shading | 易学教程

What is the difference between Phong Shading and Gouraud Shading?

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问题 As I understand it, Gouraud shading calculates light color for each vertex and does interpolation on that color, whereas Phong shading interpolates the normal for each pixel and calculates light color based on that interpolated value. However, when I tried to derive the light color mathematically, I ended up with the same formula for both ways! (Where n1 and n2 are the normals of the two vertices, t is the coefficient for interpolation, L is the light direction, and the plane on the top and

How can I plot a single 2-D curve onto a colormap in Matlab?

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问题 I have created a smooth color gradient 2-D contour plot with existing compiled data in Matlab. I have an x-axis, y-axis, and z-data contour plotted as a colormap. My goal is to plot a 2-D curve onto the colormap, representing a single z-data value, but I don't know how. Does anyone know how to plot a 2-D curve onto a 3-D colormap? I have provided a link to the current colormap onto which I wish to plot a single z-value as a curve. Existing colormap x = 0.05:0.05:1; y = 0.0:0.05:1; [X, Y] =

Phong and Gouraud Shading WebGL

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问题 I read that that in Gouraud Shading, the color for the fragment is computed in the Vertex Shader. Whereas, in Phong Shading, the color for the fragment is computed in the Fragment Shader. In this implementation , which of these are we using ? I did not understand exactly the difference between them. Could anyone help me ? Thanks <button id = "ButtonX">Rotate X</button> <button id = "ButtonY">Rotate Y</button> <button id = "ButtonZ">Rotate Z</button> <button id = "ButtonT">Toggle Rotation<

Instagram架构的分片和ID设计

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前言每秒上传超过25张图和90个“喜欢”，在Instagram我们存了很多数据，为了确保把重要的数据都扔到内存里，达到快速响应用户的请求，我们已经开始把数据进行分片-换句话说，把数据放到更多的小桶子里，每个桶了装一部分数据。我们的应用服务器跑的是 Django 和后端是 PostgreSQL ，在决定要分片后的第一个问题是，是否还继续用 PostgreSQL 作为主要数据仓库，或者换成别的？我们评估了一些NoSQL的解决方案，但最终决定最好的解决方案是：把数据分片到不同的 PostgreSQL 数据库。在写数据到不同服务器之前，还需要解决一个问题，如何给在数据库里的每块数据都标识上唯一的标识（如，发布到我们系统的每张图）。单库好解决，就是用自增主键-但如果数据同时写到多个库就不行了，本博客将回答如果解决这个问题。开始前，先列出系统的主要实现目标：生成的ID可以按时间排序（如，一个图片列表的id，可以不用获取更多信息即可直接排序） ID最好是64位的（这样索引更小，存储的也更好，像Redis）系统最好尽可能地只有部分是“可变因素”-很大部分原因为何在很少工程师的情况下可以扩展 Instagram，就是因为我们相信简单好用！现有的解决方案很多类似的ID解决方案都有些问题，下面是一小部分例子：在web应用层生成ID 这类方法把生成ID的任务都扔到应用层实现