User:Kunigami/GSoc2011/OSL Tutorial

Here I provide a small tutorial do make OSL running while it is not included in BRL-CAD source code.

Installing

Installing OSL Dependencies

OIIO

Get the latest OIIO source code

cd /home/dude/dev

mkdir oiio

cd oiio

git clone https://github.com/OpenImageIO/oiio.git .

Note: Change /home/dude/dev/ by the desired install place.

Install (locally)

make

Note1: Some dependecies are required such as Ilmbase, OpenEXR, libpng (please, edit this entry with any additional package you had to install)

Note2: Make sure your libpng version is 1.4 (for BRL-CAD compatibility)

OSL

Get the latest OSL source code

cd /home/dude/dev

mkdir osl

cd osl

git clone https://github.com/imageworks/OpenShadingLanguage.git .

Set OIIO path

export OPENIMAGEIOHOME=/home/dude/dev/oiio/dist/macosx/

Note1: Depending on your OS, macosx may be linux, linux64, etc.

Remove -Werror compilation flags

Open the osl/src/CMakeLists.txt file and change lines

 set ( CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror")
 set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror" )

by

 set ( CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall" )

Edit llvm search path

Cmake was not able to find llvm installed on my system. I had to make the following edit. Open the osl/src/cmake/externalpackages.cmake

Change:

 find_library ( LLVM_LIBRARY
 NAMES LLVM-2.7 LLVM-2.8svn LLVM-2.8 LLVM-2.9svn
 PATHS /usr/local/lib /opt/local/lib )
 find_path ( LLVM_INCLUDES llvm/LLVMContext.h
 PATHS /usr/local/include /opt/local/include

by

 find_library ( LLVM_LIBRARY
 NAMES LLVM-2.7 LLVM-2.8svn LLVM-2.8 LLVM-2.9svn
 PATHS /usr/local/lib /opt/local/lib /usr/lib/llvm/lib )
 find_path ( LLVM_INCLUDES llvm/LLVMContext.h
 PATHS /usr/local/include /opt/local/include /usr/include

Install locally

make

Installing BRL-CAD with OSL mode on

Get BRL-CAD

cd /home/dude/dev

mkdir brlcad

cd brlcad

svn co https://brlcad.svn.sourceforge.net/svnroot/brlcad/brlcad/trunk/ brlcad

Set OSL path

export OSLHOME=/home/dude/dev/osl/dist/macosx/

Note1: Depending on your OS, macosx may be linux, linux64, etc.

Install locally

I use the following to set up to install BRL-CAD:

cd /home/dude/dev

mkdir brlcad-build

mkdir brlcad-bin

cd brlcad-build

cmake ../brlcad -DBRLCAD-ENABLE_COMPILER_WARNINGS=OFF -DBRLCAD-ENABLE_ALL_LOCAL_LIBS=ON -DBRLCAD-ENABLE_OSL=ON -DCMAKE_INSTALL_PREFIX=/home/dude/dev/brlcad-bin/ -DBRLCAD-ENABLE_STRICT=OFF

I hope it's enough to have the code compiling. Please, edit this entry with any additional step you needed to perform in order to get it working

Running an example

Compiling some shaders

Use the OSL compiler, oslc, to convert .osl shaders to .oso. Compile all shaders in brlcad/src/other/osl/shaders. For example

cd /home/dude/dev/osl/dist/macosx/bin

./oslc glass.osl

It will generate a glass.oso. Copy it to the directory of binaries of BRL-CAD

cp glass.oso /home/dude/dev/brlcad-bin/bin

Also, copy the scene I've been using to perform tests

cp /home/dude/dev/brlcad/db/cornell-kunigami.g /home/dude/dev/brlcad-bin/bin

Run with the following script:

 #!/bin/sh
 ./rt -M -p55 -P1 -R -H 1000 -J3 -o output.png \
  $*\
  cornell-light.g\
  'all.g' \
  <<EOF
 viewsize 6.000000000000000e+03;
 orientation 0.000000000000000e+00 9.961946980917455e-01 8.715574274765824e-02  0.000000000000000e+00;
 eye_pt 2.780000000000000e+02 3.709445330007912e+02 -4.544232590366239e+02;
 start 0; clean;
 end;
 EOF