glVertexPointer
[New
- Windows 95, OEM Service Release 2]
The glVertexPointer
function defines an array of vertex data.
void glVertexPointer(
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GLint size, |
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GLenum type, |
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GLsizei stride, |
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GLsizei count, |
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const GLvoid *pointer |
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); |
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Parameters
size
The number of
coordinates per vertex. The value of size must be 2, 3, or 4.
type
The data type
of each coordinate in the array using the following symbolic constants:
GL_SHORT, GL_INT, GL_FLOAT, and GL_DOUBLE.
stride
The byte
offset between consecutive vertices. When stride is zero, the vertices
are tightly packed in the array.
count
The number of
vertices, counting from the first, that are static.
pointer
A pointer to
the first coordinate of the first vertex in the array.
Remarks
The
glVertexPointer function specifies the location and data of an array of
vertex coordinates to use when rendering. The size parameter specifies
the number of coordinates per vertex. The type parameter specifies the
data type of each vertex coordinate. The stride parameter determines the
byte offset from one vertex to the next, enabling the packing of vertices and
attributes in a single array or storage in separate arrays. In some
implementations, storing the vertices and attributes in a single array can be
more efficient than using separate arrays. Starting from the first vertex
element, the count parameter indicates the total number of static
elements. Your application can modify static elements, but once the elements
are modified, the application must explicitly specify the array again before using
the array for any rendering. Non-static array elements are not accessed until
you call glDrawArrays
or glArrayElement.
A vertex
array is enabled when you specify the GL_VERTEX_ARRAY constant with glEnableClientState. When enabled, glDrawArrays
and glArrayElement use the vertex array. By default, the vertex array is
disabled.
You cannot
include glVertexPointer in display lists.
When you
specify a vertex array using glVertexPointer, the values of all the function s
vertex array parameters are saved in a client-side state and static array
elements can be cached. Because the vertex array parameters are client-side
state, their values are not saved or restored by glPushAttrib and glPopAttrib.
Although no
error is generated if you call glVertexPointer within glBegin and glEnd pairs, the results are
undefined.
The following
functions retrieve information related to glVertexPointer:
glGet
with argument GL_VERTEX_ARRAY_SIZE
glGet with
argument GL_VERTEX_ARRAY_STRIDE
glGet with
argument GL_VERTEX_ARRAY_COUNT
glGet with
argument GL_VERTEX_ARRAY_TYPE
glGetPointerv
with argument GL_VERTEX_ARRAY_POINTER
glIsEnabled with argument GL_VERTEX_ARRAY
Error Codes
The following
are the error codes generated and their conditions.
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Error
Code |
Condition |
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GL_INVALID_VALUE
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size was not 2, 3, or 4. |
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GL_INVALID_ENUM
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type was not an accepted value. |
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GL_INVALID_VALUE
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stride or count was negative. |
See Also