XenoGL is a lightweight and Object-Oriented wrapper for WebGL2.
XenoGL is under unstable yet. APIs may be going to change, which breaks your code. Do not use XenoGL for production softwares.
Download the zip file from Release page on GitHub and unzip the file.
Copy build/xenogl.min.js to your directory and append below code to your HTML file:
<script src="xenogl.min.js"></script>
<script>
// Write your code here.
</script>
Run the install command.
$ npm install xenogl --save
Then import xenogl in JavaScript file.
const XenoGL = require('xenogl');
First, create a WebGL2 context from a canvas.
// create a canvas.
const canvas = document.body.createElement('canvas');
canvas.width = 500;
canvas.height = 500;
document.body.appendChild(canvas);
// create a context.
const xgl = new XenoGL.WebGL2(canvas);
Next, create two shaders and a program. And add the program to the context.
// load source as you like.
const vertexShaderSource = await fetch('vertex_shader.glsl').then((res) => res.text());
const fragmentShaderSource = await fetch('fragment_shader.glsl').then((res) => res.text());
// create shaders.
const vertexShader = new XenoGL.VertexShader(vertexShaderSource);
const fragmentShader = new XenoGL.FragmentShader(fragmentShaderSource);
// create a program.
const program = new XenoGL.Program({
vertexShader: vertexShader,
fragmentShader: fragmentShader
});
// add the program to the context.
xgl.addProgram(program);
You need data to draw. For example, vertex positions and colors.
const vertices = new Float32Array([
-0.5, 0.5, 0.0,
-0.5, -0.5, 0.0,
0.5, 0.5, 0.0,
-0.5, -0.5, 0.0,
0.5, -0.5, 0.0,
0.5, 0.5, 0.0
]);
const colors = new Float32Array([
1.0, 0.0, 0.0, 1.0,
0.0, 1.0, 0.0, 1.0,
0.0, 0.0, 1.0, 1.0,
0.0, 1.0, 0.0, 1.0,
0.0, 0.0, 0.0, 1.0,
0.0, 0.0, 1.0, 1.0
]);
Then, create a buffer from data.
// create attributes which is defined in shaders.
const positionAttribute = new XenoGL.Attribute('vertexPosition', 3);
const colorAttribute = new XenoGL.Attribute('color', 4);
// create buffers with data and attributes.
const positionBuffer = new XenoGL.ArrayBuffer({
dataOrLength: vertices,
attributes: [positionAttribute],
dataType: XenoGL.FLOAT
});
const colorBuffer = new XenoGL.ArrayBuffer({
dataOrLength: colors,
attributes: [colorAttribute],
dataType: XenoGL.FLOAT
});
// add buffers to the program.
program.addBuffer(positionBuffer);
program.addBuffer(colorBuffer);
Finally, draw it!
xgl.draw(XenoGL.TRIANGLES);
That's all.
You can use multiple programs.
To switch programs, use activateProgram.
xgl.addProgram(updaterProgram);
xgl.addProgram(rendererProgram);
xgl.activateProgram(rendererProgram);
activateProgram is a very heavy operation. If you switch programs every frames, it causes performance issues. Because it toggles every attributes on buffers.
If you want just change the program without toggling attributes, use useProgram instead.
But if you don't have knowledge about OpenGL/WebGL, you should use activateProgram.
You can send data to buffers.
const positionBuffer = new XenoGL.ArrayBuffer({
attributes: [positionAttribute],
dataType: XenoGL.FLOAT
});
program.addBuffer(positionBuffer);
positionBuffer.bufferData(new Float32Array([1.0, 1.0, 1.0]));
To make a buffer interleaved, pass an array of attributes to constructor of ArrayBuffer.
const vertices = new Float32Array([
-30.0, 30.0, 0.0, // position
0.0, 1.0, 0.0, 1.0, // color
-30.0, -30.0, 0.0,
1.0, 0.0, 0.0, 1.0,
30.0, 30.0, 0.0,
1.0, 0.0, 0.0, 1.0,
30.0, -30.0, 0.0,
0.0, 0.0, 1.0, 1.0
]);
const positionAttribute = new XenoGL.Attribute('vertexPosition', 3);
const colorAttribute = new XenoGL.Attribute('color', 4);
const buffer = new XenoGL.ArrayBuffer({
dataOrLength: vertices,
attributes: [positionAttribute, colorAttribute],
dataType: XenoGL.FLOAT,
usage: XenoGL.DYNAMIC_DRAW
});
XenoGL detect stride and offset automatically and make the buffer interleaved.
You can create a index buffer by using XenoGL.ElementArrayBuffer object.
const indices = new Uint16Array([0, 1, 2, 1, 3, 2]);
const indexBuffer = new XenoGL.ElementArrayBuffer({
dataOrLength: indices,
dataType: XenoGL.UNSIGNED_SHORT,
usage: XenoGL.DYNAMIC_DRAW
});
program.addBuffer(indexBuffer);
An ElementArrayBuffer object is treated as an index buffer when it is added to the program.
When you add multiple ElementArrayBuffer to the program, latest one is used as an index buffer.
If you need to choose an index buffer manually, use program.activateElemntArrayBuffer().
program.activateElementArrayBuffer(firstBuffer);
Not supported yet. Stay tuned.
To create uniform variables, use XenoGL.Uniform and add it to the program.
const modelUniform = new XenoGL.Uniform('model');
const viewUniform = new XenoGL.Uniform('view');
const projectionUniform = new XenoGL.Uniform('projection');
modelUniform.setMatrix(model);
projectionUniform.setMatrix(projection);
program.addUniform(modelUniform);
program.addUniform(viewUniform);
program.addUniform(projectionUniform);
XenoGL.Uniform object has setValue(value, type), setVector(vector, type) and setMatrix(matrix) to apply a value. type can be XenoGL.FLOAT, XenoGL.UNSIGNED_SHORT and other data types.
Don't forget to add an uniform to the program.
XenoGL supports Vertex Array Object(VAO).
const buffer = new XenoGL.ArrayBuffer({
dataOrLength: particleInitialDataF32,
attributes: [positionAttr, velocityAttr, ageAttr, lifeAttr],
dataType: XenoGL.FLOAT,
usage: XenoGL.DYNAMIC_COPY
});
// 2nd arg is optional.
const vao = new XenoGL.VertexArrayObject(buffer, {
dataOrLength: particleInitialDataF32, // initial data
attributes: [positionAttr, velocityAttr] // attributes to enable
});
// add it to the program.
program.addVertexArrayObject(vao);
If you activate another VAO, use program.activateVertexArrayObject.
program.activateVertexArrayObject(vao);
Uniform Buffer Objects(UBO) make you able to share values between programs.
// create a buffer.
const sharedUniformBuffer = new XenoGL.UniformBuffer({
dataOrLength: new Float32Array([1.0, 0.0, 0.0, 1.0]),
dataType: XenoGL.FLOAT
});
// create ubos.
const ubo1 = new XenoGL.UniformBufferObject('param', sharedUniformBuffer);
const ubo2 = new XenoGL.UniformBufferObject('param', sharedUniformBuffer);
// add to programs.
program1.addUniformBufferObject(ubo1);
program2.addUniformBufferObject(ubo2);
To use transform feedbacks, first, create a program with additional options.
const program = new XenoGL.Program({
vertexShader: vs,
fragmentShader: fs,
feedbackVaryings: ['vertexPosition', 'vertexVelocity', 'vertexAge', 'vertexLife'], // variables to feedback.
feedbackBufferMode: XenoGL.INTERLEAVED_ATTRIBS // XenoGL.SEPARATE_ATTRIB or XenoGL.INTERLEAVED_ATTRIBS
});
Then, create a TransformFeedback object and add it to the context(not to the program).
const tf = new XenoGL.TransformFeedback();
xgl.addTransformFeedback(tf);
feedback method executes a calc and feedback.
tf.feedback({
mode: XenoGL.POINTS,
targetBuffers: [buffer], // buffers to feedback.
count: 100 // how many calc.
});
Using textures, create a Texture2D object and add it to the context.
const textureSource = await fetch('texture-300x300.png').then((res) => res.blob())
.then((blob) => createImageBitmap(blob));
const texture = new XenoGL.Texture2D(textureSource);
xgl.addTexture(texture);
Source of texture can be img, canvas, video, ImageBitmap, ImageData or ArrayBufferView.
You can crete textures with options.
const texture = new XenoGL.Texture2D(textureSource, {
target: XenoGL.TEXTURE_2D,
mipmapLevel: 0,
internalFormat: XenoGL.RGBA,
format: XenoGL.RGBA,
dataType: XenoGL.UNSIGNED_BYTE,
width: 500,
height: 500
});
To use another texture, use xgl.activateTexture(texture).
xgl.activateTexture(texture2);
xgl.clearColor(0.0, 0.0, 0.0, 1.0);
xgl.clear(XenoGL.COLOR_BUFFER_BIT | XenoGL.DEPTH_BUFFER_BIT);
xgl.enable(XenoGL.RASTERIZER_DISCARD);
xgl.disable(XenoGL.RASTERIZER_DISCARD);
For more information, see API Document.
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