CMSC 740 Fall 2017 is taught by an awesome teacher Prof. Matthias Zwicker.
Projects
The course project is based on Nori, an educational ray tracer.
Notes
Acceleration structures,
Uniform grid
Object subdivision
Bounding volume hierarchies (BVHs)
Partition space into non-overlapping cells
Each cell stores reference to all objects
that overlap it
Spatial subdivision
Binary space partitioning (BSP) trees
Recursively divide space into two parts using
dividing planes (with arbitrary position,
orientation)
k-d-trees, nearest neighbor search
Light Transport Effects
Fluorescence
Reflection
Thin film interference: https://www.shadertoy.com/view/XddXRj
Diffraction
Refraction
Dispersion
Rayleigh Scattering: https://www.shadertoy.com/view/MdXSzX (Subsurface Scattering)
Polarization
Radiometry
Quantify spatial energy distribution of light
(in a way that is compatible with the geometrical optics model)
Physical measurement of electromagnetic energy
Unit: Watts
Assume light consists of photons with
Position x
Direction of motion w
Wavelength lambda
Each photo has an energy of hv
H Planck’s constant
V = 1 / lambda frequency
Measuring energy means “counting photons”
Spectral Radiance
Energy per time per wavelength per solid angle per area
means differetial area perpendicular to
Power carried along a ray is measured in radiance
Radiance along ray is constant (in vacuum)
In practice: assume steady state, measure at discrete wavelengths R, G, B
Radiance L: power per solid angle per area, vector of 3 values for R, G, B
Irradiance: Power per unit area
Integration of radiance over hemisphere
Irradiance E: power per area perpendicular to the surface normal
Radiance L: power per area perpendicular to the incident ray \omega
When we do ray tracing, we use radiance for rays
Integration in spherical coordinates
Radiant intensity I in all direction, has a total power
Photometry
Perceptual measurement of perceived brightness
Lumen
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