{"topic":{"id":8157,"title":"物理模拟 2.12 last_update 的修改","slug":"topic","userId":1506,"categoryId":56,"createdAt":"2023-12-21 12:51:10.531192","bumpedAt":"2023-12-23 09:28:38.387834","views":276,"postsCount":3,"highestPostNumber":3,"likeCount":0,"closed":true,"pinned":false,"pinnedGlobally":false,"pinnedAt":null,"pinnedUntil":null,"isBanner":false,"excerpt":"last_update 无法实现+=功能以及 swapbuffer（）的具体实现是否为调用 render（）？若是，参数如何设置？","deletedAt":null,"isAnonymous":false,"isPrivate":false,"isMembersOnly":false,"category":{"id":56,"name":"计算机图形学","slug":"cg","color":"92278F"},"author":{"id":1506,"username":"1905814644","name":"喜欢我的石代码吗","avatarUrl":null},"realAuthor":{"id":1506,"username":"1905814644","name":"喜欢我的石代码吗","avatarUrl":null},"tags":[]},"posts":[{"id":19869,"postNumber":1,"raw":"last_update 无法实现+=功能\n[grid mode=\"tile\"]\n![d9ea5874ea43bab00a217999e33c4c3|689x187](/uploads/image/68/33/6833fc7cb34a112812a1c83c34f5a47d0701bd684cdba1d86f8824d480509504.avif)\n![d44d0a0083b2ea4f540b45a893d8d1f|690x348](/uploads/image/6c/80/6c809bd336125405d6d26e4f674d8bdec1f822b84698675c555a1601cb662982.avif)\n[/grid]\n以及 swapbuffer（）的具体实现是否为调用 render（）？若是，参数如何设置？","cooked":"

last_update 无法实现+=功能

$\"d9ea5874ea43bab00a217999e33c4c3\"$
\n $\"d44d0a0083b2ea4f540b45a893d8d1f\"$

以及 swapbuffer（）的具体实现是否为调用 render（）？若是，参数如何设置？

\n","createdAt":"2023-12-21 12:51:10.618022","updatedAt":"2023-12-22 03:29:19.161786","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":37,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":2,"publicVersion":2,"deletedAt":null,"isAnonymous":false,"user":{"id":1506,"username":"1905814644","name":"喜欢我的石代码吗","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":19927,"postNumber":2,"raw":"调用 update 就行","cooked":"

调用 update 就行

\n","createdAt":"2023-12-22 03:00:57.748845","updatedAt":"2023-12-22 03:00:57.748845","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":5,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1554,"username":"JJBond","name":"弃之可惜","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":19948,"postNumber":3,"raw":"[quote=\"喜欢我的石代码吗，post:1, topic:8157, username:1905814644\"]\nlast_update 无法实现+=功能\n[/quote]\n\n`time_point` 类型是一个类型别名，其全称是 `time_point>`，这表示它默认的 `duration` 存储类型是 `long`。而我们使用的 `duration` 类型全称是 `duration`，以 `float` 类型存储，因此不能直接相加，需要使用 `duration_cast` 转换。你可以用如下方法转换类型：\n\n```cpp\nduration d(1.0f);\nlast_update += duration_cast(d);\n```\n\n更多关于 `duration_cast` 的说明可见于 [std::chrono::duration_cast](https://zh.cppreference.com/w/cpp/chrono/duration/duration_cast) 。\n\n[quote=\"喜欢我的石代码吗，post:1, topic:8157, username:1905814644\"]\n以及 swapbuffer（）的具体实现是否为调用 render（）？若是，参数如何设置？\n[/quote]\n\n该问题已经有同学问过了，可以看一下这个话题：https://xjtu.app/t/topic/6641","cooked":"

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\n\t\t\t\t\t\t\t喜欢我的石代码吗，post:1, topic:8157, username:1905814644:\n\t\t\t\t\t\t

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last_update 无法实现+=功能
\n

\n\t\t\t\t

time_point 类型是一个类型别名，其全称是 time_point<steady_clock, duration<long, std::nano>>，这表示它默认的 duration 存储类型是 long。而我们使用的 duration 类型全称是 duration<float>，以 float 类型存储，因此不能直接相加，需要使用 duration_cast 转换。你可以用如下方法转换类型：

duration d(1.0f);\nlast_update += duration_cast<time_point::duration>(d);\n

更多关于 duration_cast 的说明可见于 std::chrono::duration_cast 。

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\n\t\t\t\t\t\t\t喜欢我的石代码吗，post:1, topic:8157, username:1905814644:\n\t\t\t\t\t\t

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以及 swapbuffer（）的具体实现是否为调用 render（）？若是，参数如何设置？
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该问题已经有同学问过了，可以看一下这个话题：实验 2.12 前向欧拉法模拟质点运动渲染问题

\n","createdAt":"2023-12-22 08:26:54.741473","updatedAt":"2023-12-22 08:26:54.741473","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":182,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1381,"username":"greyishsong","name":"greyishsong","avatarUrl":"/uploads/image/da/bc/dabc731b0311f59850625bbeb55ed969fcfac0430c5ef0f68441e5466b7aa496.avif","admin":false,"moderator":true,"signatureRaw":null,"signatureCooked":null}}],"hasMore":false,"lastReadPostNumber":2,"hasUrlPostNumber":true}