glColorPointer(3G) OpenGL Reference glColorPointer(3G)
NAME
glColorPointer - define an array of colors
C SPECIFICATION
void glColorPointer( GLint size,
GLenum type,
GLsizei stride,
const GLvoid *pointer )
PARAMETERS
size Specifies the number of components per color. Must be 3 or 4.
type Specifies the data type of each color component in the array.
Symbolic constants GLBYTE, GLUNSIGNEDBYTE, GLSHORT,
GLUNSIGNEDSHORT, GLINT, GLUNSIGNEDINT, GLFLOAT, and
GLDOUBLE are accepted.
stride Specifies the byte offset between consecutive colors. If stride
is 0, (the initial value), the colors are understood to be
tightly packed in the array.
pointer Specifies a pointer to the first component of the first color
element in the array.
DESCRIPTION
glColorPointer specifies the location and data format of an array of
color components to use when rendering. 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 specifies the byte stride from one
color 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; see glInterleavedArrays.)
When a color array is specified, size, type, stride, and pointer are
saved as client-side state.
To enable and disable the color array, call glEnableClientState and
glDisableClientState with the argument GLCOLORARRAY. If enabled, the
color array is used when glDrawArrays, glDrawElements, or glArrayElement
is called.
NOTES
glColorPointer is available only if the GL version is 1.1 or greater.
The color array is initially disabled and isn't accessed when
glArrayElement, glDrawArrays, or glDrawElements is called.
Execution of glColorPointer is not allowed between the execution of
glBegin and the corresponding execution of glEnd, but an error may or may
not be generated. If no error is generated, the operation is undefined.
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glColorPointer(3G) OpenGL Reference glColorPointer(3G)
glColorPointer is typically implemented on the client side.
Color array parameters are client-side state and are therefore not saved
or restored by glPushAttrib and glPopAttrib. Use glPushClientAttrib and
glPopClientAttrib instead.
ERRORS
GLINVALIDVALUE is generated if size is not 3 or 4.
GLINVALIDENUM is generated if type is not an accepted value.
GLINVALIDVALUE is generated if stride is negative.
ASSOCIATED GETS
glIsEnabled with argument GLCOLORARRAY
glGet with argument GLCOLORARRAYSIZE
glGet with argument GLCOLORARRAYTYPE
glGet with argument GLCOLORARRAYSTRIDE
glGetPointerv with argument GLCOLORARRAYPOINTER
MACHINE DEPENDENCIES
On RealityEngine, RealityEngine2, and VTX systems, do not enable or
disable GLVERTEXARRAY, GLVERTEXARRAYEXT, GLNORMALARRAY,
GLNORMALARRAYEXT, GLCOLORARRAY, GLCOLORARRAYEXT,
GLINDEXARRAY,GLINDEXARRAYEXT, GLTEXTURECOORDARRAY,
GLTEXTURECOORDARRAYEXT, GLEDGEFLAGARRAY or GLEDGEFLAGARRAYEXT
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 EXTvertexarray 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];}
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glColorPointer(3G) OpenGL Reference glColorPointer(3G)
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
alignment.
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
GLOBJECTLINEAR 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 single-
precision floating point.
SEE ALSO
glArrayElement, glDrawArrays, glDrawElements, glEdgeFlagPointer,
glEnable, glGetPointerv, glIndexPointer, glInterleavedArrays,
glNormalPointer, glPopClientAttrib, glPushClientAttrib,
glTexCoordPointer, glVertexPointer
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