View Full Version : questions about screen, planes and viewpoint ...

08-28-2001, 04:35 AM
i have some questions :
-can someone tell me where i can found all opengl matrices (projection,viewport, ...)
-i have also a problem : i rotate the camera with gluLookAt, before tranfos the viewpoint isV= (0,0,-50) then i apply
transfo to this point to obtain the transformed viewpoint (but multiply by the matrix M) which i put in glulookat, but
when i draw the line (0,0,0) M*V nothing appears or not in the center of my screen, why ?
-someone also know how to calculate the distance between the screen and the viewpoint ?
-is the screen perpendicular to the line (viewpoint,point which is viewed [2nd parameter in glulookat]) ?
that's all for the moment ! thnx for your answers

08-28-2001, 03:05 PM
A/ glGetFloatf( GL_PROJECTION_MATRIX , mat ); etc

C/ they are the same
D/ yes they are at right angles

check the red book out for a lot of info also seacrh the web for linear algebra explanations