OpenGL immediate mode in window coordinates

Asked Apr 05 '16 at 19:03

Active Apr 05 '16 at 20:08

Viewed 56 times

As the title says, I'm trying to draw stuff in immediate mode in window coordinates - which is probably the wrong term. That is, the coordinate system that has its origin in the top left corner of the window, with its Y axis expanding downwards the height of the window, and its X axis expanding sidewards along the width. I want to be able to draw a line from the top-left corner to the bottom-right corner like this:

glColor3ub(255, 255, 255);
glBegin(GL_LINES);
  glVertex2f(0.0f, 0.0f);
  glVertex2f(1280.0f, 720.0f);
glEnd();

Yes, I am aware that immediate mode is deprecated, but please answer within old OpenGL's context. How do I need to set up OpenGL's matrix stack so I can draw in window coordinates, like seen above? Thanks in advance!

edited Apr 05 '16 at 20:08

asked Apr 05 '16 at 19:03

tubberd

1

`GL_LINE` won't work with `glBegin()`, you need `GL_LINES`. Yay type-less "enums". – genpfault Apr 05 '16 at 19:50
In short glOrtho is your solution. – Andreas Apr 05 '16 at 20:03
`glMatrixMode( GL_PROJECTION ); glLoadIdentity(); glOrtho( 0.0, 1280.0, 720.0, 0.0, -1.0, 1.0 ); glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); drawStuff();` – genpfault Apr 05 '16 at 20:09
@genpfault oops, sorry didn't think this question already had an answer. Sorry about that. And yea, i always confuse things like that. – tubberd Apr 05 '16 at 20:09
@calcyss: Eh, no worries, good luck with your future OpenGL-ing! – genpfault Apr 05 '16 at 20:14

OpenGL immediate mode in window coordinates

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