Web/API/WebGL2RenderingContext/vertexAttribIPointer

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The WebGL2RenderingContext.vertexAttribIPointer() method of the WebGL 2 API specifies integer data formats and locations of vertex attributes in a vertex attributes array.

Syntax

void gl.vertexAttribIPointer(index, size, type, stride, offset);

Parameters

index: A GLuint specifying the index of the vertex attribute that is to be modified.
size: A GLint specifying the number of components per vertex attribute. Must be 1, 2, 3, or 4.
type: A GLenum specifying the data type of each component in the array. Must be one of: gl.BYTE, gl.UNSIGNED_BYTE, gl.SHORT, gl.UNSIGNED_SHORT, gl.INT, or gl.UNSIGNED_INT.
stride: A GLsizei specifying the offset in bytes between the beginning of consecutive vertex attributes.
offset: A GLintptr specifying an offset in bytes of the first component in the vertex attribute array. Must be a multiple of type.

Return value

None.

Description

Very similar to WebGLRenderingContext.vertexAttribPointer(). The main difference is that while values specified by vertexAttribPointer are always interpreted as floating-point values in the shader (even if they were originally specified as integers in the buffer), this method allows specifying values which are interpreted as integers in the shader.

Examples

Linear Blend Skinning

//Describe the layout of the buffer:
//1. position
gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 20, 0);
gl.enableVertexAttribArray(0);
//2. bone weights, normalized to [0, 1]
gl.vertexAttribPointer(1, 4, gl.UNSIGNED_BYTE, true, 20, 12);
gl.enableVertexAttribArray(1);
//3. bone indices, interpreted as integer
gl.vertexAttribIPointer(2, 4, gl.UNSIGNED_BYTE, 20, 16);
gl.enableVertexAttribArray(2);

//Connect to attributes from the vertex shader
gl.bindAttribLocation(shaderProgram, 0, "position");
gl.bindAttribLocation(shaderProgram, 1, "boneWeights");
gl.bindAttribLocation(shaderProgram, 2, "boneIndices");

<script id="shader-vs" type="x-shader/x-vertex">#version 300 es

uniform mat4 mvMatrix;
uniform mat4 bones[120];

in vec3 position;
in vec4 boneWeights;
in uvec4 boneIndices;//read as 4-component unsigned integer

void main() {
    vec4 skinnedPosition =
        bones[boneIndices.s] * vec4(position, 1.0) * boneWeights.s +
        bones[boneIndices.t] * vec4(position, 1.0) * boneWeights.t +
        bones[boneIndices.p] * vec4(position, 1.0) * boneWeights.p +
        bones[boneIndices.q] * vec4(position, 1.0) * boneWeights.q;
    gl_Position = mvMatrix * skinnedPosition;
}
</script>

Specifications

Specification	Status	Comment
WebGL 2.0The definition of 'vertexAttribIPointer' in that specification.	Editor's Draft	Initial definition for WebGL.
OpenGL ES 3.0The definition of 'glVertexAttribPointer' in that specification.	Standard	Man page of the (similar) OpenGL API.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`vertexAttribIPointer`	Chrome Full support 56	Edge Full support 79	Firefox Full support 51	IE No support No	Opera Full support 43	Safari No support No	WebView Android Full support 58	Chrome Android Full support 58	Firefox Android Full support 51	Opera Android Full support 43	Safari iOS No support No	Samsung Internet Android Full support 7.0

Legend

Full support: Full support
No support: No support