webgl: 新 app — 说需求→gemma 流式生成可交互 WebGL 小程序

左 sidebar 聊天说需求，右主区 运行/代码 两 tab。后端 SSE 流式把
gemma 生成的自包含纯原生 WebGL HTML 一段段回吐，前端实时显示代码、
写完丢进沙箱 iframe 跑。完全无状态（迭代靠前端回传 current_code）。
给儿子体验 WebGL。

apps/webgl/frontend/src/App.vue

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+<script setup lang="ts">
+import { computed, nextTick, ref, watch } from 'vue'
+import { extractHtml } from './lib/extract'
+
+interface Msg {
+  role: 'user' | 'assistant'
+  content: string
+}
+
+const EXAMPLES = [
+  '一个会转的彩色立方体，鼠标拖动可以转',
+  '满屏的星空粒子，慢慢往前飞',
+  '能用鼠标在画布上画发光线条',
+  '一片随风起伏的彩虹色波浪',
+  '点一下屏幕就放一个会弹跳的小球',
+  '一个跟着鼠标转的霓虹甜甜圈',
+]
+
+const messages = ref<Msg[]>([])
+const input = ref('')
+const busy = ref(false)
+const error = ref<string | null>(null)
+
+// 流式累积的原始文本（代码 tab 实时显示），以及结束后提取的可运行 HTML
+const code = ref('')
+const runningHtml = ref('')
+const tab = ref<'player' | 'code'>('player')
+const iframeKey = ref(0)
+
+const threadEl = ref<HTMLElement | null>(null)
+const codeEl = ref<HTMLElement | null>(null)
+const iframeEl = ref<HTMLIFrameElement | null>(null)
+
+const canSend = computed(() => !busy.value && input.value.trim().length > 0)
+const hasProgram = computed(() => runningHtml.value.length > 0)
+const lineCount = computed(() => (code.value ? code.value.split('\n').length : 0))
+
+watch([messages, busy], async () => {
+  await nextTick()
+  threadEl.value?.scrollTo({ top: threadEl.value.scrollHeight, behavior: 'smooth' })
+}, { deep: true })
+
+// 流式时让代码视图自动滚到底，像在“看它写代码”
+watch(code, async () => {
+  if (tab.value !== 'code') return
+  await nextTick()
+  codeEl.value?.scrollTo({ top: codeEl.value.scrollHeight })
+})
+
+function useExample(ex: string) {
+  if (busy.value) return
+  input.value = ex
+  send()
+}
+
+async function send() {
+  if (!canSend.value) return
+  const prompt = input.value.trim()
+  input.value = ''
+  error.value = null
+  messages.value.push({ role: 'user', content: prompt })
+  busy.value = true
+  code.value = ''
+  tab.value = 'code' // 切到代码 tab 看它一行行生成
+
+  const payload: { prompt: string; current_code?: string } = { prompt }
+  if (runningHtml.value) payload.current_code = runningHtml.value
+
+  try {
+    const res = await fetch('/api/generate', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(payload),
+    })
+    if (!res.ok || !res.body) {
+      throw new Error((await res.text().catch(() => '')) || `HTTP ${res.status}`)
+    }
+    await consumeSse(res.body)
+  } catch (e) {
+    const msg = (e as Error).message
+    error.value = msg
+    messages.value.push({ role: 'assistant', content: `出错了：${msg}` })
+  } finally {
+    busy.value = false
+  }
+}
+
+/** 读 fetch 流，解析 SSE 帧（event/data），驱动 code / runningHtml。 */
+async function consumeSse(body: ReadableStream<Uint8Array>) {
+  const reader = body.getReader()
+  const decoder = new TextDecoder()
+  let buf = ''
+  for (;;) {
+    const { value, done } = await reader.read()
+    if (done) break
+    buf += decoder.decode(value, { stream: true })
+    let sep: number
+    while ((sep = buf.indexOf('\n\n')) !== -1) {
+      const frame = buf.slice(0, sep)
+      buf = buf.slice(sep + 2)
+      handleFrame(frame)
+    }
+  }
+}
+
+function handleFrame(frame: string) {
+  let event = 'message'
+  const dataLines: string[] = []
+  for (const raw of frame.split('\n')) {
+    const line = raw.replace(/\r$/, '')
+    if (line.startsWith('event:')) event = line.slice(6).trim()
+    else if (line.startsWith('data:')) dataLines.push(line.slice(5).replace(/^ /, ''))
+  }
+  const data = dataLines.join('\n')
+  if (event === 'error') {
+    let msg = data
+    try { msg = JSON.parse(data).message ?? data } catch { /* keep raw */ }
+    error.value = msg
+    messages.value.push({ role: 'assistant', content: `出错了：${msg}` })
+    return
+  }
+  if (event === 'done') {
+    finishGeneration()
+    return
+  }
+  // 普通文本片段
+  try {
+    const t = JSON.parse(data).t
+    if (typeof t === 'string') code.value += t
+  } catch { /* 忽略坏帧 */ }
+}
+
+function finishGeneration() {
+  const html = extractHtml(code.value)
+  if (!html) {
+    error.value = '生成的内容里没找到可运行的 HTML，再换个说法试试？'
+    messages.value.push({ role: 'assistant', content: error.value })
+    return
+  }
+  runningHtml.value = html
+  iframeKey.value++
+  tab.value = 'player'
+  messages.value.push({ role: 'assistant', content: '✓ 生成好了，已经在运行 — 想改就接着说。' })
+}
+
+function rerun() {
+  iframeKey.value++
+}
+
+function goFullscreen() {
+  iframeEl.value?.requestFullscreen?.()
+}
+
+async function copyCode() {
+  try {
+    await navigator.clipboard.writeText(code.value)
+  } catch { /* 不支持就算了 */ }
+}
+
+function downloadHtml() {
+  const blob = new Blob([runningHtml.value || code.value], { type: 'text/html' })
+  const url = URL.createObjectURL(blob)
+  const a = document.createElement('a')
+  a.href = url
+  a.download = 'webgl-program.html'
+  a.click()
+  URL.revokeObjectURL(url)
+}
+
+function onKeydown(e: KeyboardEvent) {
+  if (e.key === 'Enter' && !e.shiftKey) {
+    e.preventDefault()
+    send()
+  }
+}
+</script>
+
+<template>
+  <div class="layout">
+    <!-- 左侧：聊天 说需求 -->
+    <aside class="sidebar">
+      <header class="brand">
+        <span class="logo" />
+        <div>
+          <strong>WebGL Studio</strong>
+          <small>说一句，AI 现场生成</small>
+        </div>
+      </header>
+
+      <div class="thread" ref="threadEl">
+        <div v-if="messages.length === 0" class="welcome">
+          <p>想做个什么小程序？用大白话说出来就行 👇</p>
+          <div class="chips">
+            <button v-for="ex in EXAMPLES" :key="ex" class="chip" :disabled="busy" @click="useExample(ex)">
+              {{ ex }}
+            </button>
+          </div>
+        </div>
+
+        <div v-for="(m, i) in messages" :key="i" :class="['bubble', m.role]">
+          {{ m.content }}
+        </div>
+
+        <div v-if="busy" class="bubble assistant typing">
+          <span /><span /><span /> 正在生成…
+        </div>
+      </div>
+
+      <footer class="composer">
+        <textarea
+          v-model="input"
+          :disabled="busy"
+          @keydown="onKeydown"
+          rows="2"
+          :placeholder="hasProgram ? '接着说想怎么改…（Enter 发送）' : '描述你想要的程序…（Enter 发送）'"
+        />
+        <button class="send" :disabled="!canSend" @click="send">{{ hasProgram ? '改' : '生成' }}</button>
+      </footer>
+    </aside>
+
+    <!-- 右侧：主区 tabs -->
+    <main class="main">
+      <nav class="tabs">
+        <button :class="{ active: tab === 'player' }" @click="tab = 'player'">▶ 运行</button>
+        <button :class="{ active: tab === 'code' }" @click="tab = 'code'">
+          &lt;/&gt; 代码<span v-if="lineCount" class="count">{{ lineCount }} 行</span>
+        </button>
+        <div class="spacer" />
+        <template v-if="tab === 'player' && hasProgram">
+          <button class="ghost" @click="rerun" title="重新运行">↻ 重跑</button>
+          <button class="ghost" @click="goFullscreen" title="全屏">⛶ 全屏</button>
+        </template>
+        <template v-else-if="tab === 'code' && code">
+          <button class="ghost" @click="copyCode">⧉ 复制</button>
+          <button class="ghost" @click="downloadHtml">↓ 下载</button>
+        </template>
+      </nav>
+
+      <section class="stage">
+        <!-- Player -->
+        <div v-show="tab === 'player'" class="player">
+          <iframe
+            v-if="hasProgram"
+            :key="iframeKey"
+            ref="iframeEl"
+            :srcdoc="runningHtml"
+            sandbox="allow-scripts allow-pointer-lock"
+            allow="fullscreen; accelerometer; gyroscope; xr-spatial-tracking"
+            title="生成的 WebGL 程序"
+          />
+          <div v-else class="placeholder">
+            <div class="big">▶</div>
+            <p v-if="busy">正在生成，写完自动在这里跑起来…</p>
+            <p v-else>左边说个需求，生成好的程序会在这里运行。</p>
+          </div>
+        </div>
+
+        <!-- Code -->
+        <div v-show="tab === 'code'" class="codewrap" ref="codeEl">
+          <pre v-if="code" class="code"><code>{{ code }}</code><span v-if="busy" class="caret" /></pre>
+          <div v-else class="placeholder small">
+            <p>这里会实时显示 AI 写的代码。</p>
+          </div>
+        </div>
+      </section>
+
+      <div v-if="error" class="errorbar">{{ error }}</div>
+    </main>
+  </div>
+</template>
+
+<style scoped>
+.layout {
+  display: grid;
+  grid-template-columns: 360px 1fr;
+  height: 100vh;
+  height: 100dvh;
+}
+
+/* ---- sidebar ---- */
+.sidebar {
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
+  background: var(--bg-soft);
+  border-right: 1px solid var(--border);
+}
+.brand {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 14px 16px;
+  border-bottom: 1px solid var(--border);
+}
+.logo {
+  width: 28px;
+  height: 28px;
+  border-radius: 8px;
+  background: linear-gradient(135deg, var(--accent), var(--accent-2));
+  box-shadow: 0 0 14px rgba(124, 58, 237, 0.5);
+}
+.brand strong { display: block; font-size: 1rem; }
+.brand small { color: var(--fg-dim); font-size: 0.78rem; }
+
+.thread {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
+  padding: 14px;
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+.welcome { color: var(--fg-dim); font-size: 0.9rem; }
+.welcome p { margin-bottom: 12px; }
+.chips { display: flex; flex-direction: column; gap: 8px; }
+.chip {
+  text-align: left;
+  background: rgba(255, 255, 255, 0.04);
+  border: 1px solid var(--border);
+  color: var(--fg);
+  border-radius: 10px;
+  padding: 9px 12px;
+  font-size: 0.86rem;
+  cursor: pointer;
+  transition: background 0.15s, border-color 0.15s, transform 0.1s;
+}
+.chip:hover:not(:disabled) { background: rgba(124, 58, 237, 0.16); border-color: var(--accent); transform: translateX(2px); }
+.chip:disabled { opacity: 0.5; cursor: default; }
+
+.bubble {
+  max-width: 92%;
+  padding: 9px 12px;
+  border-radius: 12px;
+  line-height: 1.45;
+  font-size: 0.9rem;
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+.bubble.user { align-self: flex-end; background: linear-gradient(135deg, var(--accent), #4f46e5); color: #fff; }
+.bubble.assistant { align-self: flex-start; background: rgba(255, 255, 255, 0.07); border: 1px solid var(--border); }
+.bubble.typing { display: inline-flex; align-items: center; gap: 5px; color: var(--fg-dim); }
+.bubble.typing span {
+  width: 6px; height: 6px; border-radius: 50%;
+  background: var(--accent-2); animation: bounce 1.2s infinite;
+}
+.bubble.typing span:nth-child(2) { animation-delay: 0.15s; }
+.bubble.typing span:nth-child(3) { animation-delay: 0.3s; }
+@keyframes bounce { 0%,60%,100% { transform: translateY(0); opacity: 0.5; } 30% { transform: translateY(-5px); opacity: 1; } }
+
+.composer {
+  display: flex;
+  gap: 8px;
+  padding: 12px;
+  border-top: 1px solid var(--border);
+  align-items: flex-end;
+}
+.composer textarea {
+  flex: 1;
+  resize: none;
+  background: rgba(255, 255, 255, 0.05);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 9px 11px;
+  color: inherit;
+  font: inherit;
+  font-size: 0.9rem;
+  line-height: 1.4;
+}
+.composer textarea:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
+.send {
+  background: linear-gradient(135deg, var(--accent), var(--accent-2));
+  color: #fff; border: none; border-radius: 10px;
+  padding: 11px 18px; font-weight: 700; cursor: pointer; white-space: nowrap;
+}
+.send:disabled { background: rgba(255, 255, 255, 0.1); color: var(--fg-dim); cursor: not-allowed; }
+
+/* ---- main ---- */
+.main { display: flex; flex-direction: column; min-width: 0; min-height: 0; }
+.tabs {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px 12px;
+  border-bottom: 1px solid var(--border);
+}
+.tabs > button {
+  background: transparent;
+  border: 1px solid transparent;
+  color: var(--fg-dim);
+  padding: 7px 14px;
+  border-radius: 8px;
+  font-size: 0.9rem;
+  font-weight: 600;
+  cursor: pointer;
+}
+.tabs > button.active { background: rgba(255, 255, 255, 0.07); color: var(--fg); border-color: var(--border); }
+.tabs .count {
+  margin-left: 6px;
+  font-size: 0.72rem;
+  color: var(--fg-dim);
+  font-weight: 500;
+}
+.spacer { flex: 1; }
+.ghost {
+  background: transparent;
+  border: 1px solid var(--border);
+  color: var(--fg-dim);
+  padding: 6px 11px;
+  border-radius: 8px;
+  font-size: 0.82rem;
+  cursor: pointer;
+}
+.ghost:hover { color: var(--fg); border-color: var(--accent); }
+
+.stage { flex: 1; min-height: 0; position: relative; }
+.player, .codewrap { position: absolute; inset: 0; }
+.player iframe { width: 100%; height: 100%; border: 0; display: block; background: #000; }
+
+.codewrap { overflow: auto; background: #0a0c12; }
+.code {
+  margin: 0;
+  padding: 16px 18px;
+  font-family: ui-monospace, 'SF Mono', 'Cascadia Code', Menlo, Consolas, monospace;
+  font-size: 0.82rem;
+  line-height: 1.55;
+  color: #c8d3e8;
+  white-space: pre-wrap;
+  word-break: break-word;
+  tab-size: 2;
+}
+.caret {
+  display: inline-block;
+  width: 8px; height: 1.05em;
+  vertical-align: text-bottom;
+  background: var(--accent-2);
+  animation: blink 1s steps(2) infinite;
+}
+@keyframes blink { 50% { opacity: 0; } }
+
+.placeholder {
+  position: absolute; inset: 0;
+  display: flex; flex-direction: column; align-items: center; justify-content: center;
+  gap: 12px; color: var(--fg-dim); text-align: center; padding: 24px;
+}
+.placeholder .big { font-size: 3.2rem; opacity: 0.35; }
+.placeholder.small { position: static; height: 100%; }
+
+.errorbar {
+  padding: 9px 14px;
+  background: rgba(251, 113, 133, 0.14);
+  border-top: 1px solid var(--rose);
+  color: var(--rose);
+  font-size: 0.85rem;
+}
+
+@media (max-width: 860px) {
+  .layout { grid-template-columns: 1fr; grid-template-rows: 1fr auto; }
+  .sidebar { order: 2; border-right: none; border-top: 1px solid var(--border); max-height: 46vh; }
+  .main { order: 1; }
+}
+</style>

apps/webgl/frontend/src/lib/extract.ts

@@ -0,0 +1,36 @@
+/**
+ * 从 LLM 生成的原始文本里抠出可运行的 HTML 文档。
+ *
+ * gemma 大多数时候会乖乖只吐 HTML，但偶尔会：
+ *  - 用 ```html ... ``` 围栏包起来
+ *  - 在前面/后面加一两句寒暄
+ * 这里尽量稳地把中间那坨 HTML 提出来。提不出来就返回空串（让调用方报错）。
+ */
+export function extractHtml(raw: string): string {
+  if (!raw) return ''
+  let s = raw.trim()
+
+  // 1. 优先取 markdown 代码围栏里的内容
+  const fence = s.match(/```(?:html|HTML)?\s*\n([\s\S]*?)```/)
+  if (fence && fence[1].trim()) {
+    s = fence[1].trim()
+  } else if (s.startsWith('```')) {
+    // 围栏没闭合（流式被截断 / 只有开头）—— 去掉开头那行围栏
+    s = s.replace(/^```[a-zA-Z]*\s*\n?/, '').replace(/```\s*$/, '').trim()
+  }
+
+  // 2. 从第一个 <!doctype 或 <html 开始截（丢掉前面的寒暄）
+  const startMatch = s.match(/<!doctype html>|<html[\s>]/i)
+  if (startMatch && startMatch.index !== undefined && startMatch.index > 0) {
+    s = s.slice(startMatch.index)
+  }
+
+  // 3. 截到最后一个 </html> 结束（丢掉后面的寒暄）
+  const endIdx = s.toLowerCase().lastIndexOf('</html>')
+  if (endIdx !== -1) {
+    s = s.slice(0, endIdx + '</html>'.length)
+  }
+
+  // 兜底：至少得像个 HTML（有标签），否则当作没提到
+  return /<[a-z!][\s\S]*>/i.test(s) ? s.trim() : ''
+}

apps/webgl/frontend/src/main.ts

@@ -0,0 +1,5 @@
+import { createApp } from 'vue'
+import App from './App.vue'
+import './style.css'
+
+createApp(App).mount('#app')

apps/webgl/frontend/src/style.css

@@ -0,0 +1,31 @@
+:root {
+  --bg: #0b0d14;
+  --bg-soft: #11141d;
+  --fg: #e6e8ee;
+  --fg-dim: #8b93a7;
+  --accent: #7c3aed;
+  --accent-2: #06b6d4;
+  --border: #1f2433;
+  --green: #34d399;
+  --amber: #fbbf24;
+  --rose: #fb7185;
+  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', system-ui, 'Helvetica Neue', sans-serif;
+  color-scheme: dark;
+}
+
+* {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+html, body, #app {
+  height: 100%;
+}
+
+body {
+  background: var(--bg);
+  color: var(--fg);
+  -webkit-font-smoothing: antialiased;
+  overflow: hidden;
+}