Making a 3D (viewport-ish)/real-time renderer.. from skratch

zsouthboy · Post by **zsouthboy** » Tue May 01, 2007 11:51 am

Holy shit man!

Nice job!

Now hurry up and kick Indigo's ass, and we'll all be using Arnego in no time at all

zsouthboy · Post by **zsouthboy** » Tue May 01, 2007 2:44 pm

arne, you've inspired me to try my hand at actually implementing a rasterizer too.

Here's a link to how far I got today: http://www.zsouthboy.com/lame.zip

Almost have a coherent triangle!

(The extra lines are fun, eh? Wee!)

Such a great brain exercise though - having to remember trig functions that i don't get to use in every day life!

First thing I'm doing when I get to rasterizing multiple triangles (correctly) is finding a way to write to a buffer, that is memcpy'd to the screen - it's farkin slow to write line by line.

CTZn · Post by **CTZn** » Tue May 01, 2007 3:47 pm

Hehe, nice Arne !

Er, I'm counting 8 tris, is that me ?

Kram1032 · Post by **Kram1032** » Tue May 01, 2007 9:10 pm

lollish raserizer, zsouthboy!
yup funny lines

arneoog · Post by **arneoog** » Tue May 01, 2007 10:39 pm

I just woke up just now and knew exactly what I had to do to make it z-buffer the image!

So I fixed this in five minutes after I got out of bed,
and now it's working!!!
WOOHEE!!!

>>Working Z-Buffer<<

zsouthboy/Chris, I couldn't run you "Lame" renderer..

Cool name on a renderer

I don't think I can even think of kicking indigo's ass yet

Kram1032 · Post by **Kram1032** » Tue May 01, 2007 10:45 pm

!!!

what are those splitted edges?

Btw: what ever you did: I don't need to rewrite the link anymore, now

It works directly!!

zsouthboy · Post by **zsouthboy** » Wed May 02, 2007 12:14 am

You need .net 2.0 installed, to run my crappy crap crap.

Awesome that you got z buffering up and running.

What is next? I suggest working on the aliasing between tris (in the large box).

arneoog · Post by **arneoog** » Wed May 02, 2007 4:03 am

WoooHoooooo!!!

I got colors and selection to work!!!

http://roxworth.elqx.com/obj_viewer/?s= ... =cubeSmall

EDIT:
New Url variables:
- &selected= (model name)
- &wire= (1)
- &hide= (model name)

Kram1032 · Post by **Kram1032** » Wed May 02, 2007 4:26 am

looks great, already!
the edges still are splitted :S

arneoog · Post by **arneoog** » Sun May 13, 2007 11:10 pm

Questions:
How can I find the current depth on a triangle for any given point?
Having big problems finding a way to do it..

..right now it's just taking the mid depth of each tri..

And, any idea why there is gaps between each tri?

example

Thanks!

Kram1032 · Post by **Kram1032** » Sun May 13, 2007 11:14 pm

maybe, your float isn't accurate enough???

two last problems, before it can called somehow a 3D-renderer :S

arneoog · Post by **arneoog** » Wed May 16, 2007 5:18 pm

Yeah you're probably right, Mark..
I'll try to fix this later..

But does no one know how to do per pixel Z-Buffering?

I really want to get this working, and make it C++

...

zsouthboy · Post by **zsouthboy** » Wed May 16, 2007 11:52 pm

Two things:

1) For any given point you're shading in a tri, to find the distance from camera, simply interpolate the z value of each vertex to that pixel. Same equation as the scanline rasterization!

2) Gaps between the tris are result of subpixel inaccuracy. All modern renderers (OGL & D3D) take care of this problem by shading a pixel :: the TOP LEFT POINT of it is inside the tri.

Check http://www.devmaster.net/articles/softw ... /part4.php

arneoog · Post by **arneoog** » Fri May 18, 2007 11:13 am

ah, okay

Thanks, zsouthboy (again

)

New question:

I can't find any info/tutorial on how to write a .bmp file using only basic C++..
I have an example of it, but it's in such a complex code that I can't figur out how it actually work

Would be very nice if someone knew a page with all info regarding this,
or could post/send a very simple example of how to do it..

Btw, I have transformation, projection and triangle filling working in C++ now

..but only printing the result as characters.. *hint hint* hehe

Cheers!

zsouthboy · Post by **zsouthboy** » Fri May 18, 2007 11:30 am

.BMP files!

Yay!

Something I know!

I'll find my notes, but I wrote something to generate graphs in ASP a while back, and it out put 24-bit BMP files. I didnt' deal with any compression BS

I'll have to find the list I have in mind, it was basically byte offsets (where to write what values).