Jump to content
  • Advertisement


This topic is now archived and is closed to further replies.


Open GL window - scale of things inside

This topic is 6186 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello, I want to recreate a game I made for a class (had to be done in old, old turbo 3.0) in Open GL, but I am having a hard time getting the screen how I want it. I got the window to come up with the dimensions that I want (thanks to NeHe) but the inside is not scaled how I want it to be. To start off my drawing code I do this:
I then use the glTranslatef function so that the origin is at the center of the screen and that the scale of 1.0f would be about a pixel in the screen (the screen being 400x400). So, I do something like this:
glTranslatef (0.0f, 0.0f, -100.0f);
At first I thought -100.0f would be far enough away, but it turns out that a line from (0,0) to (20,20) goes across about half the screen. So, I upped the last argument in the glTranslatef some to see if I could get the line look like it was really going 20 pixels along the x- and y-axis. But, whenever I put a number greater than 100 *nothing* appears ... it is like there is a limit on how far back you can go. Does anyone understand what I am talking about? Any solutions? Thanks

Share this post

Link to post
Share on other sites
At the begging of your program set up ortho mode. (I am assuming you are doing 2d here)


0,0 will be the upper left corner, and 400,400 will be the bottom right.

I think thisis what you want.


Those who dance are considered insane by those who cannot hear the music.

Share this post

Link to post
Share on other sites
Ok, thanks ... works nice. But, is there anyway to keep (0,0) at the center of the screen and preserve the y-axis being positive as it goes up?

Share this post

Link to post
Share on other sites
Well the first 4 numbers entered into glOrtho are Left, Right, Bottom , Top.

So to get negative and positive y axis try
glOrtho(-200, 200, -200, 200, -1, 1);

That should place 0,0 in the center and both the x and y axis should go from -200 to +200.

Is that what you want?

"To err is human, to really mess up requires a computer"

Share this post

Link to post
Share on other sites

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

GameDev.net is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!