New raytracer - raytrace.c

[IanSeyler]

I've replaced gavare.c from the default demos that are installed. While it worked well I wasn't able to figure out how to make it run in parallel. I think it was due to all of the global variables being modified during runtime. I found another ray tracer written by Andrew Kensler and was able to get it running on BareMetal. I was also able to get it running in parallel! Each available core will render a line until the image is finished.

https://github.com/ReturnInfinity/BareMetal-Demo/blob/master/src/raytrace.c

Note the lines at the bottom of the image as each core renders a line. This was on the 4-core VirtualBox system

I've also tested this on a 6-core physical system.

gavare.c will remain in BareMetal-Demo for reference.

[WEREMSOFT]

if I set the virtual machine to have 8 cores I have this

[WEREMSOFT]

If I try to render a 320 x 200 image, this is what I have

Changed lines 28 and 29 and commented lines 220 and 221

[WEREMSOFT]

Glitches aside. It’s amazing to have this demo since shows how to use multi threaded code on the os. Great job!

[IanSeyler]

if I set the virtual machine to have 8 cores I have this

I've fixed this in the latest version. Multiple cores were getting the same value for y. A SMP_LOCK/SMP_UNLOCK fixed that.

Here is QEMU with 32 cores:

[IanSeyler]

If I try to render a 320 x 200 image, this is what I have Changed lines 28 and 29 and commented lines 220 and 221

That would be expected as the physical screen dimensions are still 1024x768. This would need to be adjusted as well:

int offset = (y * X + x) * 4; // Calculate the offset into video memory for this line

[IanSeyler]

Glitches aside. It’s amazing to have this demo since shows how to use multi threaded code on the os. Great job!

Thanks!!