问题
I have designed a 3D model in .obj format and imported using min3d framework. Its a cube with different colors. I want to give a Toast with a message for a particular color when the side of that particular color is touched. How do I do this in android 1.6 ?
回答1:
I'm not sure about the particulars in android/OpenGL-es, but in general:
You have to calculate a line that starts at the camera's position and passes through the screen coordinate pressed/clicked/etc and determine where that line intersects your object.
It's called... ah yes: "picking". Googling for "opengl picking" turned up a tutorial or three:
http://www.lighthouse3d.com/opengl/picking/
http://gpwiki.org/index.php/OpenGL:Tutorials:Picking ...
I just googled "opengl picking". Those two are the first two links, the next is a FAQ entry, followed by another tutorial. You get the idea.
Once you know what its called, finding information gets much easier. Good hunting.
来源：https://stackoverflow.com/questions/3942230/how-to-detect-the-area-of-touch-in-open-gl-es-in-android