material

Note: This documentation is for the old 0.7.0 version of A-Frame. Check out the documentation for the current 1.6.0 version

The material component gives appearance to an entity. We can define properties such as color, opacity, or texture. This is often paired with the geometry component which provides shape.

We can register custom materials to extend the material component to provide a wide range of visual effects.

Example

Defining a red material using the default standard material:

<a-entity geometry="primitive: box" material="color: red"></a-entity>

Here is an example of using a different material:

<a-entity geometry="primitive: box" material="shader: flat; color: red"></a-entity>

Here is an example of using an example custom material:

<a-entity geometry="primitive: plane"
          material="shader: ocean; color: blue; wave-height: 10"></a-entity>

Properties

The material component has some base properties. More properties are available depending on the material type applied.

Events

Built-in Materials

A-Frame ships with a couple of built-in materials.

standard

The standard material is the default material. It uses the physically-based THREE.MeshStandardMaterial.

Properties

These properties are available on top of the base material properties.

Physically-Based Shading

Physically-based shading is a shading model that aims to make materials behave realistically to lighting conditions. Appearance is a result of the interaction between the incoming light and the properties of the material.

To achieve realism, the diffuse color, metalness, roughness properties of the material must be accurately controlled, often based on real-world material studies. Some people have compiled charts of realistic values for different kinds of materials that we can use as a starting point.

For example, for a tree bark material, as an estimation, we might set:

<a-entity geometry="primitive: cylinder"
          material="src: treebark.png; color: #696969; roughness: 1; metalness: 0">
</a-entity>

Distortion Maps

There are three properties which give the illusion of complex geometry:

• Ambient occlusion maps - Applies subtle shadows in areas that receive less ambient light. Direct (point, directional) lights do not affect ambient occlusion maps. Baked ambient occlusion requires a 2nd set of UVs, which may be added to the mesh in modeling software or using JavaScript.
• Displacement maps - Distorts a simpler model at a high resolution allowing more detail. This will affect the mesh’s silhouette but can be expensive.
• Normal maps - Defines the angle of the surface at that point. Giving the appearance of complex geometry without distorting the model. This does not change the geometry but normal maps are cheaper.

Environment Maps

The envMap and sphericalEnvMap properties define what environment the material reflects. The clarity of the environment reflection depends on the metalness, and roughness properties.

The sphericalEnvMap property takes a single spherical mapped texture. Of the kind you would assign to a <a-sky>.

Unlike textures, the envMap property takes a cubemap, six images put together to form a cube. The cubemap wraps around the mesh and applied as a texture.

For example:

<a-scene>
  <a-assets>
    <a-cubemap id="sky">
      <img src="right.png">
      <img src="left.png">
      <img src="top.png">
      <img src="bottom.png">
      <img src="front.png">
      <img src="back.png">
    </a-cubemap>
  </a-assets>

  <a-entity geometry="primitive: box" material="envMap: #sky; roughness: 0"></a-entity>
</a-scene>

flat

The flat material uses the THREE.MeshBasicMaterial. Flat materials are not affected by the scene’s lighting conditions. This is useful for things such as images or videos. Set shader to flat:

<a-entity geometry="primitive: plane" material="shader: flat; src: #cat-image"></a-entity>

Properties

Textures

To set a texture using one of the built-in materials, specify the src property. src can be a selector to either an <img> or <video> element in the asset management system:

<a-scene>
  <a-assets>
    <img id="my-texture" src="texture.png">
  </a-assets>

  <a-entity geometry="primitive: box" material="src: #my-texture"></a-entity>
</a-scene>

src can also be an inline URL. Note that we do not get browser caching or preloading through this method.

<a-scene>
  <a-entity geometry="primitive: box" material="src: url(texture.png)"></a-entity>
</a-scene>

Most of the other properties works together with textures. For example, the color property will act as the base color and multiplies per pixel with the texture. Set it to #fff to maintain the original colors of the texture.

A-Frame caches textures are to not push redundant textures to the GPU.

Video Textures

Whether the video texture loops or autoplays depends on the video element used to create the texture. If we simply pass a URL instead of creating and passing a video element, then the texture will loop and autoplay by default. To specify otherwise, create a video element in the asset management system, and pass a selector for the id attribute (e.g., #my-video):

<a-scene>
  <a-assets>
    <!-- No loop. -->
    <video id="my-video" src="video.mp4" autoplay="true">
  </a-assets>

  <a-entity geometry="primitive: box" material="src: #my-video"></a-entity>
</a-scene>

Controlling Video Textures

To control the video playback such as pausing or seeking, we can use the video element to control media playback. For example:

var videoEl = document.querySelector('#my-video');
videoEl.currentTime = 122;  // Seek to 122 seconds.
videoEl.pause();

This doesn’t work as well if you are passing an inline URL, in which case A-Frame creates a video element internally. To get a handle on the video element, we should define one in <a-assets>.

Canvas Textures

We can use a <canvas> as a texture source. The texture will automatically refresh itself as the canvas changes.

<script>
  AFRAME.registerComponent('draw-canvas', {
    schema: {default: ''},

    init: function () {
      this.canvas = document.getElementById(this.data);
      this.ctx = this.canvas.getContext('2d');

      // Draw on canvas...
    }
  });
</script>

<a-assets>
  <canvas id="my-canvas" crossorigin="anonymous"></canvas>
</a-assets>

<a-entity geometry="primitive: plane" material="src: #my-canvas"
          draw-canvas="my-canvas"></a-entity>

Repeating Textures

We might want to tile textures rather than having them stretch. The repeat property can repeat textures.

<a-entity geometry="primitive: plane; width: 100"
          material="src: carpet.png; repeat: 100 20"></a-entity>

Transparency Issues

Transparency and alpha channels are tricky in 3D graphics. If you are having issues where transparent materials in the foreground do not composite correctly over materials in the background, the issues are probably due to underlying design of the OpenGL compositor (which WebGL is an API for).

In an ideal scenario, transparency in A-Frame would “just work”, regardless of where the developer places an entity in 3D space, or in which order they define the elements in markup. We can often run into scenarios where foreground entities occlude background entities. This creates confusion and unwanted visual defects.

To work around this issue, try changing the order of the entities in the HTML.

Register a Custom Material

We can register custom materials for appearances and effects using AFRAME.registerShader. However, the registerShader API is not yet fully featured and fairly limiting (e.g., no tick handler, some missing uniform types). For most cases for now, we recommend creating a custom material by creating three.js materials (e.g., RawShaderMaterial, ShaderMaterial) in a component:

AFRAME.registerComponent('custom-material', {
  schema: {
    // Add properties.
  },

  init: function () {
    this.material = this.el.getOrCreateObject3D('mesh').material = new THREE.ShaderMaterial({
      // ...
    });
  },

  update: function () {
    // Update `this.material`.
  }
});

registerShader

Like components, custom materials have schema and lifecycle handlers.

Schema

We can define material properties just as we would with component properties. The data will act as the data we use to create our material:

AFRAME.registerShader('custom', {
  schema: {
    emissive: {default: '#000'},
    wireframe: {default: false}
  }
});

Example — Basic Materials

To create a custom material, we have the init and update handlers set and update this.material to the desired material. Here is an example of registering a THREE.LinedDashedMaterial:

AFRAME.registerShader('line-dashed', {
  schema: {
    dashSize: {default: 3},
    lineWidth: {default: 1}
  },

  /**
   * `init` used to initialize material. Called once.
   */
  init: function (data) {
    this.material = new THREE.LineDashedMaterial(data);
    this.update(data);  // `update()` currently not called after `init`. (#1834)
  },

  /**
   * `update` used to update the material. Called on initialization and when data updates.
   */
  update: function (data) {
    this.material.dashsize = data.dashsize;
    this.material.linewidth = data.linewidth;
  }
});

Example — GLSL and Shaders

For more customized visual effects, we can write GLSL shaders and apply them to A-Frame entities. We’ll do this using THREE.ShaderMaterial and a custom component. GLSL shaders can also be used with the registerShader API, but for many cases — here, we need a tick() handler to update the shader’s clock — using a component can be easier.

NOTE: GLSL, the syntax used to write shaders, may seem a bit scary at first. For a gentle (and free!) introduction, we recommend The Book of Shaders.

Component:

// material-grid-glitch.js

const vertexShader = `
  /// PLACEHOLDER ///
`;
const fragmentShader = `
  /// PLACEHOLDER ///
`;

AFRAME.registerComponent('material-grid-glitch', {
  schema: {color: {type: 'color'}},

  /**
   * Creates a new THREE.ShaderMaterial using the two shaders defined
   * in vertex.glsl and fragment.glsl.
   */
  init: function () {
    const data = this.data;

    this.material  = new THREE.ShaderMaterial({
      uniforms: {
        time: { value: 0.0 },
        color: { value: new THREE.Color(data.color) }
      },
      vertexShader,
      fragmentShader
    });

    this.applyToMesh();
    this.el.addEventListener('model-loaded', () => this.applyToMesh());
  },


  /**
   * Update the ShaderMaterial when component data changes.
   */
  update: function () {
    this.material.uniforms.color.value.set(this.data.color);
  },

  /**
   * Apply the material to the current entity.
   */
  applyToMesh: function() {
    const mesh = this.el.getObject3D('mesh');
    if (mesh) {
      mesh.material = this.material;
    }
  },

  /**
   * On each frame, update the 'time' uniform in the shaders.
   */
  tick: function (t) {
    this.material.uniforms.time.value = t / 1000;
  }

})

Next, we can put our shaders into the placeholders above. Every material will have two shaders: a vertex and a fragment shader.

// vertex.glsl

varying vec2 vUv;

void main() {
  vUv = uv;
  gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}

// fragment.glsl

varying vec2 vUv;
uniform vec3 color;
uniform float time;

void main() {
  // Use sin(time), which curves between 0 and 1 over time,
  // to determine the mix of two colors:
  //    (a) Dynamic color where 'R' and 'B' channels come
  //        from a modulus of the UV coordinates.
  //    (b) Base color.
  //
  // The color itself is a vec4 containing RGBA values 0-1.
  gl_FragColor = mix(
    vec4(mod(vUv , 0.05) * 20.0, 1.0, 1.0),
    vec4(color, 1.0),
    sin(time)
  );
}

Finally, here is the HTML markup to put it all together:

<!-- index.html -->

<a-scene>
  <a-sphere material-grid-glitch="color: blue;"
            radius="0.5"
            position="0 1.5 -2">
  </a-sphere>
</a-scene>

• Live demo
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For a more advanced example, try realtime vertex displacement.