The OpenGL Graphics System: A Specification

2.7. VERTEX SPECIFICATION 20
Pointer, IndexPointer, NormalPointer, TexCoordPointer, SecondaryColor-
Pointer, VertexPointer, VertexAttribPointer, ClientActiveTexture, InterleavedArrays,
and PixelStore is not allowed within any Begin/End pair, but an
error may or may not be generated if such execution occurs. If an error is not generated,
GL operation is undefined. (These commands are described in sections 2.8,
3.6.1, and chapter 6.)
2.7 Vertex Specification
Vertices are specified by giving their coordinates in two, three, or four dimensions.
This is done using one of several versions of the Vertex command:
void Vertex{234}{sifd}( T coords );
void Vertex{234}{sifd}v( T coords );
A call to any Vertex command specifies four coordinates: x, y, z, and w. The
x coordinate is the first coordinate, y is second, z is third, and w is fourth. A
call to Vertex2 sets the x and y coordinates; the z coordinate is implicitly set to
zero and the w coordinate to one. Vertex3 sets x, y, and z to the provided values
and w to one. Vertex4 sets all four coordinates, allowing the specification of an
arbitrary point in projective three-space. Invoking a Vertex command outside of a
Begin/End pair results in undefined behavior.
Current values are used in associating auxiliary data with a vertex as described
in section 2.6. A current value may be changed at any time by issuing an appropriate
command. The commands
void TexCoord{1234}{sifd}( T coords );
void TexCoord{1234}{sifd}v( T coords );
specify the current homogeneous texture coordinates, named s, t, r, and q. The
TexCoord1 family of commands set the s coordinate to the provided single argument
while setting t and r to 0 and q to 1. Similarly, TexCoord2 sets s and t to the
specified values, r to 0 and q to 1; TexCoord3 sets s, t, and r, with q set to 1, and
TexCoord4 sets all four texture coordinates.
Implementations must support at least two sets of texture coordinates. The
commands
void MultiTexCoord{1234}{sifd}(enum texture,T coords)
void MultiTexCoord{1234}{sifd}v(enum texture,T
coords)
Version 2.0 - October 22, 2004