How to color the faces of a box geometry using a shader in ThreeJS

Two flowers that represent React and ThreeJS, beneath them sits the text "Box Geometry Colored Faces Shader."

A step by step tutorial on coloring the faces of a box geometry using a shader in ThreeJS using ReactJS.

We recommend that you clone our Open Source React-Redux Starter Project, checking out the tutorial/three-js/starter branch and carrying out the steps below. The changes can be found on the tutorial/three-js/cube-colored-faces-shader-material branch.

Box Geometry Faces & Vertices

An illustration that demonstrates how the vertices are broken down by face on a box geometry.

The diagram above describes what vertex applies to what face within a box geometry and the color that we applied to each face as part of this tutorial.

Tutorial

Step One: Setup the Project

A screenshot of Chrome showing that the orbit controls work and that the cube can now be seen from different angles and distances.

Follow the tutorials below to learn how to create a ThreeJS project that implements a shader on a box geometry, which can be explored using Orbit Controls.

Step Two: Set the Vertex Colors

A screenshot of VSCode showing how we created a Float32Array that holds the colors for each vertex.

Create a Float32Array array that holds the 24 colors for the cube.

If you wish to set specific colors for each vertex, consult the diagram above the tutorial.

Step Three: Set the Color Attribute

A screenshot of VSCode showing how to set the colors as an attribute of the shader.

Apply the colors to the shader by setting them as an attribute using code similar to the one below.

const colorAttribute = new THREE.BufferAttribute(colors, 3); // 3 components (RGB) per vertexgeometry.setAttribute("aVertexColor", colorAttribute);

Step Four: Update Shaders

A screenshot of VSCode showing the updated Vertex and Fragment shader.

Update the vertex and fragment shader to work with the attribute.

Vertex Shader

Fragment Shader

Step Five: Test

A screenshot of Chrome showing a cube with colored faces that match the colors we set for the vertices in this tutorial.

Run the code and confirm the shader works as expected.

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