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Rotation problem

Started by int01h Jul 2, 2006 at 5:23 PM 3 replies 850+ views

Original Post

Jul 2, 2006 at 5:23 PM

Hi guys.. got a question. My Player is at: player.x=10; player.z=10; the tree is at: tree.x=34; tree.z=33; i would like to call glRotatef(...) before rendering player to let him face the tree with his eyes.. what calculation should i perform to rotate his face towards the tree ? Regards!

algumacoisaqualquer

Jul 2, 2006 at 5:55 PM

I would guess angle = atan2(tree.x - player.x, tree.z - player.z)
Well, since we are in a 2D plane, then glRotatef(angle, 0, 1, 0) - you may need to use -angle instead, I'm not really shure. I haven't tested this tought. To be honest, I wouldn't trust myself on that, but hey, I think it's quite simple to try it out.

int01h

Author

int01h

Jul 2, 2006 at 6:18 PM

float rotater=0;
rotater=atan2(TREE.x-PLAYER.x , TREE.z -PLAYER.z);
glRotatef(rotater,0,1,0);

Doesn't seem to be working, in fact player isnt rotated in ANY direction.. ;(

Zakwayda

1,120

Zakwayda

Jul 2, 2006 at 7:15 PM

Quote:
Original post by int01h
float rotater=0;
rotater=atan2(TREE.x-PLAYER.x , TREE.z -PLAYER.z);
glRotatef(rotater,0,1,0);

Doesn't seem to be working, in fact player isnt rotated in ANY direction.. ;(

C++ math library functions work with radians; OpenGL functions work with degrees. You will need to convert the angle to degrees before calling glRotatef().

int01h

Author

int01h

Jul 2, 2006 at 7:33 PM

It works after conversion

You rule guys!

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