<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source to the Rust file `widgetry/src/backend_glow.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>backend_glow.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../light.css"  id="themeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled ><script src="../../storage.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../favicon.svg">
<link rel="alternate icon" type="image/png" href="../../favicon-16x16.png">
<link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><style type="text/css">#crate-search{background-image:url("../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">&#9776;</div><a href='../../widgetry/index.html'><div class='logo-container rust-logo'><img src='../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><span class="help-button">?</span>
                <a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1">  1</span>
<span id="2">  2</span>
<span id="3">  3</span>
<span id="4">  4</span>
<span id="5">  5</span>
<span id="6">  6</span>
<span id="7">  7</span>
<span id="8">  8</span>
<span id="9">  9</span>
<span id="10"> 10</span>
<span id="11"> 11</span>
<span id="12"> 12</span>
<span id="13"> 13</span>
<span id="14"> 14</span>
<span id="15"> 15</span>
<span id="16"> 16</span>
<span id="17"> 17</span>
<span id="18"> 18</span>
<span id="19"> 19</span>
<span id="20"> 20</span>
<span id="21"> 21</span>
<span id="22"> 22</span>
<span id="23"> 23</span>
<span id="24"> 24</span>
<span id="25"> 25</span>
<span id="26"> 26</span>
<span id="27"> 27</span>
<span id="28"> 28</span>
<span id="29"> 29</span>
<span id="30"> 30</span>
<span id="31"> 31</span>
<span id="32"> 32</span>
<span id="33"> 33</span>
<span id="34"> 34</span>
<span id="35"> 35</span>
<span id="36"> 36</span>
<span id="37"> 37</span>
<span id="38"> 38</span>
<span id="39"> 39</span>
<span id="40"> 40</span>
<span id="41"> 41</span>
<span id="42"> 42</span>
<span id="43"> 43</span>
<span id="44"> 44</span>
<span id="45"> 45</span>
<span id="46"> 46</span>
<span id="47"> 47</span>
<span id="48"> 48</span>
<span id="49"> 49</span>
<span id="50"> 50</span>
<span id="51"> 51</span>
<span id="52"> 52</span>
<span id="53"> 53</span>
<span id="54"> 54</span>
<span id="55"> 55</span>
<span id="56"> 56</span>
<span id="57"> 57</span>
<span id="58"> 58</span>
<span id="59"> 59</span>
<span id="60"> 60</span>
<span id="61"> 61</span>
<span id="62"> 62</span>
<span id="63"> 63</span>
<span id="64"> 64</span>
<span id="65"> 65</span>
<span id="66"> 66</span>
<span id="67"> 67</span>
<span id="68"> 68</span>
<span id="69"> 69</span>
<span id="70"> 70</span>
<span id="71"> 71</span>
<span id="72"> 72</span>
<span id="73"> 73</span>
<span id="74"> 74</span>
<span id="75"> 75</span>
<span id="76"> 76</span>
<span id="77"> 77</span>
<span id="78"> 78</span>
<span id="79"> 79</span>
<span id="80"> 80</span>
<span id="81"> 81</span>
<span id="82"> 82</span>
<span id="83"> 83</span>
<span id="84"> 84</span>
<span id="85"> 85</span>
<span id="86"> 86</span>
<span id="87"> 87</span>
<span id="88"> 88</span>
<span id="89"> 89</span>
<span id="90"> 90</span>
<span id="91"> 91</span>
<span id="92"> 92</span>
<span id="93"> 93</span>
<span id="94"> 94</span>
<span id="95"> 95</span>
<span id="96"> 96</span>
<span id="97"> 97</span>
<span id="98"> 98</span>
<span id="99"> 99</span>
<span id="100">100</span>
<span id="101">101</span>
<span id="102">102</span>
<span id="103">103</span>
<span id="104">104</span>
<span id="105">105</span>
<span id="106">106</span>
<span id="107">107</span>
<span id="108">108</span>
<span id="109">109</span>
<span id="110">110</span>
<span id="111">111</span>
<span id="112">112</span>
<span id="113">113</span>
<span id="114">114</span>
<span id="115">115</span>
<span id="116">116</span>
<span id="117">117</span>
<span id="118">118</span>
<span id="119">119</span>
<span id="120">120</span>
<span id="121">121</span>
<span id="122">122</span>
<span id="123">123</span>
<span id="124">124</span>
<span id="125">125</span>
<span id="126">126</span>
<span id="127">127</span>
<span id="128">128</span>
<span id="129">129</span>
<span id="130">130</span>
<span id="131">131</span>
<span id="132">132</span>
<span id="133">133</span>
<span id="134">134</span>
<span id="135">135</span>
<span id="136">136</span>
<span id="137">137</span>
<span id="138">138</span>
<span id="139">139</span>
<span id="140">140</span>
<span id="141">141</span>
<span id="142">142</span>
<span id="143">143</span>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
<span id="312">312</span>
<span id="313">313</span>
<span id="314">314</span>
<span id="315">315</span>
<span id="316">316</span>
<span id="317">317</span>
<span id="318">318</span>
<span id="319">319</span>
<span id="320">320</span>
<span id="321">321</span>
<span id="322">322</span>
<span id="323">323</span>
<span id="324">324</span>
<span id="325">325</span>
<span id="326">326</span>
<span id="327">327</span>
<span id="328">328</span>
<span id="329">329</span>
<span id="330">330</span>
<span id="331">331</span>
<span id="332">332</span>
<span id="333">333</span>
<span id="334">334</span>
<span id="335">335</span>
<span id="336">336</span>
<span id="337">337</span>
<span id="338">338</span>
<span id="339">339</span>
<span id="340">340</span>
<span id="341">341</span>
<span id="342">342</span>
<span id="343">343</span>
<span id="344">344</span>
<span id="345">345</span>
<span id="346">346</span>
<span id="347">347</span>
<span id="348">348</span>
<span id="349">349</span>
<span id="350">350</span>
<span id="351">351</span>
<span id="352">352</span>
<span id="353">353</span>
<span id="354">354</span>
<span id="355">355</span>
<span id="356">356</span>
<span id="357">357</span>
<span id="358">358</span>
<span id="359">359</span>
<span id="360">360</span>
<span id="361">361</span>
<span id="362">362</span>
<span id="363">363</span>
<span id="364">364</span>
<span id="365">365</span>
<span id="366">366</span>
<span id="367">367</span>
<span id="368">368</span>
<span id="369">369</span>
<span id="370">370</span>
<span id="371">371</span>
<span id="372">372</span>
<span id="373">373</span>
<span id="374">374</span>
<span id="375">375</span>
<span id="376">376</span>
<span id="377">377</span>
<span id="378">378</span>
<span id="379">379</span>
<span id="380">380</span>
<span id="381">381</span>
<span id="382">382</span>
<span id="383">383</span>
<span id="384">384</span>
<span id="385">385</span>
<span id="386">386</span>
<span id="387">387</span>
<span id="388">388</span>
<span id="389">389</span>
<span id="390">390</span>
<span id="391">391</span>
<span id="392">392</span>
<span id="393">393</span>
<span id="394">394</span>
<span id="395">395</span>
<span id="396">396</span>
<span id="397">397</span>
<span id="398">398</span>
<span id="399">399</span>
<span id="400">400</span>
<span id="401">401</span>
<span id="402">402</span>
<span id="403">403</span>
<span id="404">404</span>
<span id="405">405</span>
<span id="406">406</span>
<span id="407">407</span>
<span id="408">408</span>
<span id="409">409</span>
<span id="410">410</span>
<span id="411">411</span>
<span id="412">412</span>
<span id="413">413</span>
<span id="414">414</span>
<span id="415">415</span>
<span id="416">416</span>
<span id="417">417</span>
<span id="418">418</span>
<span id="419">419</span>
<span id="420">420</span>
<span id="421">421</span>
<span id="422">422</span>
<span id="423">423</span>
<span id="424">424</span>
<span id="425">425</span>
<span id="426">426</span>
<span id="427">427</span>
<span id="428">428</span>
<span id="429">429</span>
<span id="430">430</span>
<span id="431">431</span>
<span id="432">432</span>
<span id="433">433</span>
<span id="434">434</span>
<span id="435">435</span>
<span id="436">436</span>
<span id="437">437</span>
<span id="438">438</span>
<span id="439">439</span>
<span id="440">440</span>
<span id="441">441</span>
<span id="442">442</span>
<span id="443">443</span>
<span id="444">444</span>
<span id="445">445</span>
<span id="446">446</span>
<span id="447">447</span>
<span id="448">448</span>
<span id="449">449</span>
<span id="450">450</span>
<span id="451">451</span>
<span id="452">452</span>
<span id="453">453</span>
<span id="454">454</span>
<span id="455">455</span>
<span id="456">456</span>
<span id="457">457</span>
<span id="458">458</span>
<span id="459">459</span>
<span id="460">460</span>
<span id="461">461</span>
<span id="462">462</span>
<span id="463">463</span>
<span id="464">464</span>
<span id="465">465</span>
<span id="466">466</span>
<span id="467">467</span>
<span id="468">468</span>
<span id="469">469</span>
<span id="470">470</span>
<span id="471">471</span>
<span id="472">472</span>
<span id="473">473</span>
<span id="474">474</span>
<span id="475">475</span>
<span id="476">476</span>
<span id="477">477</span>
<span id="478">478</span>
<span id="479">479</span>
<span id="480">480</span>
<span id="481">481</span>
<span id="482">482</span>
<span id="483">483</span>
<span id="484">484</span>
<span id="485">485</span>
<span id="486">486</span>
<span id="487">487</span>
<span id="488">488</span>
<span id="489">489</span>
<span id="490">490</span>
<span id="491">491</span>
<span id="492">492</span>
<span id="493">493</span>
<span id="494">494</span>
<span id="495">495</span>
<span id="496">496</span>
<span id="497">497</span>
<span id="498">498</span>
<span id="499">499</span>
<span id="500">500</span>
<span id="501">501</span>
<span id="502">502</span>
<span id="503">503</span>
<span id="504">504</span>
<span id="505">505</span>
<span id="506">506</span>
<span id="507">507</span>
<span id="508">508</span>
<span id="509">509</span>
<span id="510">510</span>
<span id="511">511</span>
<span id="512">512</span>
<span id="513">513</span>
<span id="514">514</span>
<span id="515">515</span>
<span id="516">516</span>
<span id="517">517</span>
<span id="518">518</span>
<span id="519">519</span>
<span id="520">520</span>
<span id="521">521</span>
<span id="522">522</span>
<span id="523">523</span>
<span id="524">524</span>
<span id="525">525</span>
<span id="526">526</span>
<span id="527">527</span>
<span id="528">528</span>
<span id="529">529</span>
<span id="530">530</span>
<span id="531">531</span>
<span id="532">532</span>
<span id="533">533</span>
<span id="534">534</span>
<span id="535">535</span>
<span id="536">536</span>
<span id="537">537</span>
<span id="538">538</span>
<span id="539">539</span>
<span id="540">540</span>
<span id="541">541</span>
<span id="542">542</span>
<span id="543">543</span>
<span id="544">544</span>
<span id="545">545</span>
<span id="546">546</span>
<span id="547">547</span>
<span id="548">548</span>
<span id="549">549</span>
<span id="550">550</span>
<span id="551">551</span>
<span id="552">552</span>
<span id="553">553</span>
<span id="554">554</span>
<span id="555">555</span>
<span id="556">556</span>
<span id="557">557</span>
<span id="558">558</span>
<span id="559">559</span>
<span id="560">560</span>
<span id="561">561</span>
<span id="562">562</span>
<span id="563">563</span>
<span id="564">564</span>
<span id="565">565</span>
<span id="566">566</span>
<span id="567">567</span>
<span id="568">568</span>
</pre><div class="example-wrap"><pre class="rust ">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">cell</span>::<span class="ident">Cell</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">rc</span>::<span class="ident">Rc</span>;

<span class="kw">use</span> <span class="ident">glow</span>::<span class="ident">HasContext</span>;

<span class="kw">use</span> <span class="kw">crate</span>::<span class="ident">drawing</span>::<span class="ident">Uniforms</span>;
<span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">Canvas</span>, <span class="ident">Color</span>, <span class="ident">EventCtx</span>, <span class="ident">GeomBatch</span>, <span class="ident">ScreenDims</span>, <span class="ident">ScreenRectangle</span>};

<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;native-backend&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">use</span> <span class="kw">crate</span>::<span class="ident">backend_glow_native</span>::<span class="ident">setup</span>;

<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;wasm-backend&quot;</span>)]</span>
<span class="kw">pub</span> <span class="kw">use</span> <span class="kw">crate</span>::<span class="ident">backend_glow_wasm</span>::<span class="ident">setup</span>;

<span class="comment">// Represents one frame that&#39;s gonna be drawn</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">GfxCtxInnards</span><span class="op">&lt;</span><span class="lifetime">&#39;a</span><span class="op">&gt;</span> {
    <span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="ident">glow</span>::<span class="ident">Context</span>,
    <span class="ident">program</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">Program</span>,
    <span class="ident">current_clip</span>: <span class="prelude-ty">Option</span><span class="op">&lt;</span>[<span class="ident">i32</span>; <span class="number">4</span>]<span class="op">&gt;</span>,
}

<span class="kw">impl</span><span class="op">&lt;</span><span class="lifetime">&#39;a</span><span class="op">&gt;</span> <span class="ident">GfxCtxInnards</span><span class="op">&lt;</span><span class="lifetime">&#39;a</span><span class="op">&gt;</span> {
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(
        <span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="ident">glow</span>::<span class="ident">Context</span>,
        <span class="ident">program</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">Program</span>,
    ) <span class="op">-</span><span class="op">&gt;</span> <span class="self">Self</span> {
        <span class="ident">GfxCtxInnards</span> {
            <span class="ident">gl</span>,
            <span class="ident">program</span>,
            <span class="ident">current_clip</span>: <span class="prelude-val">None</span>,
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">clear</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">color</span>: <span class="ident">Color</span>) {
        <span class="kw">unsafe</span> {
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">clear_color</span>(<span class="ident">color</span>.<span class="ident">r</span>, <span class="ident">color</span>.<span class="ident">g</span>, <span class="ident">color</span>.<span class="ident">b</span>, <span class="ident">color</span>.<span class="ident">a</span>);
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">clear</span>(<span class="ident">glow</span>::<span class="ident">COLOR_BUFFER_BIT</span>);

            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">clear_depth_f32</span>(<span class="number">1.0</span>);
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">clear</span>(<span class="ident">glow</span>::<span class="ident">DEPTH_BUFFER_BIT</span>);
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">redraw</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">obj</span>: <span class="kw-2">&amp;</span><span class="ident">Drawable</span>, <span class="ident">uniforms</span>: <span class="kw-2">&amp;</span><span class="ident">Uniforms</span>, <span class="kw">_</span>: <span class="kw-2">&amp;</span><span class="ident">PrerenderInnards</span>) {
        <span class="kw">unsafe</span> {
            <span class="kw">let</span> <span class="ident">transform_loc</span> <span class="op">=</span> <span class="self">self</span>
                .<span class="ident">gl</span>
                .<span class="ident">get_uniform_location</span>(<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">program</span>, <span class="string">&quot;transform&quot;</span>)
                .<span class="ident">unwrap</span>();
            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">uniform_3_f32_slice</span>(<span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="ident">transform_loc</span>), <span class="kw-2">&amp;</span><span class="ident">uniforms</span>.<span class="ident">transform</span>);
            <span class="kw">let</span> <span class="ident">window_loc</span> <span class="op">=</span> <span class="self">self</span>
                .<span class="ident">gl</span>
                .<span class="ident">get_uniform_location</span>(<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">program</span>, <span class="string">&quot;window&quot;</span>)
                .<span class="ident">unwrap</span>();
            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">uniform_3_f32_slice</span>(<span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="ident">window_loc</span>), <span class="kw-2">&amp;</span><span class="ident">uniforms</span>.<span class="ident">window</span>);

            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_vertex_array</span>(<span class="prelude-val">Some</span>(<span class="ident">obj</span>.<span class="ident">vert_array</span>.<span class="ident">id</span>));
            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">draw_elements</span>(<span class="ident">glow</span>::<span class="ident">TRIANGLES</span>, <span class="ident">obj</span>.<span class="ident">num_indices</span>, <span class="ident">glow</span>::<span class="ident">UNSIGNED_INT</span>, <span class="number">0</span>);
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_vertex_array</span>(<span class="prelude-val">None</span>);
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">enable_clipping</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">rect</span>: <span class="ident">ScreenRectangle</span>, <span class="ident">scale_factor</span>: <span class="ident">f64</span>, <span class="ident">canvas</span>: <span class="kw-2">&amp;</span><span class="ident">Canvas</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">current_clip</span>.<span class="ident">is_none</span>());
        <span class="comment">// The scissor rectangle is in units of physical pixles, as opposed to logical pixels</span>
        <span class="kw">let</span> <span class="ident">left</span> <span class="op">=</span> (<span class="ident">rect</span>.<span class="ident">x1</span> <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>;
        <span class="comment">// Y-inversion</span>
        <span class="kw">let</span> <span class="ident">bottom</span> <span class="op">=</span> ((<span class="ident">canvas</span>.<span class="ident">window_height</span> <span class="op">-</span> <span class="ident">rect</span>.<span class="ident">y2</span>) <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>;
        <span class="kw">let</span> <span class="ident">width</span> <span class="op">=</span> ((<span class="ident">rect</span>.<span class="ident">x2</span> <span class="op">-</span> <span class="ident">rect</span>.<span class="ident">x1</span>) <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>;
        <span class="kw">let</span> <span class="ident">height</span> <span class="op">=</span> ((<span class="ident">rect</span>.<span class="ident">y2</span> <span class="op">-</span> <span class="ident">rect</span>.<span class="ident">y1</span>) <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>;
        <span class="kw">unsafe</span> {
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">scissor</span>(<span class="ident">left</span>, <span class="ident">bottom</span>, <span class="ident">width</span>, <span class="ident">height</span>);
        }
        <span class="self">self</span>.<span class="ident">current_clip</span> <span class="op">=</span> <span class="prelude-val">Some</span>([<span class="ident">left</span>, <span class="ident">bottom</span>, <span class="ident">width</span>, <span class="ident">height</span>]);
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">disable_clipping</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">scale_factor</span>: <span class="ident">f64</span>, <span class="ident">canvas</span>: <span class="kw-2">&amp;</span><span class="ident">Canvas</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">current_clip</span>.<span class="ident">is_some</span>());
        <span class="self">self</span>.<span class="ident">current_clip</span> <span class="op">=</span> <span class="prelude-val">None</span>;
        <span class="kw">unsafe</span> {
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">scissor</span>(
                <span class="number">0</span>,
                <span class="number">0</span>,
                (<span class="ident">canvas</span>.<span class="ident">window_width</span> <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>,
                (<span class="ident">canvas</span>.<span class="ident">window_height</span> <span class="op">*</span> <span class="ident">scale_factor</span>) <span class="kw">as</span> <span class="ident">i32</span>,
            );
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">take_clip</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">scale_factor</span>: <span class="ident">f64</span>, <span class="ident">canvas</span>: <span class="kw-2">&amp;</span><span class="ident">Canvas</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="prelude-ty">Option</span><span class="op">&lt;</span>[<span class="ident">i32</span>; <span class="number">4</span>]<span class="op">&gt;</span> {
        <span class="kw">let</span> <span class="ident">clip</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">current_clip</span><span class="question-mark">?</span>;
        <span class="self">self</span>.<span class="ident">disable_clipping</span>(<span class="ident">scale_factor</span>, <span class="ident">canvas</span>);
        <span class="prelude-val">Some</span>(<span class="ident">clip</span>)
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">restore_clip</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">clip</span>: <span class="prelude-ty">Option</span><span class="op">&lt;</span>[<span class="ident">i32</span>; <span class="number">4</span>]<span class="op">&gt;</span>) {
        <span class="self">self</span>.<span class="ident">current_clip</span> <span class="op">=</span> <span class="ident">clip</span>;
        <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">c</span>) <span class="op">=</span> <span class="ident">clip</span> {
            <span class="kw">unsafe</span> {
                <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">scissor</span>(<span class="ident">c</span>[<span class="number">0</span>], <span class="ident">c</span>[<span class="number">1</span>], <span class="ident">c</span>[<span class="number">2</span>], <span class="ident">c</span>[<span class="number">3</span>]);
            }
        }
    }
}

<span class="doccomment">/// Geometry that&#39;s been uploaded to the GPU once and can be quickly redrawn many times. Create by</span>
<span class="doccomment">/// creating a `GeomBatch` and calling `ctx.upload(batch)`.</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Drawable</span> {
    <span class="ident">vert_array</span>: <span class="ident">VertexArray</span>,
    <span class="ident">vert_buffer</span>: <span class="ident">Buffer</span>,
    <span class="ident">elem_buffer</span>: <span class="ident">Buffer</span>,
    <span class="ident">num_indices</span>: <span class="ident">i32</span>,
    <span class="ident">gl</span>: <span class="ident">Rc</span><span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span><span class="op">&gt;</span>,
}

<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Drawable</span> {
    <span class="attribute">#[<span class="ident">inline</span>]</span>
    <span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) {
        <span class="self">self</span>.<span class="ident">elem_buffer</span>.<span class="ident">destroy</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);
        <span class="self">self</span>.<span class="ident">vert_buffer</span>.<span class="ident">destroy</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);
        <span class="self">self</span>.<span class="ident">vert_array</span>.<span class="ident">destroy</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);
    }
}

<span class="kw">impl</span> <span class="ident">Drawable</span> {
    <span class="doccomment">/// This has no effect when drawn.</span>
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">empty</span>(<span class="ident">ctx</span>: <span class="kw-2">&amp;</span><span class="ident">EventCtx</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Drawable</span> {
        <span class="ident">ctx</span>.<span class="ident">upload</span>(<span class="ident">GeomBatch</span>::<span class="ident">new</span>())
    }
}

<span class="kw">struct</span> <span class="ident">VertexArray</span> {
    <span class="ident">id</span>: <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">VertexArray</span>,
    <span class="ident">was_destroyed</span>: <span class="ident">bool</span>,
}

<span class="kw">impl</span> <span class="ident">VertexArray</span> {
    <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="ident">glow</span>::<span class="ident">Context</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">VertexArray</span> {
        <span class="kw">let</span> <span class="ident">id</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">gl</span>.<span class="ident">create_vertex_array</span>().<span class="ident">unwrap</span>() };
        <span class="ident">VertexArray</span> {
            <span class="ident">id</span>,
            <span class="ident">was_destroyed</span>: <span class="bool-val">false</span>,
        }
    }

    <span class="kw">fn</span> <span class="ident">destroy</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="ident">glow</span>::<span class="ident">Context</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="self">self</span>.<span class="ident">was_destroyed</span>, <span class="string">&quot;already destroyed&quot;</span>);
        <span class="self">self</span>.<span class="ident">was_destroyed</span> <span class="op">=</span> <span class="bool-val">true</span>;
        <span class="kw">unsafe</span> {
            <span class="ident">gl</span>.<span class="ident">delete_vertex_array</span>(<span class="self">self</span>.<span class="ident">id</span>);
        }
    }
}

<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">VertexArray</span> {
    <span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(
            <span class="self">self</span>.<span class="ident">was_destroyed</span>,
            <span class="string">&quot;failed to call `destroy` before dropped. Memory leaked.&quot;</span>
        );
    }
}

<span class="kw">struct</span> <span class="ident">Buffer</span> {
    <span class="ident">id</span>: <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">Buffer</span>,
    <span class="ident">was_destroyed</span>: <span class="ident">bool</span>,
}

<span class="kw">impl</span> <span class="ident">Buffer</span> {
    <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="ident">glow</span>::<span class="ident">Context</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Buffer</span> {
        <span class="kw">let</span> <span class="ident">id</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">gl</span>.<span class="ident">create_buffer</span>().<span class="ident">unwrap</span>() };
        <span class="ident">Buffer</span> {
            <span class="ident">id</span>,
            <span class="ident">was_destroyed</span>: <span class="bool-val">false</span>,
        }
    }

    <span class="kw">fn</span> <span class="ident">destroy</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="ident">glow</span>::<span class="ident">Context</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="self">self</span>.<span class="ident">was_destroyed</span>, <span class="string">&quot;already destroyed&quot;</span>);
        <span class="self">self</span>.<span class="ident">was_destroyed</span> <span class="op">=</span> <span class="bool-val">true</span>;
        <span class="kw">unsafe</span> { <span class="ident">gl</span>.<span class="ident">delete_buffer</span>(<span class="self">self</span>.<span class="ident">id</span>) };
    }
}

<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Buffer</span> {
    <span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) {
        <span class="macro">assert</span><span class="macro">!</span>(
            <span class="self">self</span>.<span class="ident">was_destroyed</span>,
            <span class="string">&quot;failed to call `destroy` before dropped. Memory leaked.&quot;</span>
        );
    }
}

<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;wasm-backend&quot;</span>)]</span>
<span class="kw">type</span> <span class="ident">WindowAdapter</span> <span class="op">=</span> <span class="kw">crate</span>::<span class="ident">backend_glow_wasm</span>::<span class="ident">WindowAdapter</span>;

<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">&quot;native-backend&quot;</span>)]</span>
<span class="kw">type</span> <span class="ident">WindowAdapter</span> <span class="op">=</span> <span class="kw">crate</span>::<span class="ident">backend_glow_native</span>::<span class="ident">WindowAdapter</span>;

<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">PrerenderInnards</span> {
    <span class="ident">gl</span>: <span class="ident">Rc</span><span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span><span class="op">&gt;</span>,
    <span class="ident">window_adapter</span>: <span class="ident">WindowAdapter</span>,
    <span class="ident">program</span>: <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">Program</span>,

    <span class="comment">// TODO Prerender doesn&#39;t know what things are temporary and permanent. Could make the API more</span>
    <span class="comment">// detailed.</span>
    <span class="kw">pub</span> <span class="ident">total_bytes_uploaded</span>: <span class="ident">Cell</span><span class="op">&lt;</span><span class="ident">usize</span><span class="op">&gt;</span>,
}

<span class="kw">impl</span> <span class="ident">PrerenderInnards</span> {
    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(
        <span class="ident">gl</span>: <span class="ident">glow</span>::<span class="ident">Context</span>,
        <span class="ident">program</span>: <span class="op">&lt;</span><span class="ident">glow</span>::<span class="ident">Context</span> <span class="kw">as</span> <span class="ident">glow</span>::<span class="ident">HasContext</span><span class="op">&gt;</span>::<span class="ident">Program</span>,
        <span class="ident">window_adapter</span>: <span class="ident">WindowAdapter</span>,
    ) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">PrerenderInnards</span> {
        <span class="ident">PrerenderInnards</span> {
            <span class="ident">gl</span>: <span class="ident">Rc</span>::<span class="ident">new</span>(<span class="ident">gl</span>),
            <span class="ident">program</span>,
            <span class="ident">window_adapter</span>,
            <span class="ident">total_bytes_uploaded</span>: <span class="ident">Cell</span>::<span class="ident">new</span>(<span class="number">0</span>),
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">actually_upload</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">permanent</span>: <span class="ident">bool</span>, <span class="ident">batch</span>: <span class="ident">GeomBatch</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Drawable</span> {
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">vertices</span>: <span class="ident">Vec</span><span class="op">&lt;</span>[<span class="ident">f32</span>; <span class="number">8</span>]<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>();
        <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">indices</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">u32</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>();

        <span class="kw">for</span> (<span class="ident">color</span>, <span class="ident">poly</span>, <span class="ident">z</span>) <span class="kw">in</span> <span class="ident">batch</span>.<span class="ident">consume</span>() {
            <span class="kw">let</span> <span class="ident">idx_offset</span> <span class="op">=</span> <span class="ident">vertices</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">u32</span>;
            <span class="kw">let</span> (<span class="ident">pts</span>, <span class="ident">raw_indices</span>) <span class="op">=</span> <span class="ident">poly</span>.<span class="ident">raw_for_rendering</span>();
            <span class="kw">for</span> <span class="ident">pt</span> <span class="kw">in</span> <span class="ident">pts</span> {
                <span class="kw">let</span> <span class="ident">style</span> <span class="op">=</span> <span class="ident">color</span>.<span class="ident">shader_style</span>(<span class="kw-2">*</span><span class="ident">pt</span>);
                <span class="ident">vertices</span>.<span class="ident">push</span>([
                    <span class="ident">pt</span>.<span class="ident">x</span>() <span class="kw">as</span> <span class="ident">f32</span>,
                    <span class="ident">pt</span>.<span class="ident">y</span>() <span class="kw">as</span> <span class="ident">f32</span>,
                    <span class="ident">z</span> <span class="kw">as</span> <span class="ident">f32</span>,
                    <span class="ident">style</span>[<span class="number">0</span>],
                    <span class="ident">style</span>[<span class="number">1</span>],
                    <span class="ident">style</span>[<span class="number">2</span>],
                    <span class="ident">style</span>[<span class="number">3</span>],
                    <span class="ident">style</span>[<span class="number">4</span>],
                ]);
            }
            <span class="kw">for</span> <span class="ident">idx</span> <span class="kw">in</span> <span class="ident">raw_indices</span> {
                <span class="ident">indices</span>.<span class="ident">push</span>(<span class="ident">idx_offset</span> <span class="op">+</span> (<span class="kw-2">*</span><span class="ident">idx</span> <span class="kw">as</span> <span class="ident">u32</span>));
            }
        }

        <span class="kw">let</span> (<span class="ident">vert_buffer</span>, <span class="ident">vert_array</span>, <span class="ident">elem_buffer</span>) <span class="op">=</span> <span class="kw">unsafe</span> {
            <span class="kw">let</span> <span class="ident">vert_array</span> <span class="op">=</span> <span class="ident">VertexArray</span>::<span class="ident">new</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);
            <span class="kw">let</span> <span class="ident">vert_buffer</span> <span class="op">=</span> <span class="ident">Buffer</span>::<span class="ident">new</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);
            <span class="kw">let</span> <span class="ident">elem_buffer</span> <span class="op">=</span> <span class="ident">Buffer</span>::<span class="ident">new</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>);

            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_vertex_array</span>(<span class="prelude-val">Some</span>(<span class="ident">vert_array</span>.<span class="ident">id</span>));

            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">bind_buffer</span>(<span class="ident">glow</span>::<span class="ident">ARRAY_BUFFER</span>, <span class="prelude-val">Some</span>(<span class="ident">vert_buffer</span>.<span class="ident">id</span>));
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">buffer_data_u8_slice</span>(
                <span class="ident">glow</span>::<span class="ident">ARRAY_BUFFER</span>,
                <span class="kw-2">&amp;</span><span class="ident">vertices</span>.<span class="ident">align_to</span>::<span class="op">&lt;</span><span class="ident">u8</span><span class="op">&gt;</span>().<span class="number">1</span>,
                <span class="comment">// TODO Use permanent</span>
                <span class="ident">glow</span>::<span class="ident">STATIC_DRAW</span>,
            );

            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">bind_buffer</span>(<span class="ident">glow</span>::<span class="ident">ELEMENT_ARRAY_BUFFER</span>, <span class="prelude-val">Some</span>(<span class="ident">elem_buffer</span>.<span class="ident">id</span>));
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">buffer_data_u8_slice</span>(
                <span class="ident">glow</span>::<span class="ident">ELEMENT_ARRAY_BUFFER</span>,
                <span class="kw-2">&amp;</span><span class="ident">indices</span>.<span class="ident">align_to</span>::<span class="op">&lt;</span><span class="ident">u8</span><span class="op">&gt;</span>().<span class="number">1</span>,
                <span class="ident">glow</span>::<span class="ident">STATIC_DRAW</span>,
            );

            <span class="kw">let</span> <span class="ident">vertex_attributes</span>: [<span class="ident">i32</span>; <span class="number">3</span>] <span class="op">=</span> [
                <span class="number">3</span>, <span class="comment">// position is vec2</span>
                <span class="number">4</span>, <span class="comment">// color is vec4</span>
                <span class="number">1</span>, <span class="comment">// texture_id is float</span>
            ];
            <span class="kw">let</span> <span class="ident">stride</span> <span class="op">=</span> <span class="ident">vertex_attributes</span>.<span class="ident">iter</span>().<span class="ident">sum</span>::<span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>() <span class="op">*</span> <span class="ident">std</span>::<span class="ident">mem</span>::<span class="ident">size_of</span>::<span class="op">&lt;</span><span class="ident">f32</span><span class="op">&gt;</span>() <span class="kw">as</span> <span class="ident">i32</span>;
            <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>;
            <span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">size</span>) <span class="kw">in</span> <span class="ident">vertex_attributes</span>.<span class="ident">iter</span>().<span class="ident">enumerate</span>() {
                <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">enable_vertex_attrib_array</span>(<span class="ident">i</span> <span class="kw">as</span> <span class="ident">u32</span>);
                <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">vertex_attrib_pointer_f32</span>(
                    <span class="ident">i</span> <span class="kw">as</span> <span class="ident">u32</span>,
                    <span class="kw-2">*</span><span class="ident">size</span>,
                    <span class="ident">glow</span>::<span class="ident">FLOAT</span>,
                    <span class="bool-val">false</span>,
                    <span class="ident">stride</span>,
                    <span class="ident">offset</span>,
                );
                <span class="ident">offset</span> <span class="op">+</span><span class="op">=</span> <span class="ident">size</span> <span class="op">*</span> <span class="ident">std</span>::<span class="ident">mem</span>::<span class="ident">size_of</span>::<span class="op">&lt;</span><span class="ident">f32</span><span class="op">&gt;</span>() <span class="kw">as</span> <span class="ident">i32</span>;
            }

            <span class="comment">// Safety?</span>
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_vertex_array</span>(<span class="prelude-val">None</span>);
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_buffer</span>(<span class="ident">glow</span>::<span class="ident">ARRAY_BUFFER</span>, <span class="prelude-val">None</span>);
            <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">bind_buffer</span>(<span class="ident">glow</span>::<span class="ident">ELEMENT_ARRAY_BUFFER</span>, <span class="prelude-val">None</span>);

            (<span class="ident">vert_buffer</span>, <span class="ident">vert_array</span>, <span class="ident">elem_buffer</span>)
        };
        <span class="kw">let</span> <span class="ident">num_indices</span> <span class="op">=</span> <span class="ident">indices</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">i32</span>;

        <span class="kw">if</span> <span class="ident">permanent</span> {
            <span class="comment">/*self.total_bytes_uploaded.set(
                self.total_bytes_uploaded.get()
                    + vertex_buffer.get_size()
                    + index_buffer.get_size(),
            );*/</span>
        }

        <span class="ident">Drawable</span> {
            <span class="ident">vert_array</span>,
            <span class="ident">vert_buffer</span>,
            <span class="ident">elem_buffer</span>,
            <span class="ident">num_indices</span>,
            <span class="ident">gl</span>: <span class="self">self</span>.<span class="ident">gl</span>.<span class="ident">clone</span>(),
        }
    }

    <span class="kw">fn</span> <span class="ident">window</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="kw-2">&amp;</span><span class="ident">winit</span>::<span class="ident">window</span>::<span class="ident">Window</span> {
        <span class="self">self</span>.<span class="ident">window_adapter</span>.<span class="ident">window</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">request_redraw</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) {
        <span class="self">self</span>.<span class="ident">window</span>().<span class="ident">request_redraw</span>();
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">set_cursor_icon</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">icon</span>: <span class="ident">winit</span>::<span class="ident">window</span>::<span class="ident">CursorIcon</span>) {
        <span class="self">self</span>.<span class="ident">window</span>().<span class="ident">set_cursor_icon</span>(<span class="ident">icon</span>);
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">draw_new_frame</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">GfxCtxInnards</span> {
        <span class="ident">GfxCtxInnards</span>::<span class="ident">new</span>(<span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">gl</span>, <span class="kw-2">&amp;</span><span class="self">self</span>.<span class="ident">program</span>)
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">window_resized</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">new_size</span>: <span class="ident">ScreenDims</span>, <span class="ident">scale_factor</span>: <span class="ident">f64</span>) {
        <span class="kw">let</span> <span class="ident">physical_size</span> <span class="op">=</span> <span class="ident">winit</span>::<span class="ident">dpi</span>::<span class="ident">LogicalSize</span>::<span class="ident">from</span>(<span class="ident">new_size</span>).<span class="ident">to_physical</span>(<span class="ident">scale_factor</span>);
        <span class="self">self</span>.<span class="ident">window_adapter</span>.<span class="ident">window_resized</span>(<span class="ident">new_size</span>, <span class="ident">scale_factor</span>);
        <span class="kw">unsafe</span> {
            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">viewport</span>(<span class="number">0</span>, <span class="number">0</span>, <span class="ident">physical_size</span>.<span class="ident">width</span>, <span class="ident">physical_size</span>.<span class="ident">height</span>);
            <span class="comment">// I think it&#39;s safe to assume there&#39;s not a clip right now.</span>
            <span class="self">self</span>.<span class="ident">gl</span>
                .<span class="ident">scissor</span>(<span class="number">0</span>, <span class="number">0</span>, <span class="ident">physical_size</span>.<span class="ident">width</span>, <span class="ident">physical_size</span>.<span class="ident">height</span>);
        }
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">window_size</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">scale_factor</span>: <span class="ident">f64</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">ScreenDims</span> {
        <span class="self">self</span>.<span class="ident">window</span>().<span class="ident">inner_size</span>().<span class="ident">to_logical</span>(<span class="ident">scale_factor</span>).<span class="ident">into</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">set_window_icon</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">icon</span>: <span class="ident">winit</span>::<span class="ident">window</span>::<span class="ident">Icon</span>) {
        <span class="self">self</span>.<span class="ident">window</span>().<span class="ident">set_window_icon</span>(<span class="prelude-val">Some</span>(<span class="ident">icon</span>));
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">monitor_scale_factor</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">f64</span> {
        <span class="self">self</span>.<span class="ident">window</span>().<span class="ident">scale_factor</span>()
    }

    <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">draw_finished</span>(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="ident">gfc_ctx_innards</span>: <span class="ident">GfxCtxInnards</span>) {
        <span class="self">self</span>.<span class="ident">window_adapter</span>.<span class="ident">draw_finished</span>(<span class="ident">gfc_ctx_innards</span>)
    }
}

<span class="doccomment">/// Uploads a sprite sheet of textures to the GPU so they can be used by Fill::Texture and</span>
<span class="doccomment">/// friends to paint shapes.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `path` - image file which is a grid of images.</span>
<span class="doccomment">/// `sprite_length` - the width and height of an individual cell in the image grid</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The image file can have any number of sprites, but they must all be the same size.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Once uploaded, textures are addressed by their id, starting from 1, from left to right, top to</span>
<span class="doccomment">/// bottom, like so:</span>
<span class="doccomment">///</span>
<span class="doccomment">///   ┌─┬─┬─┐</span>
<span class="doccomment">///   │1│2│3│</span>
<span class="doccomment">///   ├─┼─┼─┤</span>
<span class="doccomment">///   │4│5│6│</span>
<span class="doccomment">///   ├─┼─┼─┤</span>
<span class="doccomment">///   │7│8│9│</span>
<span class="doccomment">///   └─┴─┴─┘</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Texture(0) is reserved for a pure white (no-op) texture.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Implementation is based on the the description of ArrayTextures from:</span>
<span class="doccomment">/// https://www.khronos.org/opengl/wiki/Array_Texture.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">load_textures</span>(
    <span class="ident">gl</span>: <span class="kw-2">&amp;</span><span class="ident">glow</span>::<span class="ident">Context</span>,
    <span class="ident">filename</span>: <span class="kw-2">&amp;</span><span class="ident">str</span>,
    <span class="ident">sprite_length</span>: <span class="ident">u32</span>,
) <span class="op">-</span><span class="op">&gt;</span> <span class="prelude-ty">Result</span><span class="op">&lt;</span>(), <span class="ident">Box</span><span class="op">&lt;</span><span class="ident">dyn</span> <span class="ident">std</span>::<span class="ident">error</span>::<span class="ident">Error</span><span class="op">&gt;</span><span class="op">&gt;</span> {
    <span class="kw">let</span> <span class="ident">path</span> <span class="op">=</span> <span class="ident">abstutil</span>::<span class="ident">path</span>(<span class="ident">filename</span>);
    <span class="kw">let</span> <span class="ident">image_bytes</span> <span class="op">=</span> <span class="ident">abstutil</span>::<span class="ident">slurp_file</span>(<span class="kw-2">&amp;</span><span class="ident">path</span>)<span class="question-mark">?</span>;
    <span class="kw">let</span> <span class="ident">dynamic_img</span> <span class="op">=</span> <span class="ident">image</span>::<span class="ident">load_from_memory</span>(<span class="kw-2">&amp;</span><span class="ident">image_bytes</span>)<span class="question-mark">?</span>;
    <span class="kw">let</span> <span class="ident">img</span> <span class="op">=</span> <span class="kw">if</span> <span class="kw">let</span> <span class="ident">image</span>::<span class="ident">DynamicImage</span>::<span class="ident">ImageRgba8</span>(<span class="ident">img</span>) <span class="op">=</span> <span class="ident">dynamic_img</span> {
        <span class="ident">img</span>
    } <span class="kw">else</span> {
        <span class="macro">todo</span><span class="macro">!</span>(<span class="string">&quot;support other image formats&quot;</span>);
    };

    <span class="kw">let</span> <span class="ident">format</span> <span class="op">=</span> <span class="ident">glow</span>::<span class="ident">RGBA</span>;
    <span class="kw">let</span> <span class="ident">target</span> <span class="op">=</span> <span class="ident">glow</span>::<span class="ident">TEXTURE_2D_ARRAY</span>;
    <span class="kw">let</span> <span class="ident">mipmap_level</span> <span class="op">=</span> <span class="number">1</span>;
    <span class="kw">let</span> <span class="ident">internal_format</span> <span class="op">=</span> <span class="ident">glow</span>::<span class="ident">RGBA</span>;
    <span class="kw">let</span> <span class="ident">bytes_per_pixel</span> <span class="op">=</span> <span class="number">4</span>;

    <span class="kw">let</span> <span class="ident">texture_id</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">gl</span>.<span class="ident">create_texture</span>()<span class="question-mark">?</span> };
    <span class="kw">unsafe</span> {
        <span class="ident">gl</span>.<span class="ident">bind_texture</span>(<span class="ident">target</span>, <span class="prelude-val">Some</span>(<span class="ident">texture_id</span>));
    }

    <span class="kw">let</span> (<span class="ident">img_width</span>, <span class="ident">img_height</span>) <span class="op">=</span> <span class="ident">img</span>.<span class="ident">dimensions</span>();
    <span class="kw">let</span> <span class="ident">sprite_height</span> <span class="op">=</span> <span class="ident">sprite_length</span>;
    <span class="kw">let</span> <span class="ident">sprites_per_row</span> <span class="op">=</span> <span class="ident">img_width</span> <span class="op">/</span> <span class="ident">sprite_length</span>;
    <span class="kw">let</span> <span class="ident">sprites_per_column</span> <span class="op">=</span> <span class="ident">img_height</span> <span class="op">/</span> <span class="ident">sprite_length</span>;
    <span class="kw">let</span> <span class="ident">sprite_count</span> <span class="op">=</span> <span class="ident">sprites_per_row</span> <span class="op">*</span> <span class="ident">sprites_per_column</span>;

    <span class="macro">assert_eq</span><span class="macro">!</span>(
        <span class="ident">sprites_per_row</span> <span class="op">*</span> <span class="ident">sprite_length</span>,
        <span class="ident">img_width</span>,
        <span class="string">&quot;sprites must align exactly&quot;</span>
    );
    <span class="macro">assert_eq</span><span class="macro">!</span>(
        <span class="ident">sprites_per_column</span> <span class="op">*</span> <span class="ident">sprite_height</span>,
        <span class="ident">img_height</span>,
        <span class="string">&quot;sprites must align exactly&quot;</span>
    );

    <span class="macro">info</span><span class="macro">!</span>(
        <span class="string">&quot;img_size: {}x{}px ({} px), sprite_size: {}x{}px, sprites: {}x{} ({} sprites)&quot;</span>,
        <span class="ident">img_width</span>,
        <span class="ident">img_height</span>,
        <span class="ident">img</span>.<span class="ident">pixels</span>().<span class="ident">len</span>(),
        <span class="ident">sprite_length</span>,
        <span class="ident">sprite_height</span>,
        <span class="ident">sprites_per_row</span>,
        <span class="ident">sprites_per_column</span>,
        <span class="ident">sprite_count</span>
    );

    <span class="comment">// Allocate the storage.</span>
    <span class="kw">unsafe</span> {
        <span class="ident">gl</span>.<span class="ident">tex_storage_3d</span>(
            <span class="ident">target</span>,
            <span class="ident">mipmap_level</span>,
            <span class="ident">internal_format</span>,
            <span class="ident">sprite_length</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_height</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_count</span> <span class="kw">as</span> <span class="ident">i32</span>,
        );
    }

    <span class="comment">// Upload pixel data.</span>
    <span class="comment">//</span>
    <span class="comment">// From: https://www.khronos.org/opengl/wiki/Array_Texture#Creation_and_Management</span>
    <span class="comment">// &gt; The first 0 refers to the mipmap level (level 0, since there&#39;s only 1)</span>
    <span class="comment">// &gt; The following 2 zeroes refers to the x and y offsets in case you only want to</span>
    <span class="comment">// &gt; specify a subrectangle.</span>
    <span class="comment">// &gt; The final 0 refers to the layer index offset (we start from index 0 and have 2</span>
    <span class="comment">// &gt; levels).</span>
    <span class="comment">// &gt; Altogether you can specify a 3D box subset of the overall texture, but only one</span>
    <span class="comment">// &gt; mip level at a time.</span>
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">formatted_pixel_bytes</span>: <span class="ident">Vec</span><span class="op">&lt;</span><span class="ident">u8</span><span class="op">&gt;</span> <span class="op">=</span>
        <span class="ident">Vec</span>::<span class="ident">with_capacity</span>(<span class="ident">img</span>.<span class="ident">pixels</span>().<span class="ident">len</span>() <span class="op">*</span> <span class="ident">bytes_per_pixel</span>);

    <span class="comment">// In order to avoid branching in our shader logic, all shapes are rendered with a texture.</span>
    <span class="comment">// Even &quot;non-textured&quot; styles like Fill::Color, use a &quot;default&quot; no-op (pure white) texture,</span>
    <span class="comment">// which we generate here.</span>
    <span class="ident">formatted_pixel_bytes</span>.<span class="ident">append</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="macro">vec</span><span class="macro">!</span>[
        <span class="number">255</span>;
        (<span class="ident">sprite_length</span> <span class="op">*</span> <span class="ident">sprite_height</span>) <span class="kw">as</span> <span class="ident">usize</span>
            <span class="op">*</span> <span class="ident">bytes_per_pixel</span>
    ]);

    <span class="comment">// OpenGL texture arrays expect each texture&#39;s bytes to be contiguous, but it&#39;s conventional to</span>
    <span class="comment">// store textures in a grid within a single spritesheet image, where a row and column traverses</span>
    <span class="comment">// multiple sprites.</span>
    <span class="comment">//</span>
    <span class="comment">// For example, if we had 6 textures, A-F, the input spritesheet bytes would be like:</span>
    <span class="comment">// [[AAA, BBB, CCC],</span>
    <span class="comment">//  [AAA, BBB, CCC]</span>
    <span class="comment">//  [AAA, BBB, CCC],</span>
    <span class="comment">//  [DDD, EEE, FFF],</span>
    <span class="comment">//  [DDD, EEE, FFF],</span>
    <span class="comment">//  [DDD, EEE, FFF]]</span>
    <span class="comment">//</span>
    <span class="comment">// Which we need to convert to:</span>
    <span class="comment">// [[AAAAAAAAA],</span>
    <span class="comment">//  [BBBBBBBBB],</span>
    <span class="comment">//  [CCCCCCCCC],</span>
    <span class="comment">//  [DDDDDDDDD],</span>
    <span class="comment">//  [EEEEEEEEE],</span>
    <span class="comment">//  [FFFFFFFFF]]</span>
    <span class="kw">use</span> <span class="ident">image</span>::<span class="ident">GenericImageView</span>;
    <span class="kw">for</span> <span class="ident">y</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">sprites_per_column</span> {
        <span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">sprites_per_row</span> {
            <span class="kw">let</span> <span class="ident">sprite_cell</span> <span class="op">=</span> <span class="ident">img</span>.<span class="ident">view</span>(
                <span class="ident">x</span> <span class="op">*</span> <span class="ident">sprite_length</span>,
                <span class="ident">y</span> <span class="op">*</span> <span class="ident">sprite_height</span>,
                <span class="ident">sprite_length</span>,
                <span class="ident">sprite_height</span>,
            );
            <span class="kw">for</span> <span class="ident">p</span> <span class="kw">in</span> <span class="ident">sprite_cell</span>.<span class="ident">pixels</span>() {
                <span class="ident">formatted_pixel_bytes</span>.<span class="ident">extend_from_slice</span>(<span class="kw-2">&amp;</span><span class="ident">p</span>.<span class="number">2</span> .<span class="number">0</span>);
            }
        }
    }

    <span class="comment">// prepare and generate mipmaps</span>
    <span class="kw">unsafe</span> {
        <span class="ident">gl</span>.<span class="ident">tex_sub_image_3d</span>(
            <span class="ident">target</span>,
            <span class="number">0</span>,
            <span class="number">0</span>,
            <span class="number">0</span>,
            <span class="number">0</span>,
            <span class="ident">sprite_length</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_height</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_count</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">format</span>,
            <span class="ident">glow</span>::<span class="ident">UNSIGNED_BYTE</span>,
            <span class="ident">glow</span>::<span class="ident">PixelUnpackData</span>::<span class="ident">Slice</span>(<span class="kw-2">&amp;</span><span class="ident">formatted_pixel_bytes</span>),
        );

        <span class="ident">gl</span>.<span class="ident">tex_image_3d</span>(
            <span class="ident">target</span>,
            <span class="number">0</span>,
            <span class="ident">format</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_length</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_height</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_count</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="number">0</span>,
            <span class="ident">format</span>,
            <span class="ident">glow</span>::<span class="ident">UNSIGNED_BYTE</span>,
            <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="ident">formatted_pixel_bytes</span>),
        );
        <span class="ident">gl</span>.<span class="ident">tex_image_3d</span>(
            <span class="ident">target</span>,
            <span class="number">1</span>,
            <span class="ident">format</span> <span class="kw">as</span> <span class="ident">i32</span>,
            (<span class="ident">sprite_length</span> <span class="op">/</span> <span class="number">2</span>) <span class="kw">as</span> <span class="ident">i32</span>,
            (<span class="ident">sprite_height</span> <span class="op">/</span> <span class="number">2</span>) <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_count</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="number">0</span>,
            <span class="ident">format</span>,
            <span class="ident">glow</span>::<span class="ident">UNSIGNED_BYTE</span>,
            <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="ident">formatted_pixel_bytes</span>),
        );
        <span class="ident">gl</span>.<span class="ident">tex_image_3d</span>(
            <span class="ident">target</span>,
            <span class="number">2</span>,
            <span class="ident">format</span> <span class="kw">as</span> <span class="ident">i32</span>,
            (<span class="ident">sprite_length</span> <span class="op">/</span> <span class="number">4</span>) <span class="kw">as</span> <span class="ident">i32</span>,
            (<span class="ident">sprite_height</span> <span class="op">/</span> <span class="number">4</span>) <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="ident">sprite_count</span> <span class="kw">as</span> <span class="ident">i32</span>,
            <span class="number">0</span>,
            <span class="ident">format</span>,
            <span class="ident">glow</span>::<span class="ident">UNSIGNED_BYTE</span>,
            <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="ident">formatted_pixel_bytes</span>),
        );
        <span class="ident">gl</span>.<span class="ident">generate_mipmap</span>(<span class="ident">target</span>);
    }

    <span class="prelude-val">Ok</span>(())
}
</pre></div>
</section><section id="search" class="content hidden"></section><section class="footer"></section><script>window.rootPath = "../../";window.currentCrate = "widgetry";</script><script src="../../main.js"></script><script src="../../source-script.js"></script><script src="../../source-files.js"></script><script defer src="../../search-index.js"></script></body></html>