2003-2005
3Dlabs Inc. Ltd.
2010-2013
Khronos Group
glVertexAttrib
3G

# glVertexAttrib

Specifies the value of a generic vertex attribute

## C Specification

            void glVertexAttrib1f
            GLuint index
            GLfloat v0

            void glVertexAttrib1s
            GLuint index
            GLshort v0

            void glVertexAttrib1d
            GLuint index
            GLdouble v0

            void glVertexAttribI1i
            GLuint index
            GLint v0

            void glVertexAttribI1ui
            GLuint index
            GLuint v0

            void glVertexAttrib2f
            GLuint index
            GLfloat v0
            GLfloat v1

            void glVertexAttrib2s
            GLuint index
            GLshort v0
            GLshort v1

            void glVertexAttrib2d
            GLuint index
            GLdouble v0
            GLdouble v1

            void glVertexAttribI2i
            GLuint index
            GLint v0
            GLint v1

            void glVertexAttribI2ui
            GLuint index
            GLuint v0
            GLuint v1

            void glVertexAttrib3f
            GLuint index
            GLfloat v0
            GLfloat v1
            GLfloat v2

            void glVertexAttrib3s
            GLuint index
            GLshort v0
            GLshort v1
            GLshort v2

            void glVertexAttrib3d
            GLuint index
            GLdouble v0
            GLdouble v1
            GLdouble v2

            void glVertexAttribI3i
            GLuint index
            GLint v0
            GLint v1
            GLint v2

            void glVertexAttribI3ui
            GLuint index
            GLuint v0
            GLuint v1
            GLuint v2

            void glVertexAttrib4f
            GLuint index
            GLfloat v0
            GLfloat v1
            GLfloat v2
            GLfloat v3

            void glVertexAttrib4s
            GLuint index
            GLshort v0
            GLshort v1
            GLshort v2
            GLshort v3

            void glVertexAttrib4d
            GLuint index
            GLdouble v0
            GLdouble v1
            GLdouble v2
            GLdouble v3

            void glVertexAttrib4Nub
            GLuint index
            GLubyte v0
            GLubyte v1
            GLubyte v2
            GLubyte v3

            void glVertexAttribI4i
            GLuint index
            GLint v0
            GLint v1
            GLint v2
            GLint v3

            void glVertexAttribI4ui
            GLuint index
            GLuint v0
            GLuint v1
            GLuint v2
            GLuint v3

            void glVertexAttribL1d
            GLuint index
            GLdouble v0

            void glVertexAttribL2d
            GLuint index
            GLdouble v0
            GLdouble v1

            void glVertexAttribL3d
            GLuint index
            GLdouble v0
            GLdouble v1
            GLdouble v2

            void glVertexAttribL4d
            GLuint index
            GLdouble v0
            GLdouble v1
            GLdouble v2
            GLdouble v3

            void glVertexAttrib1fv
            GLuint index
            const GLfloat *v

            void glVertexAttrib1sv
            GLuint index
            const GLshort *v

            void glVertexAttrib1dv
            GLuint index
            const GLdouble *v

            void glVertexAttribI1iv
            GLuint index
            const GLint *v

            void glVertexAttribI1uiv
            GLuint index
            const GLuint *v

            void glVertexAttrib2fv
            GLuint index
            const GLfloat *v

            void glVertexAttrib2sv
            GLuint index
            const GLshort *v

            void glVertexAttrib2dv
            GLuint index
            const GLdouble *v

            void glVertexAttribI2iv
            GLuint index
            const GLint *v

            void glVertexAttribI2uiv
            GLuint index
            const GLuint *v

            void glVertexAttrib3fv
            GLuint index
            const GLfloat *v

            void glVertexAttrib3sv
            GLuint index
            const GLshort *v

            void glVertexAttrib3dv
            GLuint index
            const GLdouble *v

            void glVertexAttribI3iv
            GLuint index
            const GLint *v

            void glVertexAttribI3uiv
            GLuint index
            const GLuint *v

            void glVertexAttrib4fv
            GLuint index
            const GLfloat *v

            void glVertexAttrib4sv
            GLuint index
            const GLshort *v

            void glVertexAttrib4dv
            GLuint index
            const GLdouble *v

            void glVertexAttrib4iv
            GLuint index
            const GLint *v

            void glVertexAttrib4bv
            GLuint index
            const GLbyte *v

            void glVertexAttrib4ubv
            GLuint index
            const GLubyte *v

            void glVertexAttrib4usv
            GLuint index
            const GLushort *v

            void glVertexAttrib4uiv
            GLuint index
            const GLuint *v

            void glVertexAttrib4Nbv
            GLuint index
            const GLbyte *v

            void glVertexAttrib4Nsv
            GLuint index
            const GLshort *v

            void glVertexAttrib4Niv
            GLuint index
            const GLint *v

            void glVertexAttrib4Nubv
            GLuint index
            const GLubyte *v

            void glVertexAttrib4Nusv
            GLuint index
            const GLushort *v

            void glVertexAttrib4Nuiv
            GLuint index
            const GLuint *v

            void glVertexAttribI4bv
            GLuint index
            const GLbyte *v

            void glVertexAttribI4ubv
            GLuint index
            const GLubyte *v

            void glVertexAttribI4sv
            GLuint index
            const GLshort *v

            void glVertexAttribI4usv
            GLuint index
            const GLushort *v

            void glVertexAttribI4iv
            GLuint index
            const GLint *v

            void glVertexAttribI4uiv
            GLuint index
            const GLuint *v

            void glVertexAttribL1dv
            GLuint index
            const GLdouble *v

            void glVertexAttribL2dv
            GLuint index
            const GLdouble *v

            void glVertexAttribL3dv
            GLuint index
            const GLdouble *v

            void glVertexAttribL4dv
            GLuint index
            const GLdouble *v

            void glVertexAttribP1ui
            GLuint index
            GLenum type
            GLboolean normalized
            GLuint value

            void glVertexAttribP2ui
            GLuint index
            GLenum type
            GLboolean normalized
            GLuint value

            void glVertexAttribP3ui
            GLuint index
            GLenum type
            GLboolean normalized
            GLuint value

            void glVertexAttribP4ui
            GLuint index
            GLenum type
            GLboolean normalized
            GLuint value

## Parameters

`index`

  Specifies the index of the generic vertex attribute to be modified.

`v0`, `v1`, `v2`, `v3`

  For the scalar commands, specifies the new values to be used for the specified vertex attribute.

`v`

  For the vector commands (`glVertexAttrib*v`), specifies a pointer to an array of values to be used for the generic vertex attribute.

`type`

  For the packed commands (`glVertexAttribP*`), specified the type of packing used on the data. This parameter must be `GL_INT_2_10_10_10_REV` or `GL_UNSIGNED_INT_2_10_10_10_REV`, to specify signed or unsigned data, respectively, or `GL_UNSIGNED_INT_10F_11F_11F_REV` to specify floating point data.

`normalized`

  For the packed commands, if `GL_TRUE`, then the values are to be converted to floating point values by normalizing. Otherwise, they are converted directly to floating-point values. If `type` indicates a floating-pont format, then `normalized` value must be `GL_FALSE`.

`value`

  For the packed commands, specifies the new packed value to be used for the specified vertex attribute.

## Description

The `glVertexAttrib` family of entry points allows an application to pass generic vertex attributes in numbered locations.

Generic attributes are defined as four-component values that are organized into an array. The first entry of this array is numbered 0, and the size of the array is specified by the implementation-dependent constant `GL_MAX_VERTEX_ATTRIBS`. Individual elements of this array can be modified with a `glVertexAttrib` call that specifies the index of the element to be modified and a value for that element.

These commands can be used to specify one, two, three, or all four components of the generic vertex attribute specified by `index`. A `1` in the name of the command indicates that only one value is passed, and it will be used to modify the first component of the generic vertex attribute. The second and third components will be set to 0, and the fourth component will be set to 1. Similarly, a `2` in the name of the command indicates that values are provided for the first two components, the third component will be set to 0, and the fourth component will be set to 1. A `3` in the name of the command indicates that values are provided for the first three components and the fourth component will be set to 1, whereas a `4` in the name indicates that values are provided for all four components.

The letters `s`, `f`, `i`, `d`, `ub`, `us`, and `ui` indicate whether the arguments are of type short, float, int, double, unsigned byte, unsigned short, or unsigned int. When `v` is appended to the name, the commands can take a pointer to an array of such values.

Additional capitalized letters can indicate further alterations to the default behavior of the glVertexAttrib function:

The commands containing `N` indicate that the arguments will be passed as fixed-point values that are scaled to a normalized range according to the component conversion rules defined by the OpenGL specification. Signed values are understood to represent fixed-point values in the range [-1,1], and unsigned values are understood to represent fixed-point values in the range [0,1].

The commands containing `I` indicate that the arguments are extended to full signed or unsigned integers.

The commands containing `P` indicate that the arguments are stored as packed components within a larger natural type.

The commands containing `L` indicate that the arguments are full 64-bit quantities and should be passed directly to shader inputs declared as 64-bit double precision types.

OpenGL Shading Language attribute variables are allowed to be of type mat2, mat3, or mat4. Attributes of these types may be loaded using the `glVertexAttrib` entry points. Matrices must be loaded into successive generic attribute slots in column major order, with one column of the matrix in each generic attribute slot.

A user-defined attribute variable declared in a vertex shader can be bound to a generic attribute index by calling glBindAttribLocation. This allows an application to use more descriptive variable names in a vertex shader. A subsequent change to the specified generic vertex attribute will be immediately reflected as a change to the corresponding attribute variable in the vertex shader.

The binding between a generic vertex attribute index and a user-defined attribute variable in a vertex shader is part of the state of a program object, but the current value of the generic vertex attribute is not. The value of each generic vertex attribute is part of current state, just like standard vertex attributes, and it is maintained even if a different program object is used.

An application may freely modify generic vertex attributes that are not bound to a named vertex shader attribute variable. These values are simply maintained as part of current state and will not be accessed by the vertex shader. If a generic vertex attribute bound to an attribute variable in a vertex shader is not updated while the vertex shader is executing, the vertex shader will repeatedly use the current value for the generic vertex attribute.

## Notes

Generic vertex attributes can be updated at any time.

It is possible for an application to bind more than one attribute name to the same generic vertex attribute index. This is referred to as aliasing, and it is allowed only if just one of the aliased attribute variables is active in the vertex shader, or if no path through the vertex shader consumes more than one of the attributes aliased to the same location. OpenGL implementations are not required to do error checking to detect aliasing, they are allowed to assume that aliasing will not occur, and they are allowed to employ optimizations that work only in the absence of aliasing.

There is no provision for binding standard vertex attributes; therefore, it is not possible to alias generic attributes with standard attributes.

`glVertexAttribL` versions are available only if the GL version is 4.1 or higher.

`GL_UNSIGNED_INT_10F_11F_11F_REV` is accepted for `type` by `glVertexAttribP*` only if the GL version is 4.4 or higher.

## Errors

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

`GL_INVALID_ENUM` is generated if `glVertexAttribP*` is used with a `type` other than `GL_INT_2_10_10_10_REV`, `GL_UNSIGNED_INT_2_10_10_10_REV`, or `GL_UNSIGNED_INT_10F_11F_11F_REV`.

`GL_INVALID_ENUM` is generated if `glVertexAttribL` is used with a `type` other than `GL_DOUBLE`.

## Associated Gets

glGet with the argument `GL_CURRENT_PROGRAM`

glGetActiveAttrib with argument `program` and the index of an active attribute variable

glGetAttribLocation with argument `program` and an attribute variable name

glGetVertexAttrib with arguments `GL_CURRENT_VERTEX_ATTRIB` and `index`

## See Also

glBindAttribLocation, glVertexAttribPointer

## Copyright

Copyright 2003-2005 3Dlabs Inc. Ltd. Copyright 2010-2013 Khronos Group. 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/.