Render 3d object with screen coordinates

kobingo · 2005-06-23T02:11:50

Hey! I wish to render my 3d objects with untransformed vertices, but be able to give the renderfunction x, y screen coordinates, and then somehow recalculate where in the world to draw the object. I don't want to care about the camera position. I have tried to use the picking method, but it seems it doesn't really work with what i'm trying to achive. I would like to have a function RenderObject(int x, int y) - and then have the object drawn exactly at that position on my screen. Can anyone give a helping hand? Thanks in advance! /Jens

Graphics and GPU Programming Programming

Started by kobingo June 17, 2005 03:54 AM

21 comments, last by kobingo 18 years, 10 months ago

kobingo

175

Author

June 22, 2005 02:25 AM

Well, now I got it to almost work, just as before. But the Z value make a difference if i do this:

Vector3 Vec1 = new Vector3(0,0,1);Vector3 Vec2 = new Vector3(1,0,1);Vector3 Vec3 = new Vector3(0,1,1);Plane P = Plane.FromPoints(Vec1, Vec2, Vec3);

or this:

Vector3 Vec1 = new Vector3(0,0,3);Vector3 Vec2 = new Vector3(1,0,3);Vector3 Vec3 = new Vector3(0,1,3);Plane P = Plane.FromPoints(Vec1, Vec2, Vec3);

I get differnet x,y,z values when calling:

Vector3 World = Plane.IntersectLine(P, NearVec, FarVec);

depending at which Z value I create my plane with.

-------Ladybird Galaxy Game Ladybird Galaxy Blog Shmup Development (with XNA and C#)

Endurion

5,545

June 22, 2005 09:03 AM

Well, that does make sense. The x,y vary if the x,y screen pos is not exactly in the center. Imagine the rays going from a point like a star burst. The farther the z value the more x and y are moving towards the frustum border
(if you've got perspective on that is).

Fruny: Ftagn! Ia! Ia! std::time_put_byname! Mglui naflftagn std::codecvt eY'ha-nthlei!,char,mbstate_t>

kobingo

175

Author

June 23, 2005 02:11 AM

Have to figure out a way to do it... Thanks for all your help :-)

-------Ladybird Galaxy Game Ladybird Galaxy Blog Shmup Development (with XNA and C#)

Render 3d object with screen coordinates

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