https://github.com/cheind/volplay
Manipulating, rendering and interacting with volumetric data
https://github.com/cheind/volplay
Last synced: about 1 year ago
JSON representation
Manipulating, rendering and interacting with volumetric data
- Host: GitHub
- URL: https://github.com/cheind/volplay
- Owner: cheind
- Created: 2014-03-16T07:40:46.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2015-04-04T17:38:25.000Z (about 11 years ago)
- Last Synced: 2025-04-14T00:16:26.490Z (about 1 year ago)
- Language: C++
- Homepage:
- Size: 1.1 MB
- Stars: 6
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: Readme.md
Awesome Lists containing this project
README
# volplay
_volplay_ is a library for creating, manipulating and interacting with volumetric data. Focus of this library is clean, reference code. All computations carried out on CPU with minimal focus on parallelism.
## Creating and Manipulating Signed Distance Fields
A signed distance field in _volplay_ is represented by a hierarchy of `volplay::SDFNode`. Leaf nodes represent primitives such as spheres, boxes and planes. Intermediate nodes encapsulate functions on other nodes such as intersection, union, difference, repetition and transformation.
To start creating a signed distance field use `volplay::make()`.
```cpp
#include
namespace vp = volplay;
vp::SDFNodePtr u = vp::make()
.join()
.sphere().radius(0.5)
.transform().translate(vp::Vector(5, 0, 0))
.sphere().radius(0.2)
.end()
.end();
```
Here the `join()` member method creates a new `volplay::SDFUnion`. Its children are an `volplay::SDFSphere` node with radius 0.5 and a transformed `volplay::SDFSphere` with radius 0.2. The complete graph is shown below. The domain specific language chosen comes quite close to a natural language one would prefer to create hierarchies.
## Ray-tracing Signed Distance Fields
The namespace `volplay::rendering` provides methods to directly visualize the signed distance field by ray-tracing it. Besides the signed distance field itself, rendering can make use of material properties of individual nodes. The ray-tracing pipeline is implemented in `volplay::rendering::Renderer` and involves the following other entities:
- A scene `volplay::SDFNode` to be rendered. Each node can be attributed with materials `volplay::rendering::Material`
- A camera `volplay::rendering::Camera` defining the viewpoint and lens parameters.
- A set of lights `volplay::rendering::Lights`.
- A set of image generators `volplay::rendering::ImageGenerator` encapsulating the types of images to be generated.
The example [example_raytracer.cpp](examples/example_raytracer.cpp) demonstrates rendering of two spheres resting on a plane.
When executed the following set of images is generated. From left to right: Blinn-Phong shaded image with shadows and materials applied, depth image of scene and heat image of scene showing hotspots of raytracing.
## Surface Reconstruction from Signed Distance Fields
The namespace `volplay::surface` provides methods to explicitly generate a polygonal mesh from an iso-surface in a signed distance field. Currently an implementation of Dual Contouring `volplay::surface::DualContouring` is available. Results can be exported in .OFF format. Here is an example
```cpp
#include
namespace vp = volplay;
namespace vps = volplay::surface;
vp::SDFNodePtr scene = vp::make()
.difference()
.join()
.sphere().radius(1)
.transform().translate(vp::Vector(0.8f, 0.8f, 0.8f))
.sphere().radius(1)
.end()
.end()
.plane().normal(vp::Vector::UnitZ())
.end();
vps::DualContouring dc;
dc.setLowerBounds(vp::Vector(-2,-2,-2));
dc.setUpperBounds(vp::Vector(2,2,2));
dc.setResolution(vp::Vector::Constant(vp::S(0.05)));
vps::IndexedSurface surface = dc.compute(scene);
vps::OFFExport off;
off.exportSurface("surface.off", surface);
```
This produces the surface below. One of the big benefits of Dual Contouring is that it naturally preserves sharp features.
# References
http://aka-san.halcy.de/distance_fields_prefinal.pdf
http://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
http://www.ronaldperry.org/SIG2006Course_FriskenPerryDistFields.pdf
http://cg.ibds.kit.edu/downloads/IntModelingSDF.pdf
http://iquilezles.org/www/material/nvscene2008/rwwtt.pdf
http://elib.uni-stuttgart.de/opus/volltexte/2010/5229/pdf/DIP_2970.pdf
http://csokavar.hu/raytrace/imm6392.pdf
http://9bitscience.blogspot.co.at/2013/07/raymarching-distance-fields_14.html
http://www.arcsynthesis.org/gltut/Illumination/Tut12%20Monitors%20and%20Gamma.html
http://www.cambridgeincolour.com/tutorials/gamma-correction.htm