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WebGL2RenderingContext.vertexAttribIPointer()

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

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.

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

Browser compatibility

FeatureChromeFirefoxEdgeInternet ExplorerOperaSafari
Basic Support5651.0(No)(No)43(No)
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support(No)(No)(No)(No)(No)(No)(No)

See also

Document Tags and Contributors

 Contributors to this page: fscholz, Jedipedia, teoli
 Last updated by: fscholz,