WebGLRenderingContext: vertexAttrib[1234]f[v]() method
The WebGLRenderingContext.vertexAttrib[1234]f[v]()
methods of the WebGL API specify constant
values for generic vertex attributes.
Syntax
js
vertexAttrib1f(index, v0)
vertexAttrib2f(index, v0, v1)
vertexAttrib3f(index, v0, v1, v2)
vertexAttrib4f(index, v0, v1, v2, v3)
vertexAttrib1fv(index, value)
vertexAttrib2fv(index, value)
vertexAttrib3fv(index, value)
vertexAttrib4fv(index, value)
Parameters
index-
A
GLuintspecifying the position of the vertex attribute to be modified. v0, v1, v2, v3-
A floating point
Numberfor the vertex attribute value. value-
A
Float32Arrayfor floating point vector vertex attribute values.
Return value
None (undefined).
Description
While vertex attributes are usually used to specify values which are different for each
vertex (using vertexAttribPointer), it can be useful to specify a constant value. For example, if
you have a shader which has a color vertex attribute, but you want to draw
everything in a single color, you can use vertexAttrib to achieve that
without creating a buffer filled with only one value or having to create a separate
shader which uses a uniform for the color.
This value will be used if a bound array buffer has not been enabled with
enableVertexAttribArray.
Attributes may be matrices, in which case columns of the matrix must be loaded into successive vertex attribute slots.
The values set with vertexAttribPointer are context-global, i.e. they aren't part of the shader state
(like generix vertex attribute indexes to shader variable bindings) and aren't part of
the vertex array object state (like enabled vertex attribute arrays). The only way to
change the values is by calling this function again.
Examples
js
const a_foobar = gl.getAttribLocation(shaderProgram, "foobar");
//either set each component individually:
gl.vertexAttrib3f(a_foobar, 10.0, 5.0, 2.0);
//or provide a Float32Array:
const floatArray = new Float32Array([10.0, 5.0, 2.0]);
gl.vertexAttrib3fv(a_foobar, floatArray);
js
// we want to load the following 3x3 matrix into attribute named "matrix3x3"
// 0 1 2
// 3 4 5
// 6 7 8
const matrix3x3Location = gl.getAttribLocation(shaderProgram, "matrix3x3");
gl.vertexAttrib3f(matrix3x3Location, 0, 3, 6);
gl.vertexAttrib3f(matrix3x3Location + 1, 1, 4, 7);
gl.vertexAttrib3f(matrix3x3Location + 2, 2, 5, 8);
Specifications
| Specification |
|---|
| WebGL Specification # 5.14.10 |
Browser compatibility
BCD tables only load in the browser