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glColorPointerEXT(3G)	       OpenGL Reference		 glColorPointerEXT(3G)

NAME    [Toc]    [Back]

     glColorPointerEXT - define	a array	of colors

C SPECIFICATION    [Toc]    [Back]

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

PARAMETERS    [Toc]    [Back]

     size     Specifies	the number of components per color. It must be 3 or 4.

     type     Specifies	the data type of each color component in the array.
	      Symbolic constants GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT,
	      GL_DOUBLE_EXT, are accepted.

     stride   Specifies	the byte offset	between	consecutive colors.  If	stride
	      is zero the colors are understood	to be tightly packed in	the

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

     pointer  Specifies	a pointer to the first component of the	first color
	      element in the array.

DESCRIPTION    [Toc]    [Back]

     glColorPointerEXT specifies the location and data format of an array of
     color components to use when rendering using the vertex array extension.
     size specifies the	number of components per color,	and must be 3 or 4.
     type specifies the	data type of each color	component and stride gives the
     byte stride from one color	to the next allowing vertices and attributes
     to	be packed into a single	array or stored	in separate arrays.  (Singlearray
 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	color 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 color array is	enabled	and disabled using glEnable and	glDisable with
     the argument GL_COLOR_ARRAY_EXT. If enabled, the color array is used when
     glDrawArraysEXT or	glArrayElementEXT is called.

									Page 1

glColorPointerEXT(3G)	       OpenGL Reference		 glColorPointerEXT(3G)

     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 vertices and vertex

NOTES    [Toc]    [Back]

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

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

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

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

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

     glColorPointerEXT commands	are not	entered	into display lists.

     glColorPointerEXT 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    [Toc]    [Back]

     GL_INVALID_VALUE is generated if size is not 3 or 4.

     GL_INVALID_ENUM is	generated if type is not an accepted value.

     GL_INVALID_VALUE is generated if stride or	count is negative.

ASSOCIATED GETS    [Toc]    [Back]

     glIsEnabled with argument GL_COLOR_ARRAY_EXT
     glGet with	argument GL_COLOR_ARRAY_SIZE_EXT
     glGet with	argument GL_COLOR_ARRAY_TYPE_EXT
     glGet with	argument GL_COLOR_ARRAY_STRIDE_EXT
     glGet with	argument GL_COLOR_ARRAY_COUNT_EXT
     glGetPointervEXT with argument GL_COLOR_ARRAY_POINTER_EXT

									Page 2

glColorPointerEXT(3G)	       OpenGL Reference		 glColorPointerEXT(3G)

     On	RealityEngine, RealityEngine2, and VTX systems,	do not enable or
     between a call to glNewList and the corresponding call to glEndList.
     Instead, enable or	disable	before the call	to glNewList.

     On	InfiniteReality	systems	it is particularly important to	minimize the
     amount of data transferred	from the application to	the graphics pipe,
     since the host-to-pipe bandwidth limit can	cause a	performance
     bottleneck.  One way to reduce the	amount of data transferred per vertex
     is	to use properly-aligned	byte and short data types whenever possible.
     Accordingly, the EXT_vertex_array extension on InfiniteReality systems
     has been optimized	for vertex information packed into the following data
     structures.  (Note: v represents vertex coordinates, c represents color
     components, n represents normal coordinates, and t	represents texture
     coordinates.  Normals must	have unit length.)

	  struct {GLfloat v[3];}
	  struct {GLubyte c[4];	GLfloat	v[3];}
	  struct {GLshort n[3];	GLfloat	v[3];}
	  struct {GLubyte c[4];	GLshort	n[3]; GLfloat v[3];}
	  struct {GLshort t[2];	GLfloat	v[3];}
	  struct {GLshort t[2];	GLubyte	c[4]; GLfloat v[3];}
	  struct {GLshort t[2];	GLshort	n[3]; GLfloat v[3];}
	  struct {GLshort t[2];	GLubyte	c[4]; GLshort n[3]; GLfloat v[3];}
	  struct {GLfloat t[2];	GLfloat	v[3];}
	  struct {GLfloat t[2];	GLubyte	c[4]; GLfloat v[3];}
	  struct {GLfloat t[2];	GLshort	n[3]; GLfloat v[3];}
	  struct {GLfloat t[2];	GLubyte	c[4]; GLshort n[3]; GLfloat v[3];}

     Application-specific fields may be	added to these structures, provided
     that all the fields described above retain	their relative order and word

     An	additional constraint applies when glTexGen is being used.  The
     implementation normally generates all four	texture	coordinates in
     parallel, and must	take special action to generate	just a subset of the
     four coordinates.	Therefore performance is best when none	of the texture
     coordinates are being generated, or when all of them are being generated.
     For example, when using 2D	texturing (generating s	and t coordinates) it
     will be faster to enable texture coordinate generation for	the r and q
     coordinates as well as s and t.  Choose a texture generation mode of
     GL_OBJECT_LINEAR and use the plane	equations (0,0,0,0) and	(0,0,0,1) for
     r and q, respectively.

     Using these structures on InfiniteReality systems can improve performance
     considerably, compared to structures in which all values are singleprecision
 floating	point.

									Page 3

glColorPointerEXT(3G)	       OpenGL Reference		 glColorPointerEXT(3G)

SEE ALSO    [Toc]    [Back]

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

									PPPPaaaaggggeeee 4444
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