GLAPI/glVertexAttribPointer

From OpenGL.org
Jump to: navigation, search
glVertexAttribPointer
Core in version 4.4
Core since version 2.0

glVertexAttribPointer: define an array of generic vertex attribute data. Examples are available.

Function Definition

 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​);
 void glVertexAttribLPointer(GLuint index​, GLint size​, GLenum type​, GLsizei stride​, const GLvoid * pointer​);
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. Additionally, the symbolic constant GL_BGRA​ is accepted by glVertexAttribPointer. The initial value is 4.
type
Specifies the data type of each component in the array. The different functions take different values.
glVertexAttribPointer and glVertexAttribIPointer both take: GL_BYTE​, GL_UNSIGNED_BYTE​, GL_SHORT​, GL_UNSIGNED_SHORT​, GL_INT​, and GL_UNSIGNED_INT​
glVertexAttribPointer also can take: GL_HALF_FLOAT​, GL_FLOAT​, GL_DOUBLE​, GL_FIXED​, GL_INT_2_10_10_10_REV​, GL_UNSIGNED_INT_2_10_10_10_REV​, and GL_UNSIGNED_INT_10F_11F_11F_REV​.
glVertexAttribLPointer takes only GL_DOUBLE​.
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.
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 offset of the first component of the first generic vertex attribute in the array in the data store of the buffer currently bound to the GL_ARRAY_BUFFER​ target. The initial value is 0.

Description

glVertexAttribPointer, glVertexAttribIPointer and glVertexAttribLPointer 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, 4, or GL_BGRA​. 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.

glVertexAttribLPointer specifies state for a generic vertex attribute array associated with a shader attribute variable declared with 64-bit double precision components. type​ must be GL_DOUBLE​. index​, size​, and stride​ behave as described for glVertexAttribPointer and glVertexAttribIPointer.

If pointer​ is not NULL​, a non-zero named buffer object must be bound to the GL_ARRAY_BUFFER​ target (see glBindBuffer), otherwise an error is generated. pointer​ is treated as a byte offset into the buffer object's data store. 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​.

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, glMultiDrawArrays, glDrawElements, glMultiDrawElements, or glDrawRangeElements is called.

Notes

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

GL_UNSIGNED_INT_10F_11F_11F_REV​ is accepted for type​ 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_VALUE​ is generated if size​ is not 1, 2, 3, 4 or (for glVertexAttribPointer), GL_BGRA​.

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 size​ is GL_BGRA​ and type​ is not GL_UNSIGNED_BYTE​, GL_INT_2_10_10_10_REV​ or GL_UNSIGNED_INT_2_10_10_10_REV​.

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 or GL_BGRA​.

GL_INVALID_OPERATION​ is generated if type​ is GL_UNSIGNED_INT_10F_11F_11F_REV​ and size​ is not 3.

GL_INVALID_OPERATION​ is generated by glVertexAttribPointer if size​ is GL_BGRA​ and noramlized​ is GL_FALSE​.

GL_INVALID_OPERATION​ is generated if zero is bound to the GL_ARRAY_BUFFER​ buffer object binding point and the pointer​ argument is not NULL​.

GL_INVALID_OPERATION​ is generated if no vertex array object is bound.

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​

See Also

glBindVertexArray, glBindVertexBuffer, glEnableVertexAttribArray, glVertexAttribFormat, glVertexBindingDivisor, glVertexAttribPointer

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/.