opengl origin....

[qawded]

i am very new to opengl ...please let me know where is the origin of opengl window....
and by default is it orthographic projection??

[tonyo_au]

The matrices both default to the identify matrix which makes the projection orthogonal. It is unusual to leave these un-modified except for a simple test.
Since you posted this in the shader section I should add that for a shader there are no defaults you muse supply your own matrices.

[qawded]

The matrices both default to the identify matrix which makes the projection orthogonal. It is unusual to leave these un-modified except for a simple test.
Since you posted this in the shader section I should add that for a shader there are no defaults you muse supply your own matrices.

sorry but i could not undestand much...i wanted to ask whether the origin is bottom left corner or otherwise...

Thanx

[tonyo_au]

The origin is the centre of the viewport but you have to set the viewport - usually to the whole window. The viewport will be 2 world units wide and high for -1 - +1

[qawded]

The origin is the centre of the viewport but you have to set the viewport - usually to the whole window. The viewport will be 2 world units wide and high for -1 - +1

thanx a lot....but how can i set the full window as my viewport.....and if i can set a portion of it ...is there a way to mark it,,i mean sum solid boundary....i know my questions are very basic,,,,,but pls help..your help is highly obliged....

[Aleksandar]

I guess you should read this first.