Light | Dark

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);

API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glVertexAttribPointer
glVertexAttribIPointer -
Think you can improve this page? Edit this page on GitHub.