如何在OpenGL C ++程序中获取int作为输入并投影一个double作为输出？

Question

I'm developing a OpenGL application in C++ however I require the user to input an int and the project to output a double plus some text. What would be the best way to go about this?

Answer 1

There's no text input function in OpenGL. You'll have to use an API on top of openGL, for example manage the keyboard entry with the basic GLUT keyboard functions .

For the output, you have to draw it as part of your graphic output as explained in this SO question .

Of course you don't need to reinvent the wheel from scratch and may consider more elaborate API than Glut, as discussed here .

Edit: Just seen today this tweet from Evan Todd with a link to his 160 lines of C++ implementation of in-game console on github. It's based on OpenGL/glfw. His approach could interest you as well.

Answer 2

Your job can be split into two part

1. Taking integer input from user
2. Show double + extra text it on your window

obviously second part is the easy part, use glutStrokeCharacter to show your double + text referred here

The first part is little bit tricker, you can make a TextEdit like widget using the glutStrokeCharacter & glutKeyboardFunc . The job of the TextEdit will to show the user original int input. just register the keyboard using glutKeyboardFunc & on the call back draw the original int inside the TextEdit widget.

glutKeyboardFunc is referrence here here

suggestion, draw a nice rectangle just behind the TextEdit's to make it seems actual user input :). Happy coding

Answer 3

Just found this actually which does exactly what I'm looking for. Thanks for all the responses.

https://justcheckingonall.wordpress.com/2008/08/29/console-window-win32-app/