magic-pixels
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1.0.1 • Public • Published

Magic pixels

Magic pixels is a WebGL 3D library, which was originally developed under the name colorful-pixels at SinnerSchrader.

As I left the company, development work will be continued in this fork.

Why yet another WebGL library?

To be honest, there really is no need to build our own 3D library. There are many of these already out there. This is actually a project by Lea, and she decided building something like that anyway, just in order to learn how all this works.

Features

  • An API that is somewhat familiar to THREE
  • Vector, Matrix classes
  • a Renderer which renders Meshes
  • a Mesh contains a BufferGeometry and a Material,
  • a Material is what's a RawShaderMaterial in THREE, it has uniform variables, vertex and fragment shaders and a drawMode
  • the drawMode is one of those WebGL constants gl.TRIANGLES, gl.POINTS, gl.LINES...
  • the BufferGeometry API is also similar to three.js
  • Helpers for creating orthographic, perspective projection matrices
  • A Stopwatch class for timing (like performance.now() but with the possibility to start/stop)
  • One-Liners (mix, clamp)
  • Basic geometries (plane geometry, box geometry, sphere geometry and a custom geometry)

API documentation

Getting started

  • First, add it to your project via npm install magic-pixels.
  • Add a <canvas> element to your DOM
  • Initialize the WebGL renderer
  • Add a resize event handler
  • create a scene, consisting of Meshes (a scene is an array of meshes)

Initialize Renderer

const canvas = document.querySelector('canvas');
const renderer = new Renderer(canvas);
renderer.setSize(innerWidth, innerHeight);

Create a geometry

// creates a plane geometry of width 2x2 with 3 width segments and 3 height segments
const planeGeometry = createPlaneGeometry(2, 2, 3, 3);

// creates a box geometry of width 1x1x1 with 3 width segments, height segments and depth segments
const boxGeometry = createBoxGeometry(1, 1, 1, 2, 2, 2);

// create a sphere geometry with 16 rings and 16 sides per ring
const sphereGeometry = createSphereGeometry(1, 1, 16, 16);

Create a material

A material contains a vertexShader, a fragmentShader, a drawMode and a uniforms object. When a mesh is initialized, the uniforms object is wrapped by a ES6 Proxy, so the state in the gl context is automatically updated.

The default drawMode is gl.TRIANGLES, see MDN:drawArrays for more options.

const material = createShaderMaterial(vertexShader, fragmentShader, {
  time: 0,
  resolution: [800, 600],
  color: Color.fromHex('#ff00ff'),
});

// There are some predefined materials:

// just red
const defaultMaterial = createDefaultMaterial();
// just pink
const basicMaterial = createBasicMaterial('#ff00ff');
// the normals
const normalMaterial = createNormalMaterial();

Create a mesh and render

const mesh = new Mesh(geometry, material);

// currently, the scene is just an array of meshes:
const scene = [mesh];

// render:
renderer.render(scene);

Camera

const camera = new Camera();
camera.position.set(0, 0, 5);
camera.target.set(0, -0.5, 0);
camera.update();
console.log('camera matrix:', camera.cameraMatrix);
console.log('view matrix:', camera.viewMatrix);
// the view matrix is the inverse of the camera matrix
// you can pass these into the material.uniforms object.

Perspective projection

The camera (currently) does not do projection by itself, but you can create a perspective projection matrix:

const fieldOfView = 70;
const aspectRatio = innerWidth / innerHeight;
const near = 0.01;
const far = 100;
material.uniforms.projectionMatrix = perspective(
  fieldOfView,
  aspectRatio,
  near,
  far
);

Vector/matrix arithmetics

magic-pixels provide basic vector and matrix arithmetics classes. You can use the mul method on the Matrix class for matrix multiplication.

const a = new Vector(1, 0, 0);
const b = new Vector(0, 1, 0);
const c = a.cross(b);
const d = a.add(b);

Create translation Matrices

// identity matrix
const identity = Mat4.identity();
// translate object in space
const translationMatrix = Mat4.translation(tx, ty, tz);
// rotation matrix
const DEG = Math.PI / 180;
const rX = Mat4.rotX(30 * DEG);
const rZ = Mat4.rotY(45 * DEG);
const rZ = Mat4.rotZ(-5 * DEG);
const rotationMatrix = rX.mul(rY).mul(rZ);

Color helper

The color helper converts a hex color string to a GLSL-friendly vec3 or vec4 value.

const color = Color.fromHex('#ff00ff');
// returns a Color with {red = 255, green = 0, blue = 255, alpha = 255}
color.toVec3();
// returns [1, 0, 1]
color.toVec4();
// returns [1, 0, 1, 1]

Examples on Codepen

Trigger Warning: these examples can cause sickness to people with motion sensitivities.

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npm i magic-pixels

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Version

1.0.1

License

MIT

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Collaborators

  • lea.rosema