Search found 56 matches

by hobold
Wed Sep 27, 2017 1:58 am
Forum: General Development
Topic: Quick Question
Replies: 12
Views: 2226

Re: Quick Question

The relative speed of floating point square root computations has improved a lot since FPU hardware was first integrated into processor cores. Nowadays, if you can tolerate the occasional imprecision in the least one or two mantissa bits, single precision floating point square roots are fully pipeli...
by hobold
Fri Feb 03, 2017 5:02 am
Forum: General Development
Topic: Intersection of ray with quadric surface for hobby ray tracer
Replies: 6
Views: 3045

Re: Intersection of ray with quadric surface for hobby ray tracer

asyrov wrote:My next challenge is solid constructions.

My code above is not a good reference for constructive solid geometry. It does have a rather inefficient implementation; but that would only make sense in conjunction with spatial subdivision (where the voxels contained only pruned CSG subtrees).
by hobold
Sun Jan 29, 2017 4:20 pm
Forum: General Development
Topic: Intersection of ray with quadric surface for hobby ray tracer
Replies: 6
Views: 3045

Re: Intersection of ray with quadric surface for hobby ray tracer

The explanation behind general quadrics is not so simple and obvious. It does get quite tedious doing the math with 10 quadric coefficients and 12 more coefficients of a general affine transform. If you feel like digging through the source code of another toy raytracer, I can offer an older experime...
by hobold
Tue Mar 03, 2015 4:22 pm
Forum: General Development
Topic: Generalizing the Golden Ratio Sequence to Higher Dimensions
Replies: 4
Views: 3144

Re: Generalizing the Golden Ratio Sequence to Higher Dimensi

I gave golden ratio sampling along a Z-curve a try. It does cover the unit square nicely, but the sample spacing is less regular than true 2D low discrepancy sequences. I suspect that is due to the discontinuities of the Z-curve; the example images with the Hilbert curve looked a bit better in that ...
by hobold
Sat Feb 21, 2015 10:10 pm
Forum: General Development
Topic: Generalizing the Golden Ratio Sequence to Higher Dimensions
Replies: 4
Views: 3144

Re: Generalizing the Golden Ratio Sequence to Higher Dimensi

I cannot back this up with a citation or even only with plausible reasoning. But my first experiment would be bit interleaving, i.e. Z-order, also known as Morton code. In other words, instead of the Hilbert-Curve, I'd try a cheaper mapping from the unit interval to the unit square. I feel that the ...
by hobold
Tue Dec 23, 2014 12:32 pm
Forum: General Development
Topic: Quadrics kinda sorta work for real time
Replies: 34
Views: 16417

Re: Quadrics kinda sorta work for real time

With absolutely no pride whatsoever, I hereby announce the release of source code. There isn't much in it for you, dear readers, but if you want to see for yourself, surf to http://www.vectorizer.org/boar/index.html and scroll down a bit to the blog section. There you will find a tarball and a few s...
by hobold
Sat Aug 09, 2014 9:53 am
Forum: General Development
Topic: raytracing bezier patches..
Replies: 5
Views: 4192

Re: raytracing bezier patches..

Pardon the late reply. Finally got around to doing an illustration of surface smoothness, showing the range from piecewise constant to twice continuously differentiable. Lighting and texturing also have strong effects on perceived smoothness that are being shown. If you are interested see: http://ve...
by hobold
Fri Mar 07, 2014 10:53 am
Forum: General Development
Topic: Intel vs Nvidia
Replies: 3
Views: 2125

Re: Intel vs Nvidia

Both processor types will continue to converge somewhat. CPUs will continue to evolve more powerful SIMD ALUs (though not necessarily wider ones), and GPUs will further improve in terms of ALU utilization for a larger set of less regular algorithms. They will never ever meet in a single point, becau...
by hobold
Tue Dec 03, 2013 10:29 pm
Forum: Considered Harmfull
Topic: 64 core cpu from intel
Replies: 13
Views: 11359

Re: 64 core cpu from intel

Latest details about Knights Landing as reported by c't magazin: The modified cores have two parallel SIMD FPUs; theoretical peak throughput is two 512 bit wide fused multiply adds per clock, that means 64 single precision FLOPs or 32 double precision FLOPs per clock cycle. The issue width is still ...
by hobold
Mon Nov 25, 2013 11:38 am
Forum: Considered Harmfull
Topic: 64 core cpu from intel
Replies: 13
Views: 11359

Re: 64 core cpu from intel

Some more information has cropped up: http://vr-zone.com/articles/xeon-phi-knights-series-continues-landing-2015/64112.html Apparently Knights Landing will use a derivative of the Silvermont (Atom) core. The above report speaks about "two 512b vector units per core", but it is still unclea...

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