BLACKHOLE BEYOND THE GATE
For this renering competition, our team decided to rendered an outer space scene. Using a blackhole as our environment map lighting, we created a simple scene of Naboo star fighter travelling through a portal to get to this blackhole.
In addition to our final rendering, we implemented 4 features that. In the final scene we used the rough-dielectric on the portal and we used the halton sampler as the prefered sampler. The 2 extra features that we have are tone mapping and thin lens camera, which we will introduce in our features implemented section.
FEATURES IMPLEMENTED
ROUGH DIELECTRIC
Rough dielectric bunny rendered with 10 levels path tracer
Relevant code for rough dielectric are found in:
./charizard/src/bsdfs/roughdielectric.cpp
This example is rendered by changing the xml file of pathtracing_depth5.xml
For rough dielectric we followed the papers that was recommended to us in the Teams help. Aside from the we also took reference from Mitsuba 3 github on rough dielectric.
Links of reference resources:
Micro-facet bsdfImportance Sampling Microfacet-Based BSDFs using the Distribution of Visible Normals
Mitsuba 3
Rough dielectric bunny rendered with 10 levels path tracer with Halton sampler (left) and with Independent sampler (right)
Rough dielectric bunny rendered with 10 levels path tracer
Relevant code for halton sampler are found in:
./charizard/src/samplers/HaltonSampler.cpp
This example is rendered by changing the xml file of pathtracing_depth5.xml and the bunny_constant.xml
For Halton Sampler I struggled a lot with the shuffling and jittering. In the end I decided to not implement Owen scramble, I decided to use blue noise jittering. My version of Halton sampling achieved pixel decorrelation (since I don't use the image resolution), but the quality is still not as good in general as Mitsuba 3 Halton Sampling and the Blue Noise paper.
Links of reference resources:
Dithered SamplingMitsuba 3
ROUGH DIELECTRIC
BLACKHOLE BEYONE THE GATE render with thinlens camera (above) and render with perspective camera (below)
Relevant code for rough dielectric are found in:
./charizard/src/cameras/thinlens.cpp
This example is rendered by changing the xml file of submission.xml
For thinlens camera, I used mostly wikipedia and my own implementation of perspective camera to implement thinlens camera. The thin lens render above has this spec:
camera type="thinlens" id="camera" lensRadius="0.0005" focalDistance="0.3"
The bokeh effect is not as good as I hope it to be. From what I've read a more realistic camera model would capture this better.
Links of reference resources:
Thinlens wikipedia
Submission scene rendered (above) compared with tone mapped version (below)
Memorial image tone mapped using Reinhard-Jodie Algorithm
Relevant code for rough dielectric are found in:
./charizard/src/postprocessing/tonemapping.cpp
This example is rendered by the file
./charizard/tests/scene.xml
Links of reference resources:
Tone MappingThe Reinhard-Jodie tone mapping method is a technique used in image processing to convert high dynamic range (HDR) images to low dynamic range (LDR) images, making them suitable for display on standard monitors and printing. Developed by Erik Reinhard and Kate Devlin, this method aims to compress the wide range of luminance values present in HDR images into the narrower range of a display device, while preserving the visual contrast and details. It employs a global tone mapping operator that adjusts luminance based on a logarithmic scale, simulating the human eye's response to light, which naturally compresses high luminance values while retaining low-light details. This method balances overall exposure and contrast, producing images that closely resemble natural human perception.
BROKEN HALTON SAMPLER FOR "BREAKING THINGS COMPETITION"
These are the Cornel rooms with pathtracer 2 levels. The Halton sampler on the left is being sample with the index that increment with the seed change. The one on the right the index is basically a random integer and this created weird noise in the scene (possibly blue noise from the jittering)
Relevant code for rough dielectric are found in:
./charizard/src/samplers/HaltonSampler_broken.cpp