View Full Version : Trouble with converting to openGL coordinate syst.
03-29-2009, 01:37 PM
Hi, i have a robot that uses a different coordinate system than openGL does and i have great difficulties in converting this to the openGL coordinate system. I like to draw some static elements (which use the robot coordinates) into openGL. The robot coordinate system has +Z pointing upwards, +Y pointing to the left, +X pointing backwards. Help is appreciated with this problem.
Well, simply swap / negate the coordinates from your robot, before you put them into gl.
The transformation should look like this:
(x, y, z) -> (-y, z, x)
It would be easiest to write a little helper function, to do this:
vec3 MakeGLCoord (vec3 v)
return (vec3 (-v.y, v.z, v.x));
Then you can render your stuff like this:
vec3 vRobotPos = ...
vec3 glPos = MakeGLCoord (vRobotPos);
glVertex3f (glPos.x, glPos.y, glPos.z);
Hope that helps you. Though i do not guarantee that i got the transformation correct ;)
03-29-2009, 10:01 PM
the OpenGL coordinate system is a right-hand system with
x pointing right
y pointing upward
z pointing toward you ( out of the screen )
so the coordinates form yours to OpenGL
x ( 1, 0, 0 ) -> x' ( 0, 0, -1 )
y ( 0, 1, 0 ) -> y' ( -1, 0, 0 )
z ( 0, 0, 1 ) -> z' ( 0, 1, 0 )
just like Jan have said
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