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# docs.GL

OpenGL 4
OpenGL 3
OpenGL 2
OpenGL ES 3
OpenGL ES 2

# glVertexAttribPointer

## Name

glVertexAttribPointer — define an array of generic vertex attribute data

## C Specification

`void glVertexAttribPointer(` | GLuint index,
| GLint size,
| GLenum type,
| GLboolean normalized,
| GLsizei stride,
| const GLvoid * pointer`)`;

`void glVertexAttribIPointer(` | GLuint index,
| GLint size,
| GLenum type,
| GLsizei stride,
| const GLvoid * pointer`)`;

## Parameters

`index`

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

`size`

  Specifies the number of components per generic vertex attribute. Must be 1, 2, 3, 4. The initial value is 4.

`type`

  Specifies the data type of each component in the array. The symbolic constants `GL_BYTE`, `GL_UNSIGNED_BYTE`, `GL_SHORT`, `GL_UNSIGNED_SHORT`, `GL_INT`, and `GL_UNSIGNED_INT` are accepted by both functions. Additionally `GL_HALF_FLOAT`, `GL_FLOAT`, `GL_FIXED`, `GL_INT_2_10_10_10_REV`, and `GL_UNSIGNED_INT_2_10_10_10_REV` are accepted by `glVertexAttribPointer`. The initial value is `GL_FLOAT`.

`normalized`

  For `glVertexAttribPointer`, specifies whether fixed-point data values should be normalized (`GL_TRUE`) or converted directly as fixed-point values (`GL_FALSE`) when they are accessed. This parameter is ignored if `type` is `GL_FIXED`.

`stride`

  Specifies the byte offset between consecutive generic vertex attributes. If `stride` is 0, the generic vertex attributes are understood to be tightly packed in the array. The initial value is 0.

`pointer`

  Specifies a pointer to the first generic vertex attribute in the array. If a non-zero buffer is currently bound to the `GL_ARRAY_BUFFER` target, `pointer` specifies an offset of into the array in the data store of that buffer. The initial value is 0.

## Description

`glVertexAttribPointer` and `glVertexAttribIPointer` specify the location and data format of the array of generic vertex attributes at index `index` to use when rendering. `size` specifies the number of components per attribute and must be 1, 2, 3 or 4. `type` specifies the data type of each component, and `stride` specifies the byte stride from one attribute to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays.

For `glVertexAttribPointer`, if `normalized` is set to `GL_TRUE`, it indicates that values stored in an integer format are to be mapped to the range [-1,1] (for signed values) or [0,1] (for unsigned values) when they are accessed and converted to floating point. Otherwise, values will be converted to floats directly without normalization.

For `glVertexAttribIPointer`, only the integer types `GL_BYTE`, `GL_UNSIGNED_BYTE`, `GL_SHORT`, `GL_UNSIGNED_SHORT`, `GL_INT`, `GL_UNSIGNED_INT` are accepted. Values are always left as integer values.

If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER` target (see glBindBuffer), `pointer` is treated as a byte offset into the buffer object's data store and the buffer object binding (`GL_ARRAY_BUFFER_BINDING`) is saved as generic vertex attribute array state (`GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING`) for index `index`.

Client vertex arrays (a binding of zero to the `GL_ARRAY_BUFFER` target) are only valid in conjunction with the zero named vertex array object. This is provided for backwards compatibility with OpenGL ES 2.0.

When a generic vertex attribute array is specified, `size`, `type`, `normalized`, `stride`, and `pointer` are saved as vertex array state, in addition to the current vertex array buffer object binding.

To enable and disable a generic vertex attribute array, call glEnableVertexAttribArray and glDisableVertexAttribArray with `index`. If enabled, the generic vertex attribute array is used when glDrawArrays, glDrawArraysInstanced, glDrawElements, glDrawElementsIntanced, or glDrawRangeElements is called.

## Notes

Each generic vertex attribute array is initially disabled and isn't accessed when glDrawElements, glDrawRangeElements, glDrawArrays, glDrawArraysInstanced, or glDrawElementsInstanced is called.

## Errors

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

`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.

`GL_INVALID_OPERATION` is generated if `type` is `GL_INT_2_10_10_10_REV` or `GL_UNSIGNED_INT_2_10_10_10_REV` and `size` is not 4.

`GL_INVALID_OPERATION` is generated a non-zero vertex array object is bound, zero is bound to the `GL_ARRAY_BUFFER` buffer object binding point and the `pointer` argument is not `NULL`.

## Associated Gets

glGet with argument `GL_MAX_VERTEX_ATTRIBS`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_ENABLED`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_SIZE`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_TYPE`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_NORMALIZED`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_STRIDE`

glGetVertexAttrib with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING`

glGet with argument `GL_ARRAY_BUFFER_BINDING`

glGetVertexAttribPointerv with arguments `index` and `GL_VERTEX_ATTRIB_ARRAY_POINTER`

## Examples

Render an indexed vertex array (not loaded into OpenGL) using texture UV and normal vertex attributes.

    glEnableVertexAttribArray(texcoord_attrib_index); // Attribute indexes were received from calls to glGetAttribLocation, or passed into glBindAttribLocation.
    glEnableVertexAttribArray(normal_attrib_index);
    glEnableVertexAttribArray(position_attrib_index);

    glVertexAttribPointer(texcoord_attrib_index, 2, GL_FLOAT, false, 0, texcoords_data); // texcoords_data is a float*, 2 per vertex, representing UV coordinates.
    glVertexAttribPointer(normal_attrib_index, 3, GL_FLOAT, false, 0, normals_data); // normals_data is a float*, 3 per vertex, representing normal vectors.
    glVertexAttribPointer(position_attrib_index, 3, GL_FLOAT, false, 0, vertex_data); // vertex_data is a float*, 3 per vertex, representing the position of each vertex

    // num_vertices is the number of verts in your vertex_data.
    // index_data is an array of unsigned int offsets into vertex_data.
    glDrawElements(GL_TRIANGLES, num_vertices, GL_UNSIGNED_INT, index_data);

    glDisableVertexAttribArray(position_attrib_index);
    glDisableVertexAttribArray(texcoord_attrib_index);
    glDisableVertexAttribArray(normal_attrib_index);

Render an indexed buffer object using texture UV and normal vertex attributes.

    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); // vertex_buffer is retrieved from glGenBuffers
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer); // index_buffer is retrieved from glGenBuffers

    glEnableVertexAttribArray(texcoord_attrib_index); // Attribute indexes were received from calls to glGetAttribLocation, or passed into glBindAttribLocation.
    glEnableVertexAttribArray(normal_attrib_index);
    glEnableVertexAttribArray(position_attrib_index);

    // vertex_stride is the size of bytes of each vertex in the buffer object
    // vertex_position_offset and kin are the offset in bytes of the position data
    // in each vertex. For example if your vertex structure is
    // [ position, texcoord, normal ] then position vertex_position_offset will
    // have offset 0, vertex_texcoord_offset is 12 (position is 3 * sizeof(float)
    // bytes large, and texcoord comes just after) and vertex_normal_offset is
    // 20 = 5 * sizeof(float).
    GLintptr vertex_texcoord_offset = 3 * sizeof(float);
    GLintptr vertex_normal_offset = 5 * sizeof(float);
    GLintptr vertex_position_offset = 0 * sizeof(float);

    glVertexAttribPointer(texcoord_attrib_index, 2, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_texcoord_offset);
    glVertexAttribPointer(normal_attrib_index, 3, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_normal_offset);
    glVertexAttribPointer(position_attrib_index, 3, GL_FLOAT, false, vertex_stride, (GLvoid*)vertex_position_offset);

    // num_vertices is the number of verts in your vertex_data.
    // index_data is an array of unsigned int offsets into vertex_data.
    glDrawElements(GL_TRIANGLES, num_vertices, GL_UNSIGNED_INT, NULL);

    glDisableVertexAttribArray(position_attrib_index);
    glDisableVertexAttribArray(texcoord_attrib_index);
    glDisableVertexAttribArray(normal_attrib_index);

## Tutorials

nehe.gamedev.net - iOS Lesson 02 - First Triangle
open.gl - Geometry Shaders
open.gl - Textures Objects and Parameters
open.gl - The Graphics Pipeline
open.gl - Transform Feedback
opengl-tutorial.org - Particles / Instancing
opengl-tutorial.org - Tutorial 13 : Normal Mapping
opengl-tutorial.org - Tutorial 2 : The first triangle
opengl-tutorial.org - Tutorial 4 : A Colored Cube
opengl-tutorial.org - Tutorial 8 : Basic shading

## API Version Support

| OpenGL ES API Version
--- | ---
Function Name | 2.0 | 3.0 | 3.1
`glVertexAttribPointer` | ✔ | ✔ | ✔
`glVertexAttribIPointer` | - | ✔ | ✔

## See Also

glBindAttribLocation, glBindBuffer, glDisableVertexAttribArray, glDrawArrays, glDrawElements, glDrawRangeElements, glEnableVertexAttribArray, glDrawArraysInstanced, glDrawElementsIntanced, glVertexAttrib

## Copyright

Copyright © 2003-2005 3Dlabs Inc. Ltd. Copyright © 2010-2014 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. https://opencontent.org/openpub/.

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