/* * SPDX-FileCopyrightText: syuilo and misskey-project * SPDX-License-Identifier: AGPL-3.0-only */ export class SnowfallEffect { private VERTEX_SOURCE = `#version 300 es in vec4 a_position; in vec4 a_color; in vec3 a_rotation; in vec3 a_speed; in float a_size; out vec4 v_color; out float v_rotation; uniform float u_time; uniform mat4 u_projection; uniform vec3 u_worldSize; uniform float u_gravity; uniform float u_wind; uniform float u_spin_factor; uniform float u_turbulence; void main() { v_color = a_color; v_rotation = a_rotation.x + (u_time * u_spin_factor) * a_rotation.y; vec3 pos = a_position.xyz; pos.x = mod(pos.x + u_time + u_wind * a_speed.x, u_worldSize.x * 2.0) - u_worldSize.x; pos.y = mod(pos.y - u_time * a_speed.y * u_gravity, u_worldSize.y * 2.0) - u_worldSize.y; pos.x += sin(u_time * a_speed.z * u_turbulence) * a_rotation.z; pos.z += cos(u_time * a_speed.z * u_turbulence) * a_rotation.z; gl_Position = u_projection * vec4(pos.xyz, a_position.w); gl_PointSize = (a_size / gl_Position.w) * 100.0; } `; private FRAGMENT_SOURCE = `#version 300 es precision highp float; in vec4 v_color; in float v_rotation; uniform sampler2D u_texture; out vec4 out_color; void main() { vec2 rotated = vec2( cos(v_rotation) * (gl_PointCoord.x - 0.5) + sin(v_rotation) * (gl_PointCoord.y - 0.5) + 0.5, cos(v_rotation) * (gl_PointCoord.y - 0.5) - sin(v_rotation) * (gl_PointCoord.x - 0.5) + 0.5 ); vec4 snowflake = texture(u_texture, rotated); out_color = vec4(snowflake.rgb * v_color.xyz, snowflake.a * v_color.a); } `; private gl: WebGLRenderingContext; private program: WebGLProgram; private canvas: HTMLCanvasElement; private buffers: Record; private uniforms: Record; private texture: WebGLTexture; private camera: { fov: number; near: number; far: number; aspect: number; z: number; }; private wind: { current: number; force: number; target: number; min: number; max: number; easing: number; }; private time: { start: number; previous: number; } = { start: 0, previous: 0, }; private raf = 0; private density: number = 1 / 90; private depth = 100; private count = 1000; private gravity = 100; private speed: number = 1 / 10000; private color: number[] = [1, 1, 1]; private opacity = 1; private size = 4; private snowflake = 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'; private mode = 'snow'; private INITIAL_BUFFERS = () => ({ position: { size: 3, value: [] }, color: { size: 4, value: [] }, size: { size: 1, value: [] }, rotation: { size: 3, value: [] }, speed: { size: 3, value: [] }, }); private INITIAL_UNIFORMS = () => ({ time: { type: 'float', value: 0 }, worldSize: { type: 'vec3', value: [0, 0, 0] }, gravity: { type: 'float', value: this.gravity }, wind: { type: 'float', value: 0 }, spin_factor: { type: 'float', value: this.mode === 'sakura' ? 8 : 1 }, turbulence: { type: 'float', value: this.mode === 'sakura' ? 2 : 1 }, projection: { type: 'mat4', value: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], }, }); private UNIFORM_SETTERS = { int: 'uniform1i', float: 'uniform1f', vec2: 'uniform2fv', vec3: 'uniform3fv', vec4: 'uniform4fv', mat2: 'uniformMatrix2fv', mat3: 'uniformMatrix3fv', mat4: 'uniformMatrix4fv', }; private CAMERA = { fov: 60, near: 5, far: 10000, aspect: 1, z: 100, }; private WIND = { current: 0, force: 0.01, target: 0.01, min: 0, max: 0.125, easing: 0.0005, }; /** * @throws {Error} - Thrown when it fails to get WebGL context for the canvas */ constructor(options: { sakura?: boolean; }) { if (options.sakura) { this.mode = 'sakura'; this.snowflake = 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this.size = 10; this.density = 1 / 280; } const canvas = this.initCanvas(); const gl = canvas.getContext('webgl2', { antialias: true }); if (gl == null) throw new Error('Failed to get WebGL context'); document.body.append(canvas); this.canvas = canvas; this.gl = gl; this.program = this.initProgram(); this.buffers = this.initBuffers(); this.uniforms = this.initUniforms(); this.texture = this.initTexture(); this.camera = this.initCamera(); this.wind = this.initWind(); this.resize = this.resize.bind(this); this.update = this.update.bind(this); window.addEventListener('resize', () => this.resize()); } private initCanvas(): HTMLCanvasElement { const canvas = document.createElement('canvas'); Object.assign(canvas.style, { position: 'fixed', top: 0, left: 0, width: '100vw', height: '100vh', background: 'transparent', 'pointer-events': 'none', 'z-index': 2147483647, }); return canvas; } private initCamera() { return { ...this.CAMERA }; } private initWind() { return { ...this.WIND }; } private initShader(type, source): WebGLShader { const { gl } = this; const shader = gl.createShader(type); if (shader == null) throw new Error('Failed to create shader'); gl.shaderSource(shader, source); gl.compileShader(shader); return shader; } private initProgram(): WebGLProgram { const { gl } = this; const vertex = this.initShader(gl.VERTEX_SHADER, this.VERTEX_SOURCE); const fragment = this.initShader(gl.FRAGMENT_SHADER, this.FRAGMENT_SOURCE); const program = gl.createProgram(); if (program == null) throw new Error('Failed to create program'); gl.attachShader(program, vertex); gl.attachShader(program, fragment); gl.linkProgram(program); gl.useProgram(program); return program; } private initBuffers(): SnowfallEffect['buffers'] { const { gl, program } = this; const buffers = this.INITIAL_BUFFERS() as unknown as SnowfallEffect['buffers']; for (const [name, buffer] of Object.entries(buffers)) { buffer.location = gl.getAttribLocation(program, `a_${name}`); buffer.ref = gl.createBuffer()!; gl.bindBuffer(gl.ARRAY_BUFFER, buffer.ref); gl.enableVertexAttribArray(buffer.location); gl.vertexAttribPointer( buffer.location, buffer.size, gl.FLOAT, false, 0, 0, ); } return buffers; } private updateBuffers() { const { buffers } = this; for (const name of Object.keys(buffers)) { this.setBuffer(name); } } private setBuffer(name: string, value?) { const { gl, buffers } = this; const buffer = buffers[name]; buffer.value = new Float32Array(value ?? buffer.value); gl.bindBuffer(gl.ARRAY_BUFFER, buffer.ref); gl.bufferData(gl.ARRAY_BUFFER, buffer.value, gl.STATIC_DRAW); } private initUniforms(): SnowfallEffect['uniforms'] { const { gl, program } = this; const uniforms = this.INITIAL_UNIFORMS() as unknown as SnowfallEffect['uniforms']; for (const [name, uniform] of Object.entries(uniforms)) { uniform.location = gl.getUniformLocation(program, `u_${name}`)!; } return uniforms; } private updateUniforms() { const { uniforms } = this; for (const name of Object.keys(uniforms)) { this.setUniform(name); } } private setUniform(name: string, value?) { const { gl, uniforms } = this; const uniform = uniforms[name]; const setter = this.UNIFORM_SETTERS[uniform.type]; const isMatrix = /^mat[2-4]$/i.test(uniform.type); uniform.value = value ?? uniform.value; if (isMatrix) { gl[setter](uniform.location, false, uniform.value); } else { gl[setter](uniform.location, uniform.value); } } private initTexture() { const { gl } = this; const texture = gl.createTexture(); if (texture == null) throw new Error('Failed to create texture'); const image = new Image(); gl.bindTexture(gl.TEXTURE_2D, texture); gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([0, 0, 0, 0]), ); image.onload = () => { gl.bindTexture(gl.TEXTURE_2D, texture); gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image, ); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE); }; image.src = this.snowflake; return texture; } private initSnowflakes(vw: number, vh: number, dpi: number) { const position: number[] = []; const color: number[] = []; const size: number[] = []; const rotation: number[] = []; const speed: number[] = []; const height = 1 / this.density; const width = (vw / vh) * height; const depth = this.depth; const count = this.count; const length = (vw / vh) * count; for (let i = 0; i < length; ++i) { position.push( -width + Math.random() * width * 2, -height + Math.random() * height * 2, Math.random() * depth * 2, ); speed.push(1 + Math.random(), 1 + Math.random(), Math.random() * 10); rotation.push( Math.random() * 2 * Math.PI, Math.random() * 20, Math.random() * 10, ); color.push(...this.color, 0.1 + Math.random() * this.opacity); //size.push((this.size * Math.random() * this.size * vh * dpi) / 1000); size.push((this.size * vh * dpi) / 1000); } this.setUniform('worldSize', [width, height, depth]); this.setBuffer('position', position); this.setBuffer('color', color); this.setBuffer('rotation', rotation); this.setBuffer('size', size); this.setBuffer('speed', speed); } private setProjection(aspect: number) { const { camera } = this; camera.aspect = aspect; const fovRad = (camera.fov * Math.PI) / 180; const f = Math.tan(Math.PI * 0.5 - 0.5 * fovRad); const rangeInv = 1.0 / (camera.near - camera.far); const m0 = f / camera.aspect; const m5 = f; const m10 = (camera.near + camera.far) * rangeInv; const m11 = -1; const m14 = camera.near * camera.far * rangeInv * 2 + camera.z; const m15 = camera.z; return [m0, 0, 0, 0, 0, m5, 0, 0, 0, 0, m10, m11, 0, 0, m14, m15]; } public render() { const { gl } = this; gl.enable(gl.BLEND); gl.enable(gl.CULL_FACE); gl.blendFunc(gl.SRC_ALPHA, gl.ONE); gl.disable(gl.DEPTH_TEST); this.updateBuffers(); this.updateUniforms(); this.resize(true); this.time = { start: window.performance.now(), previous: window.performance.now(), }; if (this.raf) window.cancelAnimationFrame(this.raf); this.raf = window.requestAnimationFrame(this.update); return this; } private resize(updateSnowflakes = false) { const { canvas, gl } = this; const vw = canvas.offsetWidth; const vh = canvas.offsetHeight; const aspect = vw / vh; const dpi = window.devicePixelRatio; canvas.width = vw * dpi; canvas.height = vh * dpi; gl.viewport(0, 0, vw * dpi, vh * dpi); gl.clearColor(0, 0, 0, 0); if (updateSnowflakes === true) { this.initSnowflakes(vw, vh, dpi); } this.setUniform('projection', this.setProjection(aspect)); } private update(timestamp: number) { const { gl, buffers, wind } = this; const elapsed = (timestamp - this.time.start) * this.speed; const delta = timestamp - this.time.previous; gl.clear(gl.COLOR_BUFFER_BIT); gl.drawArrays( gl.POINTS, 0, buffers.position.value.length / buffers.position.size, ); if (Math.random() > 0.995) { wind.target = (wind.min + Math.random() * (wind.max - wind.min)) * (Math.random() > 0.5 ? -1 : 1); } wind.force += (wind.target - wind.force) * wind.easing; wind.current += wind.force * (delta * 0.2); this.setUniform('wind', wind.current); this.setUniform('time', elapsed); this.time.previous = timestamp; this.raf = window.requestAnimationFrame(this.update); } }