Re: spinning "E" demo questions, for ray casting & surface rendering
- Posted by DanM May 19, 2009
- 1078 views
Look at this image
http://imgbin.org/index.php?page=image&id=521
Upper image is the user looking to the computer screen.
Lower is your virtual camera in your virtual world. The image is projected on a virtual screen. The position of the screen is between the camera and the object.
From this point of view, the coordinate of the user is the same coordinate of the camera.
My proposal is to check each point on the virtual screen (each point on your real screen or window), project a line from camera to this point and continue the same line to check if collides any polygon of the object.
Thank you so much for taking the time to draw me a picture!
So, the POSITION of the viewer is the same as the POSITION of the camera, and that makes the COORDINATES of the camera(necessary to assert the beginning of the line to project into the screen for ray casting?), x = 0, y=0, and z = 0 ? In other words, at the origin of the virtual space?
The reason I keep asking about the actual coordinates of the virtual camera is that I'm looking at the Euphoria demo of a spinning "E", and it's somewhat difficult to figure what the camera coordinates for that are. And to do any ray casting, it would seem that I need those coordinates. I don't think they are 0,0,0, at least not in that space/scene. I realize that the position of the camera can depend on what the app programmer decides, I'm just trying to start with the spinning "E" 'cause it's there (and has what are probably pretty powerful conversion/translation/rotation functions, given that Rob wrote them?).
And again, thanks for drawing me a picture!
Dan
