fglTexCoordPointer(3G) OpenGL Reference fglTexCoordPointer(3G)NAMEfglTexCoordPointer - define an array of texture coordinates
FORTRAN SPECIFICATION
SUBROUTINE fglTexCoordPointer( INTEGER*4 size,
INTEGER*4 type,
INTEGER*4 stride,
CHARACTER*8 pointer )
PARAMETERS
size Specifies the number of coordinates per array element. Must be
1, 2, 3 or 4. The initial value is 4.
type Specifies the data type of each texture coordinate. Symbolic
constants GL_SHORT, GL_INT, GL_FLOAT, or GL_DOUBLE are accepted.
The initial value is GL_FLOAT.
stride Specifies the byte offset between consecutive array elements.
If stride is 0, the array elements are understood to be tightly
packed. The initial value is 0.
pointer Specifies a pointer to the first coordinate of the first element
in the array. The initial value is 0.
DESCRIPTIONfglTexCoordPointer specifies the location and data format of an array of
texture coordinates to use when rendering. size specifies the number of
coordinates per element, and must be 1, 2, 3, or 4. type specifies the
data type of each texture coordinate and stride specifies the byte stride
from one array element to the next allowing vertices 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
fglInterleavedArrays.) When a texture coordinate array is specified,
size, type, stride, and pointer are saved client-side state.
To enable and disable the texture coordinate array, call
fglEnableClientState and fglDisableClientState with the argument
GL_TEXTURE_COORD_ARRAY. If enabled, the texture coordinate array is used
when fglDrawArrays, fglDrawElements, fglDrawRangeElements or
fglArrayElement is called.
Use fglDrawArrays to construct a sequence of primitives (all of the same
type) from prespecified vertex and vertex attribute arrays. Use
fglArrayElement to specify primitives by indexing vertices and vertex
attributes and fglDrawElements to construct a sequence of primitives by
indexing vertices and vertex attributes.
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fglTexCoordPointer(3G) OpenGL Reference fglTexCoordPointer(3G)NOTESfglTexCoordPointer is available only if the GL version is 1.1 or greater.
The texture coordinate array is initially disabled and it won't be
accessed when fglArrayElement, fglDrawElements, fglDrawRangeElements, or
fglDrawArrays is called.
Execution of fglTexCoordPointer is not allowed between the execution of
fglBegin and the corresponding execution of fglEnd, but an error may or
may not be generated. If no error is generated, the operation is
undefined.
fglTexCoordPointer is typically implemented on the client side with no
protocol.
The texture coordinate array parameters are client-side state and are
therefore not saved or restored by fglPushAttrib and fglPopAttrib. Use
fglPushClientAttrib and fglPopClientAttrib instead.
ERRORS
GL_INVALID_VALUE is generated if size is not 1, 2, 3, or 4.
GL_INVALID_ENUM is generated if type is not an accepted value.
GL_INVALID_VALUE is generated if stride is negative.
ASSOCIATED GETS
fglIsEnabled with argument GL_TEXTURE_COORD_ARRAY
fglGet with argument GL_TEXTURE_COORD_ARRAY_SIZE
fglGet with argument GL_TEXTURE_COORD_ARRAY_TYPE
fglGetPointerv with argument GL_TEXTURE_COORD_ARRAY_POINTER
MACHINE DEPENDENCIES
On RealityEngine, RealityEngine2, and VTX systems, do not enable or
disable GL_VERTEX_ARRAY, GL_VERTEX_ARRAY_EXT, GL_NORMAL_ARRAY,
GL_NORMAL_ARRAY_EXT, GL_COLOR_ARRAY, GL_COLOR_ARRAY_EXT,
GL_INDEX_ARRAY,GL_INDEX_ARRAY_EXT, GL_TEXTURE_COORD_ARRAY,
GL_TEXTURE_COORD_ARRAY_EXT, GL_EDGE_FLAG_ARRAY or GL_EDGE_FLAG_ARRAY_EXT
between a call to fglNewList and the corresponding call to fglEndList.
Instead, enable or disable before the call to fglNewList.
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.)
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fglTexCoordPointer(3G) OpenGL Reference fglTexCoordPointer(3G)
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
alignment.
An additional constraint applies when fglTexGen 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 single-
precision floating point.
SEE ALSO
fglArrayElement, fglColorPointer, fglDrawArrays, fglDrawElements,
fglDrawRangeElements, fglEdgeFlagPointer, fglEnable, fglGetPointerv,
fglIndexPointer, fglNormalPointer, fglPopClientAttrib,
fglPushClientAttrib, fglTexCoord, fglVertexPointer
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