be more 
  efficient on some implementations.) count indicates the number of array 
  elements (counting from the first) that are static. Static elements may be 
  modified by the application, but once they are modified, the application 
  must explicitly respecify the array before using it for any rendering. When 
  a vertex array is specified, size, type, stride, count, and pointer are saved 
  as client-side state, and static array elements may be cached by the 
  implementation.

  The vertex array is enabled and disabled using glEnable and glDisable	with
  the argument GL_VERTEX_ARRAY_EXT. If enabled,	the vertex array is used when
  glDrawArraysEXT or glArrayElementEXT is called.

  Use glDrawArraysEXT to define	a sequence of primitives (all of the same
  type)	from pre-specified vertex and vertex attribute arrays.	Use
  glArrayElementEXT to specify primitives by indexing vertexes and vertex
  attributes.

Notes

  Non-static array elements are	not accessed until glArrayElementEXT or
  glDrawArraysEXT is executed.

  By default the vertex	array is disabled and it won't be accessed when
  glArrayElementEXT or glDrawArraysEXT is called.


  Although it is not an error to call glVertexPointerEXT between the
  execution of glBegin and the corresponding execution of glEnd, the results
  are undefined.


  glVertexPointerEXT will typically be implemented on the client side with no
  protocol.


  Since	the vertex array parameters are	client side state, they	are not	saved
  or restored by glPushAttrib and glPopAttrib.


  glVertexPointerEXT commands are not entered into display lists.


  glVertexPointerEXT is	part of	the EXT_vertex_array extension, not
  part of the core GL command set. If "GL_EXT_vertex_array" is
  included in the string returned by glGetString, when called with argument
  GL_EXTENSIONS, extension EXT_vertex_array is supported.


Errors

  GL_INVALID_VALUE is generated	if size	is not 2, 3, or	4.

  GL_INVALID_ENUM is generated if type is is not an accepted value.

  GL_INVALID_VALUE is generated	if stride or count is negative.

Associated Gets

  glIsEnabled with argument GL_VERTEX_ARRAY_EXT
  glGet	with argument GL_VERTEX_ARRAY_SIZE_EXT
  glGet	with argument GL_VERTEX_ARRAY_TYPE_EXT
  glGet	with argument GL_VERTEX_ARRAY_STRIDE_EXT
  glGet	with argument GL_VERTEX_ARRAY_COUNT_EXT
  glGetPointervEXT with	argument GL_VERTEX_ARRAY_POINTER_EXT

See Also

  glArrayElementEXT, glColorPointerEXT,	glDrawArraysEXT,
  glEdgeFlagPointerEXT,	glGetPointervEXT, glIndexPointerEXT,
  glNormalPointerEXT, glTexCoordPointerEXT, glEnable



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Last Edited: Fri Feb 24, 1995

AFV