How to get an int as input and project a double as output in an OpenGL C++ program?

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?

score 3 · Answer 1 · edited May 23 '17 at 12:31

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.

score 0 · Answer 2 · answered Jul 25 '15 at 15:47

Your job can be split into two part

Taking integer input from user
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

OP never said anything about GLUT. – RamblingMad Jul 25 '15 at 16:03 — RamblingMad, Jul 25 '15 at 16:03
OP never said anything about 'NO GLUT' too. – Ratul Sharker Jul 25 '15 at 16:08 — Ratul Sharker, Jul 25 '15 at 16:08

score 0 · Answer 3 · answered Jul 25 '15 at 15:59

0

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/

answered Jul 25 '15 at 15:59

Alex L

115
11

how does that relates to openGL ? :P Oh I get it, you needed console along with opengl window :). As far As i know every IDE allow having the console opened and at same time opengl window (and also the final executable get the same, you need to explicitly deploy your code as "console application") – CoffeDeveloper Jul 26 '15 at 10:12

How to get an int as input and project a double as output in an OpenGL C++ program?

3 Answers3