EasyPBR

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EasyPBR: A Lightweight Physically-Based Renderer
Radu Alexandru Rosu ¹, Sven Behnke ¹,
¹University of Bonn, Autonomous Intelligent Systems

EasyPBR is a lightweight Physically-Based Renderer designed for ease of use and fast prototyping. It abstracts away most of the complexity of rendering allowing the user to display high quality images in only a couple of lines of code. By default, EasyPBR tries to choose parameters in order to best render a particular scene but if more control is needed, the whole rendering process is controllable through either a Python script or C++ program. EasyPBR is written in C++ and OpenGL and provides Python bindings to most of it's functionality.

Usage

An example of a python3 script which shows a single mesh using the default viewing parameters:

try:
    import torch
except ImportError:
    pass
from easypbr  import *

config_file="./config/default_params.cfg"

view=Viewer.create(config_file)
lucy = Mesh("./data/lucy.obj")
Scene.show(lucy, "lucy")

while True:
    view.update()

Alternatively, one can also start an empty viewer and dragging and dropping meshes on it:

./python/empty.py

One can also define their own mesh by filling up the vertices and faces vector:

view=Viewer.create()   #a viewer with no argument reads by default the parameters from "./config/default_params.cfg"

mesh=Mesh()     #create an empty mesh
mesh.V=[        #fill up the vertices of the mesh as a matrix of Nx3
    [0,0,0],
    [0,1,0],
    [1,0,0],
    [1.5,1.5,-1]
]
mesh.F=[        #fill up the faces as a Nx3 matrix of integers which point into mesh.V
    [0,2,1],
    [1,2,3]
]
mesh.m_vis.m_show_wireframe=True

Scene.show(mesh,"mesh")
while True:
    view.update()

An example of using EasyPBR from an external C++ application can be seen in ./examples/example_cpp

Features

Deferred rendering
Physically-based shading
Screen Space Ambient Occlusion (SSAO)
Shadow Mapping with Percentage Closer Filtering for soft shadows
Image Based Lighting (IBL) using HDR maps
Eye Dome Lighting for point cloud rendering
Separable Subsurface Scattering for realistic skin shading
Various tonemapping operators (Rheinhard, Unreal, ACES)
Shader hotloading
Various modes of visualization (mesh, wireframe, point cloud, surfel)
Loading of multiple meshes formats (.obj, .ply, .pcd, .off)
Drag and drop of meshes and HDR maps directly in the viewer
Easy extension and usage from other packages

Install

Dependencies:

$ sudo apt-get install python3-pip python3-setuptools python3-numpy libglfw3-dev libboost-all-dev libeigen3-dev libpcl-dev libopencv-dev

Optional dependencies:

Allow for shader hotloading, so changes to .glsl files are automatically recompiled and used while the program is running:

$ sudo apt-get install libkqueue-dev

Build and install:

$ git clone --recursive https://github.com/RaduAlexandru/easy_pbr.git
$ cd easy_pbr
$ make

Troubleshoot:

If the GUI is too small or to big, enable the hidpi: true in the corresponding config file from easy_pbr/config.

The error libGL error: No matching fbConfigs or visuals found can be fixed with: export LIBGL_ALWAYS_INDIRECT=1

Examples

Various examples can be found in the ./examples folder. A short description of each one is given here. The various effects are achived through a combination of different .cfg file configurations and different setting established in the python file.

Name	Description
Deferred Physically based rendering	Real-time rendering of a scene with 'physically-based' materials (GGX BRDF introduced in Microfacet Models for Refraction through Rough Surfaces, Walter et al., 2007), using deferred rendering and an HDR pipeline with bloom and SSAO. Run with ./examples/pbr.py
Subsurface Scattering	Subsurface Scattering for skin rendering. Run with ./examples/subsurface_scattering.py Download head model from here
Shadows and Ambient Occlusion	Run with ./examples/shadows.py
Bloom	Run with ./examples/bloom.py
Cloud render	Eye-dome lighting and SSAO for shading

Citation

@inproceedings{rosu2021easypbr,
  title={EasyPBR: A Lightweight Physically-Based Renderer},
  author={Rosu, Radu Alexandru and Behnke, Sven},
  booktitle={Proc. of 16th International Conference on Computer Graphics Theory and Applications (GRAPP)},
  year={2021}
}

License

EasyPBR is provided under the terms of the MIT license (see LICENSE). We bundle various other libraries (see ./deps) which may have different licenses.

xingyuren/easy_pbr