Voxel Rendering (Beginner)

Hi,

Im trying to build a voxel renderer, however im going to need some help as I am a total beginner to this.

Im going to use the ray casting technique, and im going to cast through every pixel on my view plane. My question is given my 3D Array of pixel values (R,G,B) how do I cast the ray and find which voxel (element in 3d array) the ray hits?

Many Thanks
-Alex

Something like this? (And following pages.) http://www.permadi.com/tutorial/raycast/rayc4.html

Yes, something like that.

However, that takes shortcuts and uses strips and other optimizations that I don't want. I ideally want it to cast through every pixel on the view plane and calculate the colour of that pixel based on the intercept of the ray and an actual voxel.

Sorry If Im not making any sense, im really new to this

Cheers
-Alex

So . . . you want a ray that passes through every pixel in your 3D space? What do you mean?

BTW, I probably shouldn't be helping you with this, I'm newer than you are. :)

Quote:

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Originally Posted by dwks

So . . . you want a ray that passes through every pixel in your 3D space? What do you mean?

BTW, I probably shouldn't be helping you with this, I'm newer than you are. :)

---

No.

There is a view Plane (The eventual image you see). You shoot a ray from a constant point through each pixel on the view plane. Follow the ray through until it hits the closest voxel in its path.

I just don't know how to find the intercept of the ray and voxel mathematically/programming.

Cheers
-Alex

I really have no idea. The only thing I can suggest is to keep looking. Perhaps the tutorial I posted has the answer to your question later on, such as here: http://www.permadi.com/tutorial/raycast/rayc7.html

Quote:

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Originally Posted by dwks

I really have no idea. The only thing I can suggest is to keep looking. Perhaps the tutorial I posted has the answer to your question later on, such as here: http://www.permadi.com/tutorial/raycast/rayc7.html

---

Yeah,

Had a look through it. Not really what I wanted, it seems to cut many corners to get a good frame rate.

All I want really is an algorithm (simple not optimised) to calculate the closest voxel intersection along a ray.

Cheers
-Alex

How about this hit from here?

The basic algorithm looks pretty simple.

Code:

---

loop {
    if(tMaxX < tMaxY) {
        tMaxX= tMaxX + tDeltaX;
        X= X + stepX;
    }
    else {
        tMaxY= tMaxY + tDeltaY;
        Y= Y + stepY;
    }
    NextVoxel(X,Y);
}

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It probably glosses over a lot of details, though.

Ken Silverman released the source code to his voxel library if you want to check it out. His coding tends to be messy though.

http://www.advsys.net/ken/voxlap/voxlap05.htm

If you are casting a ray from the viewer through every pixel on the screen you are not doing voxel rendering, you are doing ray tracing.

Voxel rendering is an approximation using volumes and does not require that you ray-cast the entire screen. There are several methods of rendering voxels but the ray-casting method is more suited to terrain than it is 3D objects.

Quote:

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Originally Posted by Bubba

If you are casting a ray from the viewer through every pixel on the screen you are not doing voxel rendering, you are doing ray tracing.

Voxel rendering is an approximation using volumes and does not require that you ray-cast the entire screen. There are several methods of rendering voxels but the ray-casting method is more suited to terrain than it is 3D objects.

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Ok i only got the ray casting idea from a voxel terrain tutorial. Could you please explain further the proper technique?

Thanks
-Alex

In one post? Hehe. No way.

Google it.