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glNormalPointer
Chapter 12
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glNormalPointer
glNormalPointer: define an array of normals.
C Specification
void glNormalPointer(
GLenum type,
GLsizei stride,
const GLvoid *pointer)
Parameters
type Specifies the data type of each coordinate in the array. Symbolic
constants GL_BYTE, GL_SHORT, GL_INT, GL_FLOAT, and
GL_DOUBLE are accepted. The initial value is GL_FLOAT.
stride Specifies the byte offset between consecutive normals. If stride is 0--
the initial value--the normals are understood to be tightly packed in
the array.
pointer Specifies a pointer to the first coordinate of the first normal in the
array.
Description
glNormalPointer specifies the location and data format of an array of normals to use
when rendering. type specifies the data type of the normal coordinates and stride gives
the byte stride from one normal 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 normal array
is specified, type, stride, and pointer are saved as client-side state.
To enable and disable the normal array, call glEnableClientState and
glDisableClientState with the argument GL_NORMAL_ARRAY. If enabled, the normal
array is used when glDrawArrays, glDrawElements, or glArrayElement is called.
Use glDrawArrays to construct a sequence of primitives (all of the same type) from
pre-specified vertex and vertex attribute arrays. Use glArrayElement to specify
primitives by indexing vertexes and vertex attributes and glDrawElements to construct
a sequence of primitives by indexing vertexes and vertex attributes.
Notes
glNormalPointer is available only if the GL version is 1.1 or greater.
The normal array is initially disabled and isn’t accessed when glArrayElement,
glDrawElements, or glDrawArrays is called.
Execution of glNormalPointer is not allowed between glBegin and the corresponding
glEnd, but an error may or may not be generated. If an error is not generated, the
operation is undefined.
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