=======================
  CORONA-13
=======================

this is a plain c testbed for global illumination research code, which has been
used for our projects at the computer graphics group at KIT (https://cg.ivd.kit.edu).

=======================
  QUICKSTART:
=======================

  $ cp arch.example arch
  $ cp config.mk.example config.mk
  $ git fetch
  $ make
  $ ./corona regression/0010_pt/test.nra2

keyboard control:

 [;.]  camera speed -/+ (dvorak)
 [ye]  camera speed -/+ (qwertz)
 [12]  exposure time
 [34]  f-stop
 [56]  focal len
 [78]  iso value
 [c]   save camera position
 [l]   load camera position
 [p]   print screenshot
 [h]   toggle display
 quake movement, use left mouse button to turn


=======================
  REQUIREMENTS:
=======================

m c dl pthread

optional:

GL SDL OpenVDB X11


=======================
  FEATURES:
=======================

ray tracing primitives:
  - triangles, quads, cylinders/lines, spheres/points, distance field shells

acceleration structures:
  - grid
  - qbvh + shadow cache
  - qbvh + motion blur
  - qbvh + motion blur + parallel build

camera models:
  - thinlens + chromatic aberration
  - polynomial optics lens

reflection models: programmable shaders with loadable modules:
  - dielectric (rough/specular)
  - metal (rough/specular)
  - heterogeneous medium/openvdb
  - homogeneous medium
  - texture maps (diffuse, glossy, specular, emission, roughness)
  - may be combined in any way (or: write your own)

point sets used for integration:
  - simple and fast mersenne twister (SSE)
  - halton points
  - kelemen metropolis sampling
  - veach metropolis sampling:
    - large steps/bidirectional mutation
    - multi chain
    - lens perturbation
    - vertex area sampling
    - half vector space perturbation
    - combined hslt

render modes:
  - visibility and aov only
  - timing (rdtsc shading)
  - global illumination
  - gradient domain sampling
  - energy redistribution path tracing

sampling methods:
  - pt
  - ptdl
  - lt
  - ptlt
  - bdpt
  - bdpt1
  - ppm
  - ptmnee

colour management:
  - aces
  - ergb (smits' srgb adapted to illuminant E)
  - rec709
  - srgb
  - adobergb
  - xyz

spectral upsampling:
  - smits
  - grid

threading:
  - pinned pthread pool
  - affinity file with list of cores

frontend:
  - null: commandline, screenshots
  - xorg: x11
  - gl  : opengl backend
  - net : mpeg stream over tcp

screenshots:
  - pfm : portable float maps

tools:
  - convert pfm2exr, pfm2hdr, exr2dng
  - dbor firefly removal
  - obj2geo
  - netrender viewer
  - turntable camera creation
  - bsdf battle tester

regression tests


=======================
  BUILD AND INSTALL:
=======================

corona-13 follows a compile-your-own build strategy. rather than allowing a lot
of run-time options, most of the flexible modules are fixed at compile time.

you can edit these settings in the file config.mk:

 $ cp config.mk.example config.mk
 $ cp arch.example arch

and pick the modules you like best. also have a look at the file arch to suit
your hardware.

 $ make

mpeg stream rendering:

corona features a render server interface through corona-net, built with
MOD_display=network. to use this, start corona as usual on the server. corona
will block and wait for a client connection.  you can initiate one by typing

 $ make corona-netrender -C tools/
 $ tools/corona-netrender <ip-address or hostname>

client side. maybe you need to tunnel it through a firewall by using ssh before
launching corona-netrender:

 $ ssh -f hostname -L 8090:hostname:8090 -N

enjoy!


=======================
  ACKNOWLEDGEMENTS:
=======================

contributors:
  neospark, daylight model, photon kd,
            endless ideas (sky quad sampling, qbvh)
            (GPLv3)
  leo,      halton points
  john,     pthread-pool


=======================
  CHANGES:
=======================

13-th generation rt
(corona-13) : path space api, new geo backend, new threading backend, veach metropolis.

(corona-14) : simulated shading/ray tracing reordering

(corona-12) :
(corona-11) :
(corona-10)
 `real-time rayes' : same on GPU with motion blur
(corona-9)
 `rayes'    : reyes style ray tracing with reordering
(corona-8)  : procedural geo voxel octree ray tracing
(corona-7)  : triangle mesh voxelized and ray traced
(corona-6)
 `radiata'  : spectral rendering!
(corona 5)
 `riot'     : ray i/o tracer, optimized for SIMD and FPGA
(corona 4)
 `mod-rt'   : c99, cp inheritance, unbiased light transport: pt, ptdl, lt
(corona 3)
 `int-rt'   : c99, cpp inheritance, lafortune-style bdpt, integer arith
(corona 2)
 `spiessert': C++ inheritance, ray packets, boring state-of-the-art:
              bih, kd[-ondemand] (parallel)
(corona 1)
 `rearview' : npr, realtime, voxel based