如何从3D点获取屏幕坐标？ Opengl [英] How to get Screen coordinates from a 3D Point? Opengl

问题描述

我已经看过很多屏幕坐标到世界坐标的帖子，但没有看到相反的。有没有一个简单的方法来获得屏幕坐标从一个3d点，从任何角度，我认为它？我使用C ++和opengl

I've seen alot of Screen-Coordinate to world coordinate posts, but have not seen the opposite. Is there an easy way of getting screen coordinates from a 3d point, from any angle I view it from? I'm using C++ and opengl

推荐答案

erjot的答案是不完整的。

erjot's answer is incomplete.

还有两件事需要考虑。

1. c $ c> homogeneous = P。 M。 world ， homogeneous 向量是均匀空间中的4-d向量。特别是，要把它带回到[-1：1] ^ 3立方体，你需要用 homogeneous.w 除它的前3个坐标。 cube.x = homogeneous.x / homogeneous.w （有些人称之为投影鸿沟）。


2. 然后，您需要通过对其应用视口变换将[-1：1] ^ 3立方体转换为窗口坐标。 window.x = viewport.x + viewport.width *（cube.x + 1）/ 2

1. with homogeneous = P . M . world, the homogeneous vector is a 4-d vector in homogeneous space. In particular, to bring it back to the [-1:1]^3 cube, you need to divide its first 3 coordinates by homogeneous.w. cube.x = homogeneous.x / homogeneous.w (what some people call the projection divide).
2. You then need to transform the [-1:1]^3 cube to window coordinates by applying the Viewport transformation to it. window.x = viewport.x + viewport.width * (cube.x+1)/2

如果你关心最后的Z，转换不是通过视口，而是DepthRange。

In case you care about the final Z, the transformation is not going through viewport, but DepthRange instead.

这篇关于如何从3D点获取屏幕坐标？ Opengl的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！