glGetVertexAttrib

Name

glGetVertexAttrib — Return a generic vertex attribute parameter

C Specification

`void glGetVertexAttribdv(`	GLuint	`index`,
	GLenum	`pname`,
	GLdouble *	`params)`;

`void glGetVertexAttribfv(`	GLuint	`index`,
	GLenum	`pname`,
	GLfloat *	`params)`;

`void glGetVertexAttribiv(`	GLuint	`index`,
	GLenum	`pname`,
	GLint *	`params)`;

Parameters

index: Specifies the generic vertex attribute parameter to be queried.
pname: Specifies the symbolic name of the vertex attribute parameter to be queried. Accepted values are GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING, GL_VERTEX_ATTRIB_ARRAY_ENABLED, GL_VERTEX_ATTRIB_ARRAY_SIZE, GL_VERTEX_ATTRIB_ARRAY_STRIDE, GL_VERTEX_ATTRIB_ARRAY_TYPE, GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, or GL_CURRENT_VERTEX_ATTRIB.
params: Returns the requested data.

Description

glGetVertexAttrib returns in params the value of a generic vertex attribute parameter. The generic vertex attribute to be queried is specified by index, and the parameter to be queried is specified by pname.

The accepted parameter names are as follows:

GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING: params returns a single value, the name of the buffer object currently bound to the binding point corresponding to generic vertex attribute array index. If no buffer object is bound, 0 is returned. The initial value is 0.
GL_VERTEX_ATTRIB_ARRAY_ENABLED: params returns a single value that is non-zero (true) if the vertex attribute array for index is enabled and 0 (false) if it is disabled. The initial value is GL_FALSE.
GL_VERTEX_ATTRIB_ARRAY_SIZE: params returns a single value, the size of the vertex attribute array for index. The size is the number of values for each element of the vertex attribute array, and it will be 1, 2, 3, or 4. The initial value is 4.
GL_VERTEX_ATTRIB_ARRAY_STRIDE: params returns a single value, the array stride for (number of bytes between successive elements in) the vertex attribute array for index. A value of 0 indicates that the array elements are stored sequentially in memory. The initial value is 0.
GL_VERTEX_ATTRIB_ARRAY_TYPE: params returns a single value, a symbolic constant indicating the array type for the vertex attribute array for index. Possible values are GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT, and GL_DOUBLE. The initial value is GL_FLOAT.
GL_VERTEX_ATTRIB_ARRAY_NORMALIZED: params returns a single value that is non-zero (true) if fixed-point data types for the vertex attribute array indicated by index are normalized when they are converted to floating point, and 0 (false) otherwise. The initial value is GL_FALSE.
GL_CURRENT_VERTEX_ATTRIB: params returns four values that represent the current value for the generic vertex attribute specified by index. Generic vertex attribute 0 is unique in that it has no current state, so an error will be generated if index is 0. The initial value for all other generic vertex attributes is (0,0,0,1).

All of the parameters except GL_CURRENT_VERTEX_ATTRIB represent client-side state.

Notes

glGetVertexAttrib is available only if the GL version is 2.0 or greater.

If an error is generated, no change is made to the contents of params.

Errors

GL_INVALID_VALUE is generated if index is greater than or equal to GL_MAX_VERTEX_ATTRIBS.

GL_INVALID_ENUM is generated if pname is not an accepted value.

GL_INVALID_OPERATION is generated if index is 0 and pname is GL_CURRENT_VERTEX_ATTRIB.

Associated Gets

glGet with argument GL_MAX_VERTEX_ATTRIBS

glGetVertexAttribPointerv with arguments index and GL_VERTEX_ATTRIB_ARRAY_POINTER

Copyright

Copyright © 2003-2005 3Dlabs Inc. Ltd. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.