{"topic":{"id":6630,"title":"关于 2.2 软光栅渲染器渲染结果问题","slug":"topic","userId":1507,"categoryId":56,"createdAt":"2023-10-23 03:37:57.473765","bumpedAt":"2023-10-24 14:08:59.521227","views":374,"postsCount":4,"highestPostNumber":6,"likeCount":0,"closed":true,"pinned":false,"pinnedGlobally":false,"pinnedAt":null,"pinnedUntil":null,"isBanner":false,"excerpt":"会出现这样的问题有一些部分是黑色的没有渲染成功这是哪里出了问题呢","deletedAt":null,"isAnonymous":false,"isPrivate":false,"isMembersOnly":false,"category":{"id":56,"name":"计算机图形学","slug":"cg","color":"92278F"},"author":{"id":1507,"username":"rain","name":"rain","avatarUrl":null},"realAuthor":{"id":1507,"username":"rain","name":"rain","avatarUrl":null},"tags":[]},"posts":[{"id":14346,"postNumber":1,"raw":"会出现这样的问题\n![图片|458x365](/uploads/image/c8/0c/c80c91014c2c924b6f4aa2713d2ed59eb227400abef5c5643e5989490e9685c2.avif)\n\n\n有一些部分是黑色的没有渲染成功这是哪里出了问题呢","cooked":"

会出现这样的问题
\n $\"图片\"$

有一些部分是黑色的没有渲染成功这是哪里出了问题呢

\n","createdAt":"2023-10-23 03:37:57.618551","updatedAt":"2023-10-23 12:15:27.951926","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":36,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":3,"publicVersion":3,"deletedAt":null,"isAnonymous":false,"user":{"id":1507,"username":"rain","name":"rain","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":14353,"postNumber":3,"raw":"感觉像是某些地方的点最后的 color 值计算有些问题，同学可以输出一下自己中间计算过程中的某些数据看一看，感觉有些值好像算成 0 了","cooked":"

感觉像是某些地方的点最后的 color 值计算有些问题，同学可以输出一下自己中间计算过程中的某些数据看一看，感觉有些值好像算成 0 了

\n","createdAt":"2023-10-23 06:54:56.985808","updatedAt":"2023-10-25 03:17:06.45865","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":59,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1488,"username":"roland","name":"李昌洲","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":14363,"postNumber":5,"raw":"这是精度问题吗有一根线不太对\n![图片|438x389](/uploads/image/3c/45/3c458deb84c4de2a802221b69ced88909f8ed1c1a225d71e6bee99e702ae4445.avif)\n当移动整体的 z 值是发现渲染结果正确","cooked":"

这是精度问题吗有一根线不太对
\n $\"图片\"$
\n当移动整体的 z 值是发现渲染结果正确

\n","createdAt":"2023-10-23 09:41:34.333283","updatedAt":"2023-10-25 00:41:30.523774","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":35,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":2,"publicVersion":2,"deletedAt":null,"isAnonymous":false,"user":{"id":1507,"username":"rain","name":"rain","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":14406,"postNumber":6,"raw":"> 这是精度问题吗有一根线不太对\n\n图中那条线上都是黑色或白色，所以我也赞成 roland 的思路，应该是深度而非着色出问题了。\n\n要验证这个猜想，你可以考虑在 `render` 函数的最后直接将 z-buffer 的值归一化并作为灰度复制到 color buffer 中（也就是 RGB 分量都设置为深度值），输出一张深度图，然后看看深度图上是否也有一条过渡不平滑的线。\n\n如果深度图也不正常，那你就可以大致定位一下不正确的图像区域，然后通过加条件（特定的屏幕坐标范围）输出日志的方式检查这个区域里深度被更新的过程，进而试图找到深度算错的片元是怎么回事。如果深度图正常，那你可以试着取消光栅化器按照重心坐标差值法线的操作，直接取顶点平均值作为面片上所有片元的法向，再去排查着色的问题。","cooked":"

\n
这是精度问题吗有一根线不太对
\n

图中那条线上都是黑色或白色，所以我也赞成 roland 的思路，应该是深度而非着色出问题了。

要验证这个猜想，你可以考虑在 render 函数的最后直接将 z-buffer 的值归一化并作为灰度复制到 color buffer 中（也就是 RGB 分量都设置为深度值），输出一张深度图，然后看看深度图上是否也有一条过渡不平滑的线。

如果深度图也不正常，那你就可以大致定位一下不正确的图像区域，然后通过加条件（特定的屏幕坐标范围）输出日志的方式检查这个区域里深度被更新的过程，进而试图找到深度算错的片元是怎么回事。如果深度图正常，那你可以试着取消光栅化器按照重心坐标差值法线的操作，直接取顶点平均值作为面片上所有片元的法向，再去排查着色的问题。

\n","createdAt":"2023-10-24 14:08:11.638353","updatedAt":"2023-10-24 14:08:59.505056","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":294,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":3,"publicVersion":3,"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":5,"hasUrlPostNumber":true}