242 lines
7.5 KiB
JavaScript
242 lines
7.5 KiB
JavaScript
"use strict";
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var vertexShaderSource = `#version 300 es
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in vec2 a_position;
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uniform vec2 u_resolution;
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void main() {
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vec2 clipSpace = (a_position / u_resolution) * 2.0 - 1.0;
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gl_Position = vec4(clipSpace.xy, 0.0, 1.0);
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}
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`;
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var fragmentShaderSource = ` #version 300 es
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precision highp float;
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out vec4 outColor;
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uniform vec4 u_color;
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void main() {
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outColor = u_color;
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}
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`;
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function createShader(ctx, type, source) {
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var shader = ctx.createShader(type);
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if (!shader) {
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throw new Error("Couldn't create shader: " + type);
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}
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ctx.shaderSource(shader, source);
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ctx.compileShader(shader);
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var success = ctx.getShaderParameter(shader, ctx.COMPILE_STATUS);
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if (!success) {
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console.log(ctx.getShaderInfoLog(shader));
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ctx.deleteShader(shader);
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throw new Error("Couldn't compile shader: " + type);
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}
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return shader;
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}
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function createProgram(ctx, vertexShaderSource, fragmentShaderSource) {
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var program = ctx.createProgram();
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if (vertexShaderSource !== null) {
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const vs = createShader(ctx, ctx.VERTEX_SHADER, vertexShaderSource);
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ctx.attachShader(program, vs);
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}
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if (fragmentShaderSource !== null) {
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const fs = createShader(ctx, ctx.FRAGMENT_SHADER, fragmentShaderSource);
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ctx.attachShader(program, fs);
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}
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ctx.linkProgram(program);
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var success = ctx.getProgramParameter(program, ctx.LINK_STATUS);
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if (!success) {
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console.log(ctx.getProgramInfoLog(program));
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ctx.deleteProgram(program);
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throw new Error("Failed to create program!");
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}
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return program;
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}
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function createUniform(ctx, program, name) {
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const loc = ctx.getUniformLocation(program, name);
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return loc;
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}
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function initializeContext(canvasId) {
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const canvas = document.getElementById(canvasId);
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const ctx = canvas.getContext("webgl2", { antialias: false });
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return ctx;
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}
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function drawTriangle(gfx, position, exts) {
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const positionLoc = gfx.attribs.get("a_position");
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if (positionLoc === undefined)
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throw new Error("`drawTriangle` requires attribute `a_position` to be defined");
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const points = [
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position.x, position.y,
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position.x + exts.x, position.y,
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position.x, position.y + exts.y,
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];
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gfx.ctx.bindBuffer(gfx.ctx.ARRAY_BUFFER, gfx.buffer);
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gfx.ctx.enableVertexAttribArray(positionLoc);
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gfx.ctx.vertexAttribPointer(positionLoc, 2, gfx.ctx.FLOAT, false, 0, 0);
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gfx.ctx.bufferData(gfx.ctx.ARRAY_BUFFER, new Float32Array(points), gfx.ctx.STATIC_DRAW);
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gfx.ctx.bindVertexArray(gfx.vao);
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gfx.ctx.drawArrays(gfx.ctx.TRIANGLES, 0, 3);
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gfx.ctx.disableVertexAttribArray(positionLoc);
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}
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function drawRectangle(gfx, position, exts) {
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const positionLoc = gfx.attribs.get("a_position");
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if (positionLoc === undefined)
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throw new Error("`drawRectange` requires attribute `a_position` to be defined");
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const points = [
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position.x, position.y,
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position.x + exts.x, position.y,
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position.x, position.y + exts.y,
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position.x + exts.x, position.y + exts.y,
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position.x + exts.x, position.y,
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position.x, position.y + exts.y,
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];
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gfx.ctx.bindBuffer(gfx.ctx.ARRAY_BUFFER, gfx.buffer);
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gfx.ctx.enableVertexAttribArray(positionLoc);
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gfx.ctx.vertexAttribPointer(positionLoc, 2, gfx.ctx.FLOAT, false, 0, 0);
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gfx.ctx.bufferData(gfx.ctx.ARRAY_BUFFER, new Float32Array(points), gfx.ctx.STATIC_DRAW);
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gfx.ctx.bindVertexArray(gfx.vao);
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gfx.ctx.drawArrays(gfx.ctx.TRIANGLES, 0, 6);
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gfx.ctx.disableVertexAttribArray(positionLoc);
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}
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function drawCircle(gfx, position, radius) {
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const precision = 20;
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const positionLoc = gfx.attribs.get("a_position");
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if (positionLoc === undefined)
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throw new Error("`drawCircle` requires attribute `a_position` to be defined");
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const points = new Array();
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const angle = 2.0 * Math.PI / precision;
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var a = 0;
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points.push(position.x);
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points.push(position.y);
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points.push(position.x);
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points.push(position.y + radius);
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for (let i = precision; i >= 0; --i) {
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var vec = Vec2.angle(a);
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a += angle;
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}
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gfx.ctx.bindBuffer(gfx.ctx.ARRAY_BUFFER, gfx.buffer);
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gfx.ctx.enableVertexAttribArray(positionLoc);
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gfx.ctx.vertexAttribPointer(positionLoc, 2, gfx.ctx.FLOAT, false, 0, 0);
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gfx.ctx.bufferData(gfx.ctx.ARRAY_BUFFER, new Float32Array(points), gfx.ctx.STATIC_DRAW);
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gfx.ctx.bindVertexArray(gfx.vao);
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gfx.ctx.drawArrays(gfx.ctx.TRIANGLES, 0, 3 * precision);
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gfx.ctx.disableVertexAttribArray(positionLoc);
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}
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class Graphics {
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ctx;
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program;
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buffer;
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vao;
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attribs = new Map();
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uniforms = new Map();
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constructor(ctx) {
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this.ctx = ctx;
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this.program = createProgram(ctx, vertexShaderSource, fragmentShaderSource);
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this.buffer = ctx.createBuffer();
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this.vao = ctx.createVertexArray();
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ctx.bindVertexArray(this.vao);
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ctx.viewport(0, 0, ctx.canvas.width, ctx.canvas.height);
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ctx.useProgram(this.program);
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}
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clear(r, g, b, a) {
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this.ctx.clearColor(r, g, b, a);
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this.ctx.clear(this.ctx.COLOR_BUFFER_BIT);
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}
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createAttribute(name) {
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const loc = this.ctx.getAttribLocation(this.program, name);
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this.attribs.set(name, loc);
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}
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createUniform(name) {
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const loc = this.ctx.getUniformLocation(this.program, name);
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if (loc === null)
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throw new Error("Couldn't get location for uniform: " + name);
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this.uniforms.set(name, loc);
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}
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getUniform(name) {
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const loc = this.uniforms.get(name);
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if (loc === undefined)
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throw new Error("Tried to get uninitialized uniform: " + name);
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return loc;
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}
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}
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class Vec2 {
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x;
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y;
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constructor(x, y) {
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this.x = x;
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this.y = y;
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}
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add(other) {
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this.x += other.x;
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this.y += other.y;
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}
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sub(other) {
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this.x -= other.x;
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this.y -= other.y;
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}
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mult(scalar) {
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this.x *= scalar;
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this.y *= scalar;
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}
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static angle(angle) {
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const eps = 1e-6;
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let x = Math.cos(angle);
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let y = Math.sin(angle);
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if ((x > 0 && x < eps)
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|| (x < 0 && x > -eps))
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x = 0;
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if ((y > 0 && y < eps)
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|| (y < 0 && y > -eps))
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y = 0;
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return new Vec2(x, y);
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}
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}
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class Vec3 {
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x;
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y;
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z;
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constructor(x, y, z) {
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this.x = x;
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this.y = y;
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this.z = z;
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}
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add(other) {
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this.x += other.x;
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this.y += other.y;
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this.z += other.z;
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}
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sub(other) {
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this.x -= other.x;
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this.y -= other.y;
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this.z -= other.z;
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}
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}
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function fullscreenCanvas(id) {
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const canvas = document.getElementById(id);
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canvas.width = window.innerWidth;
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canvas.height = window.innerHeight;
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}
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function draw() {
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const canvasId = "game";
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fullscreenCanvas(canvasId);
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const ctx = initializeContext(canvasId);
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if (ctx === null)
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return;
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const gfx = new Graphics(ctx);
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gfx.createAttribute("a_position");
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gfx.createUniform("u_resolution");
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gfx.createUniform("u_color");
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const position = new Vec2(ctx.canvas.width / 2 - 100, ctx.canvas.height / 2 - 100);
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gfx.clear(0, 0, 0, 0);
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ctx.uniform2f(gfx.getUniform("u_resolution"), ctx.canvas.width, ctx.canvas.height);
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ctx.uniform4f(gfx.getUniform("u_color"), 0.2, 0.2, 0.2, 1);
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drawRectangle(gfx, position, new Vec2(200, 200));
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}
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(() => {
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draw();
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window.onresize = draw;
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})();
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