🔒 Locked

OpenGL Problems

Started by Mad_Koder Jul 29, 2006 at 1:23 PM 3 replies 750+ views

Original Post

Jul 29, 2006 at 1:23 PM

I am haveing problems with a Wiggle app , the window isn't exactly the size i declare it to be, I cant figure out how to know where points will be based on glTriangles(): pixels per unit (which is verry annopying, for i cant draw polygons). I cant rerember all these terms for the different pipeline for modelview, and I dont understand how glPush(); and glPop(); work. Can someone explain this stuff I am verry confused.

Brother Bob

Mod

218

Brother Bob

Jul 29, 2006 at 1:33 PM

If you're using Windows, then keep in mind that the size passed to CreateWindow is the size of the window, not the client area inside the window. Either adjust the window size with AdjustWindowRect or catch the WM_SIZE message for the actual size. If you're using a third party library, check the documentation for size callbacks or query functions.

Mad_Koder

Author

Mad_Koder

Jul 29, 2006 at 1:54 PM

thanks, but what about the coordinate system , I cant figure out how many units is a pixel to get primitives exact , how do I do so. I used to know but I'm brain dead at the moment.

hplus0603

Mod

3,014

hplus0603

Jul 29, 2006 at 2:15 PM

To get 1:1 mapping, you have to first get the size of the viewport, which you'll get through the windowing system (typically, using GetClientRect()).

Then, set glOrtho() to that size window, and you have a 1:1 relation between coordinates and pixels.

Ezbez

154

Ezbez

Jul 29, 2006 at 2:21 PM

An example call to glOrto():

glOrtho(0,SCREEN_WIDTH,0,SCREEN_HEIGHT,0,1);

Will make it a 1:1 ratio, like hplus said.

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.