index.js

import { mat4 } from 'https://webgpufundamentals.org/3rdparty/wgpu-matrix.module.js';
import { initializeWebGPU } from './wgpu-device.js';
import { createState } from './wgpu-state.js';
import { generateGlyphTextureAtlas, createTextureFromSource } from './wgpu-utility.js';
import { createPipeline } from './wgpu-pipeline.js';
import { fetchShaderCode } from './wgpu-shader.js';
import { generateGlyphVerticesForText } from './wgpu-text.js';
import { config } from './wgpu-config.js';
import { CANVAS, CTX, COLORS, RENDER_PASS_DESCRIPTOR } from './wgpu-constants.js';

const canvas = document.querySelector('canvas');
const state = createState(config);

async function main() {
    const adapter = await navigator.gpu?.requestAdapter();
    const { device, context, presentationFormat } = await initializeWebGPU(navigator, adapter, canvas);
    if (!device) return;

    state.device = device;

    // Load shader code
    const shaderCode = await fetchShaderCode('shaders.wgsl');
    const vertexSize = config.floatsPerVertex * 4;

    // Create pipeline
    state.pipeline = await createPipeline(state.device, presentationFormat, vertexSize, shaderCode);

    // Generate and display glyph texture atlas
    const glyphCanvas = generateGlyphTextureAtlas(CANVAS, CTX, config);
    document.body.appendChild(glyphCanvas);
    glyphCanvas.style.backgroundColor = '#222';

    // Create vertex and index buffers
    createBuffers();

    // Generate vertex buffer data and texture
    generateVertexDataAndTexture(glyphCanvas);

    // Start the game loop
    gameLoop(context);
}

function createBuffers() {
    const vertexBufferSize = config.maxGlyphs * config.vertsPerGlyph * config.floatsPerVertex * 4;
    state.vertexBuffer = state.device.createBuffer({
        label: 'vertices',
        size: vertexBufferSize,
        usage: GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST,
    });

    state.indexBuffer = state.device.createBuffer({
        label: 'indices',
        size: config.maxGlyphs * config.vertsPerGlyph * 4,
        usage: GPUBufferUsage.INDEX | GPUBufferUsage.COPY_DST,
    });

    const indices = generateIndices(config.maxGlyphs);
    state.device.queue.writeBuffer(state.indexBuffer, 0, new Uint32Array(indices));
}

function generateIndices(maxGlyphs) {
    return Array.from({ length: maxGlyphs * 6 }, (_, i) => {
        const ndx = Math.floor(i / 6) * 4;
        return (i % 6 < 3 ? [ndx, ndx + 1, ndx + 2] : [ndx + 2, ndx + 1, ndx + 3])[i % 3];
    });
}

function generateVertexDataAndTexture(glyphCanvas) {
    const { vertexData, numGlyphs, width, height } = generateGlyphVerticesForText('Hello\nworld!\nText in\nWebGPU!', COLORS, config, glyphCanvas);
    state.device.queue.writeBuffer(state.vertexBuffer, 0, vertexData);

    state.texture = createTextureFromSource(state.device, glyphCanvas, { mips: true });
    state.sampler = state.device.createSampler({
        minFilter: 'linear',
        magFilter: 'linear',
    });

    state.uniformBuffer = state.device.createBuffer({
        label: 'uniforms for quad',
        size: config.uniformBufferSize,
        usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
    });

    state.matrix = state.uniformValues.subarray(0, 16);

    state.bindGroup = state.device.createBindGroup({
        layout: state.pipeline.getBindGroupLayout(0),
        entries: [
            { binding: 0, resource: state.sampler },
            { binding: 1, resource: state.texture.createView() },
            { binding: 2, resource: { buffer: state.uniformBuffer } },
        ],
    });

    state.numGlyphs = numGlyphs;
    state.width = width;
    state.height = height;
}

function gameLoop(context) {
    let lastTime = performance.now();
    const frameInterval = 1000 / config.maxFPS;

    function tick() {
        const currentTime = performance.now();
        const deltaTime = (currentTime - lastTime) / 1000;

        if (currentTime - lastTime >= frameInterval) {
            update(deltaTime, context);
            lastTime = currentTime;
        }

        setTimeout(tick, 0);
    }

    tick();
}

function update(deltaTime, context) {
    state.time += deltaTime;

    // Set up projection and view matrices
    const fov = 60 * Math.PI / 180;
    const aspect = canvas.clientWidth / canvas.clientHeight;
    const projectionMatrix = mat4.perspective(fov, aspect, config.render.zNear, config.render.zFar);
    const viewMatrix = mat4.lookAt([0, 0, 5], [0, 0, 0], [0, 1, 0]);
    const viewProjectionMatrix = mat4.multiply(projectionMatrix, viewMatrix);
    RENDER_PASS_DESCRIPTOR.colorAttachments[0].view = context.getCurrentTexture().createView();

    const encoder = state.device.createCommandEncoder();
    const pass = encoder.beginRenderPass(RENDER_PASS_DESCRIPTOR);
    pass.setPipeline(state.pipeline);
    mat4.rotateY(viewProjectionMatrix, state.time, state.matrix);
    mat4.translate(state.matrix, [-state.width / 2, -state.height / 2, 0], state.matrix);
    state.device.queue.writeBuffer(state.uniformBuffer, 0, state.uniformValues);
    pass.setBindGroup(0, state.bindGroup);
    pass.setVertexBuffer(0, state.vertexBuffer);
    pass.setIndexBuffer(state.indexBuffer, 'uint32');
    pass.drawIndexed(state.numGlyphs * 6);
    pass.end();
    state.device.queue.submit([encoder.finish()]);
}

main();