相机框架和对象框架 [英] Camera Frame and Object Frame

问题描述

我正在阅读Interactive Graphics，特别是我开始了关于查看的部分，并且我对这句话不甚了解：

最初，我们将模型视图矩阵设置为单位矩阵，因此相机框架和对象框架是相同的。

我知道什么是模型视图矩阵，并且我知道在这种情况下，摄像机视图面向z轴负向。但我不明白对象框和相框之间的区别。

感谢帮助。

解决方案

您有2个矩阵：查看和模型其中视图表示您从哪里看以及哪些方向（相机）和模型表示你的对象在哪里以及如何定向你正在渲染的。

然而，为了加速渲染，我们只使用一个累积矩阵： / p>

  ModelView = Inverse（View）* Model 
  

$例如，当你在 OpenGL 中写这样的内容时：

  glMatrixMode（GL_MODELVIEW）; 
 glLoadIdentity（）; 
  

然后查看和模型矩阵是相同的并且等于单位矩阵。在此之后，您可以将您的增量旋转和翻译添加到 View （逆顺序和方向），或者添加到 Model 订单和方向）。

更多信息请参阅：

• 了解4x4同质转换矩阵

尤其那里的最后3个链接......

I'm reading about Interactive Graphics , in particular I started the section about the viewing and I did not understand well this sentence :

Initially, we start with the model-view matrix set to an identity matrix, so the camera frame and the object frame are identical.

I know what is a model view matrix and I know that in this case the camera view is oriented in the z negative axis. But I did not understand exactly what is the difference between the object frame and the camera frame.

Thanks for the help.

解决方案

you got 2 matrices: View and Model where View represents where from are you looking and in which directions (camera) and Model represents where is and how oriented your object you are currently rendering is.

However To speed-up rendering we are using just one cumulative matrix so:

ModelView = Inverse(View) * Model

so for example when you write something like this in OpenGL:

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

Then both View and Model matrices are identical and equal to unit matrix. After this point you add your incremental rotations and translations either to View (inverse order and direction) or to Model (normal order and direction).

For more info see:

• Understanding 4x4 homogenous transform matrices

Especially the last 3 links in there...

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