如何做检测对象在OpenGL的Andr​​oid？ [英] how to do Object detection in opengl Android?

问题描述

我已经开始与OpenGL ES的Andr​​oid的，因为2周，尝试3D的例子后，我在obect检测stuckup。
点¯x之间基本上映射，屏幕y坐标为X，Y，三维空间和副Z A反之亦然。

I've started with OpenGl es for Android since 2 weeks and after trying 3D examples I'm stuckup at obect detection. Basically mapping between x,y coordinates of screen to x,y,z of 3d space and vice a versa.

我碰到：

GLU.gluProject（物objx，objY，objZ，型号，modelOffset，项目，projectOffset，查看，viewOffset，赢，winOffset）;

GLU.gluUnProject（WINX，酒味，winZ，型号，modelOffset，项目，projectOffset，查看，viewOffset，OBJ，objOffset）;

但我无法理解的我如何准确使用它们

在此先感谢，如果你可以用合适的例子详细说明。 ：）

Thanks in advance if you can elaborate with suitable example. :)

推荐答案

好吧，如果你有你的矩阵准备好了，你可以这样做：

Well, if you have your matrices ready, you can do this:

float[] modelView = float[16];
float[] projection = float[16];
float[] view = {0, 0, 640, 480}; // viewport
float x = mouseX, y = mouseY, z = -1; 
// those are the inputs

float[] pos = new float[4]; 

GLU.gluUnProject(x, y, z, 
                modelView, 0, 
                projection, 0, 
                world.view().get_size(), 0, 
                pos, 0);

System.out.println("position of mouse in 3D is (" + pos[0] + ", " + pos[1] + ", " + pos[2] + ")");

如果你要选择的对象，你可以调用gluUnProject（）两次，第一次与Z = -1和Z = 1。这让你在远近飞机鼠标位置一次。减去他们获得一个视图方向，使用第一个为原点，并且已经得到了自己一个很好的光线追踪任务（对象选择）。

If you want to select objects, you call gluUnProject() twice, once with z = -1 and once with z = 1. That gives you mouse positions at the near and far planes. Subtract them to get a view direction, use the first as an origin, and you have got yourself a nice raytracing task (object selection).

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