3D Code Help

[SNIPERDUDE]

Ok, so I have the basics of 3D. I think it's right...
Anyways I have hit another snag, how do I make it so I can fill in
faces or make it so some lines are hidden (when behind another face)?

Here's what I have so far:

Turing:

View.Set ("graphics") View.Set ("offscreenonly") colorback (120) const depth := 10 fcn divi (x, y : real) : real     if y = 0 then         result 9999999     else         result (x / y)     end if end divi proc drawdot3d (x, y, z : real, c : int)     drawdot (round (divi (x, z / depth) + maxx / 2) - 1, round (divi (y, z / depth) + maxy / 2) - 1, c) end drawdot3d proc drawline3d (x1, y1, z1, x2, y2, z2 : real, c : int)     drawline (round (divi (x1, z1 / depth) + maxx / 2), round (divi (y1, z1 / depth) + maxy / 2), round (divi (x2, z2 / depth) + maxx / 2), round (divi (y2, z2 / depth) + maxy / 2), c) end drawline3d var h : real := -10 var xe : int := 100 var ye : int := 100 var w : int := 50 var key : array char of boolean type Vert :     record         X, Y : int         Z : real     end record     type LineProp :     record         P1, P2, Clr : int     end record var Point : array 1 .. 100 of Vert var Line : array 1 .. 100 of LineProp for i : 1 .. 100     Point(i).X := 0     Point(i).Y := 0     Point(i).Z := 0     Line(i).P1 := 0     Line(i).P2 := 0 end for %% House Properties Point(1).X := 0 Point(1).Y := 0 Point(1).Z := 0 Point(2).X := 0 Point(2).Y := 50 Point(2).Z := 0 Point(3).X := 50 Point(3).Y := 50 Point(3).Z := 0 Point(4).X := 50 Point(4).Y := 0 Point(4).Z := 0 Point(5).X := 0 Point(5).Y := 0 Point(5).Z := 1 Point(6).X := 0 Point(6).Y := 50 Point(6).Z := 1 Point(7).X := 50 Point(7).Y := 50 Point(7).Z := 1 Point(8).X := 50 Point(8).Y := 0 Point(8).Z := 1 Point(9).X := 25 Point(9).Y := 0 Point(9).Z := 1.2 Point(10).X := 25 Point(10).Y := 50 Point(10).Z := 1.2 Point(11).X := 0 Point(11).Y := 30 Point(11).Z := 0.5 Point(12).X := 0 Point(12).Y := 20 Point(12).Z := 0.5 Point(13).X := 0 Point(13).Y := 30 Point(13).Z := 0 Point(14).X := 0 Point(14).Y := 20 Point(14).Z := 0 Line(1).P1 := 1 Line(1).P2 := 4 Line(1).Clr := 0 Line(2).P1 := 1 Line(2).P2 := 2 Line(2).Clr := 0 Line(3).P1 := 2 Line(3).P2 := 3 Line(3).Clr := 0 Line(4).P1 := 3 Line(4).P2 := 4 Line(4).Clr := 0 Line(5).P1 := 5 Line(5).P2 := 6 Line(5).Clr := 0 Line(6).P1 := 6 Line(6).P2 := 10 Line(6).Clr := 0 Line(7).P1 := 10 Line(7).P2 := 7 Line(7).Clr := 0 Line(8).P1 := 7 Line(8).P2 := 8 Line(8).Clr := 0 Line(9).P1 := 8 Line(9).P2 := 9 Line(9).Clr := 0 Line(10).P1 := 9 Line(10).P2 := 5 Line(10).Clr := 0 Line(11).P1 := 9 Line(11).P2 := 10 Line(11).Clr := 0 Line(12).P1 := 1 Line(12).P2 := 5 Line(12).Clr := 0 Line(13).P1 := 2 Line(13).P2 := 6 Line(13).Clr := 0 Line(14).P1 := 3 Line(14).P2 := 7 Line(14).Clr := 0 Line(15).P1 := 4 Line(15).P2 := 8 Line(15).Clr := 0 Line(16).P1 := 11 Line(16).P2 := 12 Line(16).Clr := brightred Line(17).P1 := 12 Line(17).P2 := 14 Line(17).Clr := brightred Line(18).P1 := 13 Line(18).P2 := 11 Line(18).Clr := brightred proc draw (xe : int) for i : 1 .. 100     if Line(i).P1 = 0 and Line(i).P2 = 0 then         exit     else         drawline3d (xe + Point(Line(i).P1).X, ye + Point(Line(i).P1).Y, h + Point(Line(i).P1).Z, xe + Point(Line(i).P2).X, ye + Point(Line(i).P2).Y, h + Point(Line(i).P2).Z, Line(i).Clr)     end if end for end draw loop     Input.KeyDown (key)         if key (KEY_UP_ARROW) then         ye += 3     elsif key (KEY_DOWN_ARROW) then         ye -= 3     end if         if key (KEY_RIGHT_ARROW) then         xe += 3     elsif key (KEY_LEFT_ARROW) then         xe -= 3     end if         if key ('w') then         h += 0.1     elsif key ('s') then         h -= 0.1     end if         drawfillbox (0, 0, maxx, maxy, 7)     draw (xe)     View.Update     delay(10)     exit when key (KEY_ESC) end loop

Use the arrow keys to move the house around, the 'W' key to zoom in, and the 'S' key to zoom out.

[Clayton]

10 million isn't exactly a very good estimate of x/0, I suggest you go with something bigger, like maxint.

[Zren]

Your either looking for:

Back-Face Culling: Ignore drawing the polygons that aren't seen.
http://www.gamedev.net/reference/articles/article1088.asp


Painter's Algorithm: Set each polygon to a certain depth, sort that list, then draw each polygon. The Java link is to the basic list generation, you get many errors with that much with polygons that cover each other. So there are some imperfect tests to run in order to slightly fix things.
http://www.javaworld.com/javaworld/jw-07-1997/jw-07-howto.html?page=1

http://www.siggraph.org/education/materials/HyperGraph/scanline/visibility/painter.htm

Personally I haven't done either before. I tried working with the Painter's algorithm once though. It kinda failed which is why Virus was old-school vector display styled.
Zylum's 3D Engine has both of these in it and is good to look at in order to understand concepts.
http://compsci.ca/v3/viewtopic.php?t=9639

[SNIPERDUDE]

Thanks guys, no time to look at it now...
I'll let you know how it goes when I have the time to look at it...

[CodeMonkey2000]

I think that using the z-buffer algorithm might be easier and the most correct, but since you can't use a graphics accelerator it will be VERY slow.

Striahgt from gamedev:

code:

Clear Z-Buffer to a certain value For every polygon     For every scanline of that polygon         For every pixel             If this is nearest pixel {                 Write Pixel                 Write Z into zbuffer             }         End     End End

[SNIPERDUDE]

Thought about that one.
Would it run at any good speed in C++?

[CodeMonkey2000]

Well if you are using openGL, it does it itself, just enable GL_DEPTH_TEST and make sure you clear the depth buffer. OpenGL can do it faster too since it uses hardware acceleration, you don't need to use the painter's algorithm in openGL, since it's not that much faster anyway.

[SNIPERDUDE]

Meh, first I'll think I'll try learning the painter's algorithm before I try learning other languages...