This sample code is in regards to a project that used OWL to evaluate the feasibility and performance of RTX-Accelerated ray tracing for Glyph-based data visualization.
Citation for the corresponding paper:
This project uses OWL, and should be checked out with owl as a
submodule. To do so, use the --recursive flag when cloning this
repository; alternatively, if you forgot this you can also pull the
submodules via
git submodule init
git submodule update
which should also end up fetching the correct version of OWL.
To build, you also need the typical OWL dependencies, ie, a C++ 11 compatible compiler, CUDA, and OptiX (version 7 or newer). Both windows and linux should be supported.
Using cmake, this project should build on both linux and windows. If you're not familiar with cmake, it is suggested to follow OWL's instructions to first build the samples that come with OWL, then repeat the same steps here.
The following files/classes implement the glyph types we presented in
the paper. FileName.h and FileName.cpp contain the OWL host code
and device/FileName.cu contain the respective OptiX 7 device programs.
This is an example of a non-affine glyph; i.e. the glyph cannot just be transformed with the instance transform, so the geometry is stored in extra buffers.
ArrowGlyphs.h ArrowGlyphs.cpp device/ArrowGlyphs.cu
Sphere glyphs are "affine glyphs", i.e. under transformation they can become general ellipsoids and that behavior is desired
SphereGlyphs.h SphereGlyphs.cpp device/SphereGlyphs.cu
This is a sphere glyph, but the geometry of the glyph is non-affine, and instead it is spread out and blurred over the extent defined by its instance bounds according to the link velocity and link acceleration
MotionSpheres.h MotionSpheres.cpp device/MotionSpheres.cu
This is a more involved glyph that uses a Newton/Rhaphson solver to compute ray/superquadric intersections. The glyph types implements a trick, as it doesn't use the bounding box or bounding sphere as an initial root estimate, but rather a coarse tessellation. The intersection with that tessellation is computed using hardware-accelerated ray/triangle intersections.
SuperGlyphs.h SuperGlyphs.cpp device/SuperGlyphs.cu
After building is complete, you should end up with an executable
./owlGlyphs or owlGlyphs.exe.
Using the test data set from the root dir of this repo just start with
./owlGlyphs testdata.glyphs.
| Arrow glyphs: cmdline: --arrows | -arr  |
Sphere glyphs: cmdline: --spheres | -sph  |
| Motion blur glyphs: cmdline: --motionblur | -mb  |
Super quadric glyphs: cmdline: --super | -spr  |
Keystrokes:
- ! : dump screenshot
- H : enable/disable heatmap
- </> : change heatmap scale up/down
- C : dump current camera
- +/- : change mouse motion speed
- I: enter 'inspect' mode
- F: enter 'fly' mode
Mouse:
- left button: rotate
- middle button: strafe
- right button: forward/backward
The owlGlyphs program can optionally load triangle models in wavefront obj
format (cmdline: -obj <file.obj>). For that we use
tinyobjloader which is
included as source code. Tinyobjloader's licence is
MIT
We use code for ray/quadric intersection testing by Inigo Quilez. Those tests can be found on shadertoy: ray/cylinder test, ray/rounded cone test. License is MIT