Please critique my idea for plotting a point in 3D space on a 2D screen

Utwo · 2004-01-13T03:31:00

Ok ok ok. I don''t have a lot of programming experience but I think this might work. I drew visuals too. Really this is all for my own benefit because until I put my ideas down on "paper" but I figured I''d have others take a look as well because frankly I don''t know if I''m even close to being right. I want to be able to define a point in 3D space with x, y, and z coordinates, and then plot it on a 2D screen. I think I have this figured out. Please let me know if I''ve got this wrong. Ok, first, I understand that the cone of vision for the uman eye is 60 degrees. I don''t suppose it really matters what I use for the 3D "camera" though, but I''ll go with 60 degrees just for the hell of it: Alright. First thing I should mention is that the x, y, and z coordinates will be relative to the camera''s point of view. Later if I program any games with this (I have one in mind but I doubt I will finish it, because I never do), I will probably have all the points'' coordinates relative to the game world, and then convert the [i">visible[/i"> points in each from to be relative to the camera to make calculations easier. But for now, I have the field of view devided into 4 quadrantS: Now suppose I plot a point in that field of view: It''s 7 "units" on the z axis away from the camera, 2 units on the x axis to the right, and 2 units high on the y axis. Here''s another visual so you can see what I mean: Now the basic idea here is that I want to know what angles (x and y) exist from the center of the point of view and then determine what percentage of the total 60-degree cone these angles take up. Here''s what I mean: Now here''s a better picture with the useless stuff removed: Knowing that the point is both 7 units away and 2 units high, I can easily figure out that the angle here is 15.9454 degrees. The other angle is also 15.9454 degrees because it has the same measurements, so no need to do the math again this time. This tells me that the 15.9454-degree angle is 26.5756% of the total 60-degree cone. When I apply that percentage to the vertical and horizontal resolution of the display, I find that it equals about 64 and 85 pixels. I have to round because duh you can light a fraction of a pixel. Anyway, so now I know how many pixels away from the center of the screen the point should be, right? And now the finished point: The one thing I did notice that was wrong while typing this is that the cone should probably be 60 degrees wide and 45 degrees tall, since the screen has a 4:3 aspect ratio. This method will probably make everything look a little smooshed. Other than that though it seems it should work. What do you think?

For Beginners

Started by Utwo January 04, 2004 08:31 PM

70 comments, last by Utwo 20 years, 3 months ago

jtmerchant

126

January 12, 2004 12:02 AM

NOTE: I''VE ONLY READ THE FIRST AND A HALF PAGES OF REVIEWS.
Utwo: You don''t know much about programming, I don''t know much about trig! We''d make a nice team! Hehe JK. I work alone and I bet you do to. Don''t make a reply on that... maybe I should just backspace that out... Anyway! I must say good job. Even though you may be "reinventing the wheel", I''d say go ahead and try to implement it. I mean think about it. You''ll get some joy out of creating something like this. Now I''m not saying to make all of your programs using this, but I suggest making a few, and submitting this and them to the article section. Just remember that if you do decide to do something serious, go learn DirectX because if you try to implement a tenth of what they do in Direct3D by yourself with absolutely no help from any friends or co-workers, you won''t get very far in a human life span. Not to be negative, as I encourage you to do some stuff with this, as this is nice stuff.

Ogre (from Warcraft 3): Me dink dis shud be make stiky.
Other Head: Me dink dis shud be make un-stinky.
First Head: Sorry.

Utwo

100

Author

January 13, 2004 03:31 AM

Excellent. It works.

I''m peeing my pants here.

---signature---" Actually, at the time, I didn't give a damn about the FoxNews issue... just that you would come swooping in with your Super Mith cape flapping behind you and debunk it just because it didn't happen in your living room." - InnocuousFox

Please critique my idea for plotting a point in 3D space on a 2D screen

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Please critique my idea for plotting a point in 3D space on a 2D screen

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