Difference between revisions of "Deuces"

Line 86: Line 86:
 
* include/wdb.h
 
* include/wdb.h
 
* src/libwdb/*.c
 
* src/libwdb/*.c
 
== Fix 'analyze' command output formatting ==
 
 
BRL-CAD has an interactive geometry editor called MGED.  MGED has several hundred commands including an "analyze" command that reports basic statistics such as bounding box size for a given geometry object.  Over time, the output format of the analyze command has become misaligned and disorganized with messy printing.
 
 
This task involves cleaning up the basic printf-style printing so that columns line up neatly and the ornamental ascii table lines are properly aligned.  The table lines should be rewritten to automatically expand as needed for the content being printed so it doesn't become a repeat maintenance burden in the future.
 
 
Code:
 
* src/libged/analyze.c
 
 
== Camera 360: A script to capture images while rotating the view around a scene ==
 
 
BRL-CAD allows the viewing angle for a scene to be set through a number of parameters. These are the azimuth, elevation, twist and also the amount of zoom for the scene. To render a scene a user first sets the view in MGED and then saves the view parameters in a BASH script. This script contains a call to the BRL-CAD ray tracing tool '''rt'''. The appropriate settings to its command line flags are written such that the images are rendered from the view set by the user in MGED.
 
 
The command for invoking rt may be called multiple times in a loop, each time carrying out a small change in the scene such as translating some geometry to achieve basic animation.
 
 
This task involves developing a bash script that changes the parameters to rt in every loop iteration such that the view camera revolves around the origin of the scene at a particular distance from it , in the XY plane. The camera should change the view in small increments such that the images are captured in small angular increments. This would allow a video to be created with the effect of walking around a model while inspecting it from all sides.
 
 
Note: that an equivalent effect could also be achieved by keeping the view steady but revolving the model gradually by 360 degrees instead.
 
 
Code:
 
* src/**/*.c
 
  
 
== Close MGED when both its windows are closed ==
 
== Close MGED when both its windows are closed ==
  
BRL-CAD has an interactive geometry editor called MGED. It's often the starting point for beginners and allows creation and manipulation of models using commands. When MGED is invoked, then it creates 2 windows :  
+
BRL-CAD has an interactive geometry editor called MGED. It's often the starting point for beginners and allows creation and manipulation of models using commands. When MGED is invoked, it creates 2 windows: a text-console command window and an interactive graphics window. When the user closes one of those windows, there is a bug.  Closing the graphics window closes the command window. Even if both windows are manually closed, the MGED process is not terminated.
* A command window
+
* An OpenGL graphics window.
+
 
+
A user types command in the command window and views the results in the graphics window. However when the application is closed then it has a non-intuitive behavior in the sense that even if both the windows are manually closed, the MGED process is not terminated. Thus the proper way of closing it is through the exit command in the MGED command window.
+
  
This task involves fixing this behavior such that closing ''both'' the windows terminates the process properly.  
+
This task involves fixing this behavior so that ONLY closing ''both'' windows terminates the process properly and that closing either window does not take the other along with it.
  
 
Code:
 
Code:
 
* src/mged/mged.c
 
* src/mged/mged.c
 +
* src/tclscripts/mged/openw.c
  
 
== Implement parallel support for Windows ==
 
== Implement parallel support for Windows ==
  
BRL-CAD works pervasively on symmetric multiprocessing (SMP) systems, i.e. computers with multiple CPUs or cores.  However, support for SMP is implemented for each distinct platform.  BRL-CAD runs on Windows, but presently only in a single-threaded mode.
+
BRL-CAD works pervasively on symmetric multiprocessing (SMP) systems, i.e. computers with multiple CPUs or cores.  However, support for SMP is implemented for each distinct platform.  BRL-CAD runs on Windows, but presently only in a single-threaded mode.  To make it work in parallel, we need to define how threads are created (e.g., CreateThread()) and how to acquire a threading lock.
  
 
This task involves implementing the hooks necessary to make BRL-CAD work in parallel on Windows.  This can be achieved with relatively minor source code modifications to two files.
 
This task involves implementing the hooks necessary to make BRL-CAD work in parallel on Windows.  This can be achieved with relatively minor source code modifications to two files.
Line 136: Line 111:
 
BRL-CAD has a 3D display manager library (LIBDM) and a geometry editor command library (LIBGED).  For clean encapsulation and library management, it's desirable to keep library dependencies to a minimum.  LIBGED presently makes direct calls to LIBDM for a "screengrab" command.  Properly fixed, it should be possible to remove the LIBDM linkage from LIBGED's build file and the command still work as expected.
 
BRL-CAD has a 3D display manager library (LIBDM) and a geometry editor command library (LIBGED).  For clean encapsulation and library management, it's desirable to keep library dependencies to a minimum.  LIBGED presently makes direct calls to LIBDM for a "screengrab" command.  Properly fixed, it should be possible to remove the LIBDM linkage from LIBGED's build file and the command still work as expected.
  
This task involves breaking the dependency of LIBGED on LIBDM by making LIBGED not directly call any LIBDM functions.  To do this, LIBGED will likely need to introduce a callback mechanism in the "ged" struct so that the screengrab command can capture an image without directly calling a LIBDM function.
+
This task involves breaking the dependency of LIBGED on LIBDM by making LIBGED not directly call any LIBDM functions.  To do this, LIBGED will need to introduce a callback mechanism in the "ged" struct so that the screengrab command can capture an image without directly calling a LIBDM function.
  
 
Code:
 
Code:
Line 144: Line 119:
 
* src/libged/CMakeLists.txt
 
* src/libged/CMakeLists.txt
  
== implement runtime detection of SSE ==
+
== Implement runtime detection of SSE ==
  
BRL-CAD will optionally leverage SSE instructions for some operations but SSE-support is set at compile-time.  If you attempt to perform SSE instructions on non-SSE hardware, it'll basically halt the application with an illegal instruction exception.   
+
BRL-CAD will optionally leverage SSE instructions for some operations but SSE-support is set at compile-time.  If you attempt to perform SSE instructions on non-SSE hardware, it'll basically halt the application with an illegal instruction exception.  That's a fancy way of saying it crashes.
  
This task involves implementing a new libbu function that reports whether SSE support is available at runtime.  The most prevalent method for doing this is demonstrated by the Mesa folks where you set up an exception handler for SIGILL and attempt an SSE instruction.  That's obviously a non-solution for Windows platforms, but is better than nothing and more useful than a Windows-only solution.  Even better if you can handle both.
+
This task involves implementing a function (that will go into our LIBBU utility library) to reports whether SSE support is available at runtime.  The most prevalent method for doing this is demonstrated by the Mesa folks where you set up an exception handler for SIGILL and attempt an SSE instruction.  That's obviously a non-solution for Windows platforms, but is better than nothing and more useful than a Windows-only solution.  Even better if you can handle both or implement a cross-platform solution.  You'll implement a bu_sse_init() function that returns an error if SSE is not available at runtime.
  
 
Code:
 
Code:
 
* include/bu.h
 
* include/bu.h
* src/libbu
+
* src/libbu/sse.c
  
== Fix Bounding Box function for BoT primitive ==
+
== Fix bounding box function for our polygonal mesh (BoT) primitive ==
  
 
BRL-CAD provides functions for its geometric primitives that define a bounding box - a box that completely encloses the volume described by the primitive.  Ideally, these boxes are as small as possible while still enclosing the primitive.  Currently the routine for BoTs is incorrect.
 
BRL-CAD provides functions for its geometric primitives that define a bounding box - a box that completely encloses the volume described by the primitive.  Ideally, these boxes are as small as possible while still enclosing the primitive.  Currently the routine for BoTs is incorrect.
  
This task involves studying the current code for the function rt_bot_bbox and determining what is causing the current inaccuracies (the bb command is a good way to visualize primitive bounding boxes) and making changes to produce a more optimal bounding box.  The raytracing prep code in rt_bot_prep does prepare a better bounding box, so that is one place to check.
+
This task involves studying the current code for the function rt_bot_bbox() and determining what is causing the current inaccuracies (the bb command is a good way to visualize primitive bounding boxes) and making changes to produce a more optimal bounding box.  The raytracing prep code in rt_bot_prep does prepare a better bounding box, so that is one place to check.
  
 
Code:
 
Code:
* src/librt/primitives/bot/bot.c (the rt_bot_bbox function)
+
* src/librt/primitives/bot/bot.c
  
 
== Implement a primitive UV-mapping callback ==
 
== Implement a primitive UV-mapping callback ==
Line 168: Line 143:
  
 
This task involves implementing a UV-mapping callback for any of the primitives that do not already have a functional UV-callback defined.
 
This task involves implementing a UV-mapping callback for any of the primitives that do not already have a functional UV-callback defined.
 +
 +
References:
 +
* http://en.wikipedia.org/wiki/UV_mapping
  
 
Code:
 
Code:
* src/librt/primitives/*/*.c
+
* src/librt/primitives/[PRIMITIVE]/[PRIMITIVE].c
 
* src/librt/primitives/table.c
 
* src/librt/primitives/table.c
 
* include/rtgeom.h
 
* include/rtgeom.h
  
References:
+
=== ... UV-mapping for extruded bitmap objects (EBM) ===
* http://en.wikipedia.org/wiki/UV_mapping
+
=== ... UV-mapping for extruded 2D sketch objects (EXTRUDE) ===
 +
=== ... UV-mapping for gridded volumes (VOL) ===
 +
=== ... UV-mapping for N-faced arbitrary polyhedrons (ARBN) ===
 +
=== ... UV-mapping for superellipsoids (SUPERELL) ===
 +
=== ... UV-mapping for triangle meshes (BOT) ===
 +
=== ... UV-mapping for solid polygonal meshes (NMG) ===
  
 
== Implement a primitive surface area function ==
 
== Implement a primitive surface area function ==
Line 220: Line 203:
 
=== ... volume function for elliptical hyperboloids (EHY) ===
 
=== ... volume function for elliptical hyperboloids (EHY) ===
 
=== ... volume function for hyperboloids of one sheet (HYP) ===
 
=== ... volume function for hyperboloids of one sheet (HYP) ===
=== ... volume function for super ellipsoids (SUPERELL) ===
+
=== ... volume function for superellipsoids (SUPERELL) ===
 
=== ... volume function for extruded bitmaps (EBM) ===
 
=== ... volume function for extruded bitmaps (EBM) ===
 
=== ... volume function for gridded volumes (VOL) ===
 
=== ... volume function for gridded volumes (VOL) ===
Line 250: Line 233:
 
=== ... centroid function for N-faced polysolids (ARBN) ===
 
=== ... centroid function for N-faced polysolids (ARBN) ===
 
=== ... centroid function for extruded sketches (EXTRUDE) ===
 
=== ... centroid function for extruded sketches (EXTRUDE) ===
=== ... centroid function for super ellipsoids (SUPERELL) ===
+
=== ... centroid function for superellipsoids (SUPERELL) ===
 
=== ... centroid function for solid polygonal meshes (NMG) ===
 
=== ... centroid function for solid polygonal meshes (NMG) ===
  

Revision as of 22:46, 5 November 2012

This is a list of really quick projects that are expected to take most people less than two hours to complete. It's a great starting point for any new contributor that would like to work on BRL-CAD.

These tasks are all roughly the same complexity with no prior BRL-CAD experience expected. For all tasks, a description is provided along with helpful references and a list of files you'll probably need to edit. Can we make it any easier?

Getting Started

Please do contact us (via IRC or brlcad-devel mailing list) if you have any questions, corrections, comments, or ideas of your own that you'd like to suggest.

We've made a really awesome virtual disk image that has everything you need included, preconfigured, and ready to be edited. Here's what you do:

  1. Download our image
  2. Download and run VirtualBox
  3. Get started compiling!

Contents

Code


Tasks related to writing or refactoring code

Move comments from source to header files

BRL-CAD uses Doxygen source code comments to document the API. The comments need to be moved from .c source code files to the corresponding .h API header file.

This task involves editing source code to move comments and verifying compilation wasn't broken in the process. See each library below for details.

... move LIBBN comments

There are less than 150 API comments across 17 files in LIBBN that need to be moved. This will find most of them:

grep -n -r -E '^/\*\*$' src/libbn | grep -v svn | grep -v '\*\*\*' | grep -v '@'

Move all the comments that have a corresponding BN_EXPORT declaration in the include/bn.h header. It should take less than 30 seconds to review each one.

Code:

  • include/bn.h
  • src/libbn/*.c

... move LIBRT comments for files beginning with the letter 'd'

There are approximately 143 public API comments in LIBRT files starting with a 'd' (e.g., src/librt/db_tree.c) that need to be moved. This will find most of them:

grep -n -r -E '^/\*\*' src/librt | grep -v svn | grep -v '\*\*\*' | grep -v '@' |grep 'librt/d'

Move all the comments that have a corresponding RT_EXPORT declaration in the include/raytrace.h header. It should take less than 30 seconds to review each one.

Code:

  • include/raytrace.h
  • include/db.h
  • include/db5.h
  • src/librt/d*.c

... move LIBRT comments for files beginning with a-c and e-o

There are approximately 150 public API comments in LIBRT files starting with 'a', 'b', 'c', (notice we skip 'd' files) 'e', 'f', ... 'n', and 'o'. This will find most of them:

grep -n -r -E '^/\*\*' src/librt | grep -v svn | grep -v '\*\*\*' | grep -v '@' |grep 'librt/[abcefghijklmno]'

Move all the comments that have a corresponding RT_EXPORT declaration in the include/raytrace.h header. It should take less than 30 seconds to review each one.

Code:

  • include/raytrace.h
  • include/db.h
  • include/db5.h
  • src/librt/[abcefghijklmno]*.c
  • src/librt/comb/*.c
  • src/librt/binunif/*.c

... move LIBRT comments for files beginning with 'q' through 'z'

There are approximately 106 public API comments in LIBRT files starting with 'q' through the letter 'z' This will find most of them:

grep -n -r -E '^/\*\*' src/librt | grep -v svn | grep -v '\*\*\*' | grep -v '@' |grep 'librt/[q-z]'

Move all the comments that have a corresponding RT_EXPORT declaration in the include/raytrace.h header. It should take less than 30 seconds to review each one.

Code:

  • include/raytrace.h
  • include/db.h
  • include/db5.h
  • src/librt/[q-z]*.c

... move LIBWDB comments

There are approximately 60 public API comments in LIBWDB files. This will find most of them:

grep -n -r -E '^/\*\*' src/libwdb | grep -v svn | grep -v '\*\*\*' | grep -v '@'

Move all the comments that have a corresponding WDB_EXPORT declaration in the include/wdb.h header AND stub in placeholder /** */ comments for any declarations in the header still lacking a comment block. ALSO, remove any 'F U N C T I O N' names that are spaced out from the comments.

Code:

  • include/wdb.h
  • src/libwdb/*.c

Close MGED when both its windows are closed

BRL-CAD has an interactive geometry editor called MGED. It's often the starting point for beginners and allows creation and manipulation of models using commands. When MGED is invoked, it creates 2 windows: a text-console command window and an interactive graphics window. When the user closes one of those windows, there is a bug. Closing the graphics window closes the command window. Even if both windows are manually closed, the MGED process is not terminated.

This task involves fixing this behavior so that ONLY closing both windows terminates the process properly and that closing either window does not take the other along with it.

Code:

  • src/mged/mged.c
  • src/tclscripts/mged/openw.c

Implement parallel support for Windows

BRL-CAD works pervasively on symmetric multiprocessing (SMP) systems, i.e. computers with multiple CPUs or cores. However, support for SMP is implemented for each distinct platform. BRL-CAD runs on Windows, but presently only in a single-threaded mode. To make it work in parallel, we need to define how threads are created (e.g., CreateThread()) and how to acquire a threading lock.

This task involves implementing the hooks necessary to make BRL-CAD work in parallel on Windows. This can be achieved with relatively minor source code modifications to two files.

Code:

  • src/libbu/parallel.c
  • src/libbu/semaphore.c

Decouple LIBDM from LIBGED

BRL-CAD has a 3D display manager library (LIBDM) and a geometry editor command library (LIBGED). For clean encapsulation and library management, it's desirable to keep library dependencies to a minimum. LIBGED presently makes direct calls to LIBDM for a "screengrab" command. Properly fixed, it should be possible to remove the LIBDM linkage from LIBGED's build file and the command still work as expected.

This task involves breaking the dependency of LIBGED on LIBDM by making LIBGED not directly call any LIBDM functions. To do this, LIBGED will need to introduce a callback mechanism in the "ged" struct so that the screengrab command can capture an image without directly calling a LIBDM function.

Code:

  • include/ged.h
  • include/dm.h
  • src/libged/screengrab.h
  • src/libged/CMakeLists.txt

Implement runtime detection of SSE

BRL-CAD will optionally leverage SSE instructions for some operations but SSE-support is set at compile-time. If you attempt to perform SSE instructions on non-SSE hardware, it'll basically halt the application with an illegal instruction exception. That's a fancy way of saying it crashes.

This task involves implementing a function (that will go into our LIBBU utility library) to reports whether SSE support is available at runtime. The most prevalent method for doing this is demonstrated by the Mesa folks where you set up an exception handler for SIGILL and attempt an SSE instruction. That's obviously a non-solution for Windows platforms, but is better than nothing and more useful than a Windows-only solution. Even better if you can handle both or implement a cross-platform solution. You'll implement a bu_sse_init() function that returns an error if SSE is not available at runtime.

Code:

  • include/bu.h
  • src/libbu/sse.c

Fix bounding box function for our polygonal mesh (BoT) primitive

BRL-CAD provides functions for its geometric primitives that define a bounding box - a box that completely encloses the volume described by the primitive. Ideally, these boxes are as small as possible while still enclosing the primitive. Currently the routine for BoTs is incorrect.

This task involves studying the current code for the function rt_bot_bbox() and determining what is causing the current inaccuracies (the bb command is a good way to visualize primitive bounding boxes) and making changes to produce a more optimal bounding box. The raytracing prep code in rt_bot_prep does prepare a better bounding box, so that is one place to check.

Code:

  • src/librt/primitives/bot/bot.c

Implement a primitive UV-mapping callback

BRL-CAD provides more than two dozen types of geometry "primitives" such as ellipsoids, boxes, and cones. Every primitive is described by a collection of callback functions, for example rt_ell_bbox() returns the bounding box dimensions for an ellipsoid. One of those functions describes a UV mapping of the object's surface, which is used for things like texture and bump mapping. An example of this is rt_ell_uv() in the src/librt/primitives/ell/ell.c source file for an ellipsoid. Several of our more complex primitive types (such as BoT, NMG, and BREP/NURBS) do not presently implement a UV-mapping function leading to unexpected runtime behavior.

This task involves implementing a UV-mapping callback for any of the primitives that do not already have a functional UV-callback defined.

References:

Code:

  • src/librt/primitives/[PRIMITIVE]/[PRIMITIVE].c
  • src/librt/primitives/table.c
  • include/rtgeom.h

... UV-mapping for extruded bitmap objects (EBM)

... UV-mapping for extruded 2D sketch objects (EXTRUDE)

... UV-mapping for gridded volumes (VOL)

... UV-mapping for N-faced arbitrary polyhedrons (ARBN)

... UV-mapping for superellipsoids (SUPERELL)

... UV-mapping for triangle meshes (BOT)

... UV-mapping for solid polygonal meshes (NMG)

Implement a primitive surface area function

BRL-CAD provides more than two dozen types of geometry "primitives" such as ellipsoids, boxes, and cones. Every primitive is described by a collection of callback functions, for example rt_ell_bbox() returns the bounding box dimensions for an ellipsoid. Wikipedia, Wolfram Mathworld, and various other math sites (and research papers) around the web include the equations for most of our basic primitives while others are a little more tricky to compute.

This task involves writing a new callback function that takes an rt_db_internal object and calculates the surface area (units are mm^2). There are numerous examples in our code where we compute surface area for other primitives. The primitives that do not already have a centroid callback are itemized in following.

References:

Code:

  • src/librt/primitives/[PRIMITIVE]/[PRIMITIVE].c

... surface area function for elliptical hyperboloids (EHY)

... surface area function for right hyperbolic cylinders (RHC)

... surface area function for hyperboloids of one sheet (HYP)

... surface area function for polyhedron with 4 to 8 sides (ARB8)

... surface area function for N-faced polysolid (ARBN)

... surface area function for extruded bitmaps (EBM)

... surface area function for gridded volumes (VOL)

... surface area function for super ellipsoids (SUPERELL)

... surface area function for polygonal meshes (NMG)

... surface area function for triangle meshes (BOT)

... surface area function for NURBS objects (BREP)

Implement a primitive volume function

BRL-CAD provides more than two dozen types of geometry "primitives" such as ellipsoids, boxes, and cones. Every primitive is described by a collection of callback functions, for example rt_ell_bbox() returns the bounding box dimensions for an ellipsoid. Wikipedia, Wolfram Mathworld, and various other math sites (and research papers) around the web include the equations for most of our basic primitives while others are a little more difficult to compute.

This task involves writing a new callback function that takes an rt_db_internal object and calculates the volume (units are mm^3). There are numerous examples in our code where we compute volume for other primitives. The primitives that do not already have a volume callback are itemized in following.

References:

Code:

  • src/librt/primitives/[PRIMITIVE]/[PRIMITIVE].c

... volume function for right hyperbolic cylinders (RHC)

... volume function for elliptical hyperboloids (EHY)

... volume function for hyperboloids of one sheet (HYP)

... volume function for superellipsoids (SUPERELL)

... volume function for extruded bitmaps (EBM)

... volume function for gridded volumes (VOL)

... volume function for triangle meshes (BOT)

... volume function for solid polygonal meshes (NMG)

... volume function for extruded sketches (EXTRUDE)

Implement a primitive centroid function

BRL-CAD provides more than two dozen types of geometry "primitives" such as ellipsoids, boxes, and cones. Every primitive is described by a collection of callback functions, for example rt_ell_bbox() returns the bounding box dimensions for an ellipsoid. Wikipedia, Wolfram Mathworld, and various other math sites (and research papers) around the web include the equations for most of our basic primitives while others are a little more tricky to compute.

This task involves writing a new callback function that takes an rt_db_internal object and calculates its centroid (as a point_t 3D point). There are numerous examples in our code where we compute centroids for other primtiives. The primitives that do not already have a centroid callback are itemized in following.

References:

Code:

  • src/librt/primitives/table.c
  • src/librt/primitives/[PRIMITIVE]/[PRIMITIVE].c

... centroid function for elliptical hyperboloids (EHY)

... centroid function for right hyperbolic cylinders (RHC)

... centroid function for hyperboloids of one sheet (HYP)

... centroid function for polyhedron with 4 to 8 sides (ARB8)

... centroid function for extruded bitmaps (EBM)

... centroid function for gridded volumes (VOL)

... centroid function for N-faced polysolids (ARBN)

... centroid function for extruded sketches (EXTRUDE)

... centroid function for superellipsoids (SUPERELL)

... centroid function for solid polygonal meshes (NMG)


Documentation and Training


Tasks related to creating/editing documents and helping others learn more about BRL-CAD

Add missing documentation (for JUST ONE command)

BRL-CAD is an extensive system with more than 400 commands and more than a million pages of documentation, but there are approximately 120 commands that are entirely undocumented:

a-d archer asc2g asc2pix bot-bldxf bottest brep_cube brep_simple brickwall btclsh burst bw-a bw-d bwish c-d chan_add clutter contours d-a damdf dauto dauto2 d-bw dconv ddisp d-f dfft d-i dmod double-asc dpeak dsel dsp_add dstat d-u dwin euclid_format euclid_unformat fbgammamod f-d fence fhor f-i g-adrt g-euclid1 g-jack globe g-off i-a i-d i-f ihist imod istat jack-g kurt lowp molecule nmgmodel nmg-sgp off-g pipe pipetest pix2g pix3filter pixcount pixelswap pixembed pixfields pixfieldsep pixflip-fb pixpaste pix-spm pix-yuv plstat pyramid rawbot remapid rlesortmap rletovcr room rtcell rtexample rtfrac rtrad rtsil rtsrv script-tab sketch solshoot sphflake spltest spm-fb ssampview syn tea tea_nmg testfree texturescale torii ttcp tube txyz-pl u-a u-bw u-d u-f umod ustat vcrtorle vegitation wall wdb_example xbmtorle xyz-pl yuv-pix

This task involves writing a failed document for JUST ONE of those commands in the Docbook format. The command documentation should provide a one-sentence description, a detailed paragraph description, explanation of all available command-line options, and one or more examples on how to use the command.

Code:

  • doc/docbook/system/man1/en/Makefile.am
  • doc/docbook/system/man1/en/*.xml

Write "MGED Interface" reference document

BRL-CAD's primary geometry editor is called MGED. MGED's documentation is extensive but incomplete without a concise 1 or 2 page document that details MGED's interface.

This task involves writing an interface reference document that gives a brief descriptive overview of the key bindings, mouse bindings, and primary GUI elements. The shift grips reference should be incorporated, albeit much more concisely and organized.

References:

Convert src/conv man pages to valid Docbook

BRL-CAD is in the process of converting its documentation into Docbook 4.5 format, in order to enable automatic generation of output in different formats (html, pdf, man) from a single source. This conversion includes existing UNIX man pages.

This task involves using the doclifter tool to perform a rough conversion to Docbook of all man pages in the src/conv subdirectory of the BRL-CAD source tree (about 40 files), then performing whatever manual corrections are needed to the autogenerated xml files to make them valid Docbook (some conversions have already been done and can serve as guides). The simplest way to confirm the files are successfully converted is to incorporate them into BRL-CAD's build logic for Docbook man pages and view the output using brlman and an html viewer. It is recommended to use the Emacs editor with the nxml mode in order to more easily identify and fix errors, but this is not a requirement.

References:

Write a "BRL-CAD Commands Quick Reference" document

There is already a command quick reference for BRL-CAD's MGED geometry editing tool, but there is not a similar document for BRL-CAD's 400+ command-line commands.

This task involves writing a quick reference document similar to the MGED quick reference but for BRL-CAD commands.

References:

LIBBU Doxygen cleanup

BRL-CAD uses Doxygen for most API documentation but the comment blocks are not optimally set up for Doxygen output. There are approximately 300 documented API function calls in LIBBU.

This task involves cleaning up the Doxygen comments in the library so that useful reports and API documentation is automatically generated (correctly and completely).

Code:

  • include/bu.h
  • src/libbu
  • misc/Doxyfile
  • ./configure --enable-documentation

References:

LIBBN Doxygen cleanup

BRL-CAD uses Doxygen for most API documentation but the comment blocks are not optimally set up for Doxygen output. There are approximately 300 documented API function calls in LIBBN.

This task involves cleaning up the Doxygen comments in the library (i.e., all of the /** */ comments) so that useful reports and API documentation is automatically generated (correctly and completely). The comments should be cleanly wrapped to column 70 with minimal or no embedded leading whitespace.

Code:

  • include/bn.h
  • include/plot3.h
  • include/vmath.h
  • src/libbn
  • misc/Doxyfile
  • ./configure --enable-documentation

References:

LIBWDB Doxygen cleanup

BRL-CAD uses Doxygen for most API documentation but the comment blocks are not optimally set up for Doxygen output. There are approximately 100 documented API function calls in LIBWDB.

This task involves cleaning up the Doxygen comments (i.e., all of the /** */ comments) in the library so that useful reports and API documentation is automatically generated (correctly and completely). The comments should be cleanly wrapped to column 70 with minimal or no embedded leading whitespace.

Code:

  • include/wdb.h
  • include/raytrace.h
  • src/libwdb
  • misc/Doxyfile
  • ./configure --enable-documentation

References:

LIBRT Doxygen cleanup

BRL-CAD uses Doxygen for most API documentation but the comment blocks are not optimally set up for Doxygen output. There are approximately 1000 documented API function calls in LIBRT.

This task involves cleaning up the Doxygen comments (i.e., all of the /** */ comments) in the library so that useful reports and API documentation is automatically generated (correctly and completely). The comments should be cleanly wrapped to column 70 with minimal or no embedded leading whitespace.

Code:

  • include/raytrace.h
  • src/librt
  • src/librt/primitives
  • src/librt/comb
  • src/librt/binunif
  • misc/Doxyfile
  • ./configure --enable-documentation

References:

"Introduction to BRL-CAD Tutorial"

BRL-CAD includes an extensive introduction to MGED tutorial series, but not a succinct introduction to BRL-CAD (the suite).

This task involves writing a brief introduction to BRL-CAD that highlights 10-20 of the core commands through an instructive tutorial. The tutorial should be brief, not exceeding 10 pages total.

Write a "BRL-CAD Ray Tracing Shaders" tutorial

BRL-CAD includes numerous shaders that let you specify different optical effects during ray tracing.

This task involves writing a brief tutorial that describes what shaders are and how one specifies them for geometry. How shaders are specified is already described in detail in the Introduction to MGED document.

Code:

  • src/liboptical/sh_*.c (for available shader names and corresponding options)

References:


Outreach


Tasks related to community management and outreach/marketing

Write solicitation for new website designer

The BRL-CAD website is in need of a design overhaul.

This task involves writing up a brief article soliciting new contributor(s) to work on designing a new website. The article needs to be detailed and specific to our particular website requirements (Drupal+Mediawiki+CSS) to ensure the contributor can design the appropriate stylesheet(s), updated graphics, and new layout.

References:

Model new BRL-CAD Logo using BRL-CAD

The winner of the recent BRL-CAD Logo contest is a clean depiction of two interlocked components. Modeling the new Logo in BRL-CAD without using NURBS would require some careful arrangement, but would provide an attractive three dimensional rendering.

The output of this task would be a .asc file of BRL-CAD geometry (converted via g2asc) for inclusion in the db/ example directory. Optimally, the two segments would overlap at the join, but this is your opportunity as an artist and 3D magician to shine with your interpretation.

References:

Write BRL-CAD News article on .deb/.rpm builds

BRL-CAD has a new maintainer, Jordi Sayol, for managing .deb and .rpm builds. Interview the developer, obtain details on how the releases are produced, what platforms are supported, etc, and write up an article for our Community Publication Portal (CPP)

The output of this task is an article added to our CPP wiki page in a final production-quality review state.

References:

Write a BRL-CAD model showcase article

BRL-CAD has several geometry models developed by community members that showcase the power and applicability of BRL-CAD to various domains. For this task, you'd be expected to interview one or more individuals to obtain information and pictures about their project, write up a descriptive overview of their model, the goals of the project, and any interesting ancillary information that may be relevant. There are presently several candidate topics listed in our Community Publication Portal (CPP).

The output of this task is an article added to our CPP wiki page in a final production-quality review state.

References:

Design a "Commercial CAD Comparison" diagram

New users frequently ask how BRL-CAD compares to other major commercial CAD systems such as CATIA, Unigraphics/NX, Pro/ENGINEER, Solidworks, and AutoCAD. BRL-CAD has many of the same features and it would be very useful to visualize the feature overlap graphically with a diagram.

This task involves identifying core significant features of relevance and describing BRL-CAD along with the various major CAD vendors. The diagram should fit on one page.

References:


Research


Tasks related to studying a problem and recommending solutions

Investigate performance of setting thread affinity

BRL-CAD's raytrace library (LIBRT) is pervasively multithreaded using routines defined in our basic utility library (LIBBU) for detecting an using multiple CPUs/cores/threads.

This task involves making minor modifications to the LIBBU parallel interface using sched_setaffinity and/or pthread_attr_setaffinity_np (or similar affinity mechanism depending on the platform) and then evaluating the performance impact using our BRL-CAD Benchmark suite ('benchmark' command).

Code:

  • src/libbu/parallel.c
  • src/libbu/semaphore.c

Determine why solids.sh fails on 64-bit

BRL-CAD has a regression test script called solids.sh that creates a bunch of primitives, renders an image of those primitives, and then compares that image to a reference image. On (most?) 64-bit platforms, the test is off by several RGB values for exactly 3 pixels.

This task involves figuring out why, exactly, this is occurring. It may be helpful to compare intermediate computation results from a 32-bit environment to see where the computations diverge, however slightly. Ultimately, the goal is to identify the cause and a recommended course of action to fix the divergence problem.

Code:

  • regress/solids.sh

Investigate permuted vertex lists from g-iges + iges-g

BRL-CAD has a geometry exporter and importer for the International Graphics Exchange Standard (IGES) file format. If you run our g-iges exporter on some geometry, then run iges-g on that same geometry to import it back to BRL-CAD format, the geometry will have permuted vertex lists. Particularly for geometry already in polygonal format, such as our NMG or BoT geometry, this conversion should result in identical geometry but presently does not.

This task involves investigating why this occurs, reporting (in detail) why it occurs, and if obvious, making a recommendation on how to fix the problem.

Code:

  • src/conv/iges

Investigate GMP integration

BRL-CAD uses a fastf_t typedef for most all math operations that is usually a "double" floating point type. We would like to provide the option for resorting to exact arithmetic if possible by merely redefining fastf_t to a C++ type sufficiently overloaded to behave the same.

This task would involve implementing a C++ class with overloaded operators such that vmath macro calls still work as well as a sampling of LIBBN API function calls without major changes to the original code. A perfect example case study would be creating the class then testing whether bn_dist_pt3_pt3() and bn_mat_determinant() compute correctly for values that cannot be exactly represented with floating point arithmetic.

Code:

  • include/vmath.h
  • include/bn.h

References:

Investigate the status of our command spreadsheet

We have a spreadsheet filled with information about all of BRL-CAD's 400+ commands including details about what command line options, inputs, and outputs are supported. The spreadsheet is not complete, however, and hasn't been reviewed in a couple years.

This task involves comprehensively going over the 400+ rows of the spreadsheet to systematically verify that the information is complete and correct, and to fill in missing information where needed. This task requires strong familiarity with the UNIX command line, manual pages, and how to pipe input to/from applications in a variety of formats.

Code:

  • src/ .. everywhere

References:

  • Existing spreadsheet available on request

Quality Assurance


Tasks related to testing and ensuring code is of high quality

Develop an N-Manifold Geometry (NMG) testing framework

BRL-CAD implements polygonal facetted geometry as "NMG" geometry, which is then used for converting from an implicit constructive solid geometry (CSG) representation to a mesh format. This is a huge portion of BRL-CAD's core libraries that is used by dozens of tools and commands so there is a need for improved robustness.

This task involves custom scripting or using a testing framework (such as googletest) that attempts to convert all of BRL-CAD's provided sample geometry into NMG format. There are more than 500 functions in the NMG code, so this task only exercises the NMG code indirectly through one of BRL-CAD's numerous geometry exporters such as g-nmg or g-dxf. The testing should report which objects do not successfully convert and percentage conversion success.

Files:

  • db/*.g
  • src/conv/g-nmg

References:

Create comprehensive utility library (LIBBU) API unit tests

There are more than 300 library functions in our core LIBBU library. As a core library used by nearly every one of BRL-CAD's tools, testing those functions for correct behavior is important.

This task involves implementing a testing framework for LIBBU that exercises every single one of the public API C function calls and reports whether tests pass successfully or not.

Code:

  • include/bu.h
  • src/libbu

References:

Create comprehensive numerics library (LIBBN) API unit tests

There are more than 300 library functions in our core LIBBN library. As a core library used by nearly every one of BRL-CAD's tools, testing those functions for correct behavior is important.

This task involves implementing a testing framework for LIBBN that exercises every single one of the public API C function calls and reports whether tests pass successfully or not.

Code:

  • include/bn.h
  • include/plot3.h
  • include/vmath.h
  • src/libbn

References:

Create a comprehensive unit test for bn_dist_pt3_pt3()

There are more than 300 library functions in our LIBBN numerics library. Creating a comprehensive unit test involves exhaustively exploring all possible inputs to the function, testing them for proper behavior, and characterizing the output in a PASS/FAIL fashion.

Unlike the other testing framework tasks, the goal of this task is comprehensiveness. The task must cover all possible inputs including NULL, -inf, +inf, NaN, real numbers, and other values in most if not all possible combinations.

Code:

  • include/bn.h
  • src/libbn

References:

Find, reproduce, confirm, and report any bug in Archer

Archer is our new modeling interface and a soon-to-be replacement for our long-standing MGED geometry editor. It undoubtedly has bugs. It's your job to find them, but do so in a manner that is so obvious that one of the other devs will be able to instantly reproduce the bug given your instructions. Crashing bugs are best, but may require learning how to use the tool with minimal documentation.

This task involves filing a bug report with verifiable and reproducible steps that clearly demonstrate the bug. It can't be a bug already reported or otherwise documented.

References:


User Interface


Tasks related to user experience research or user interface design and interaction

Design an MGED command spreadsheet

BRL-CAD's primary solid geometry modeling application is called MGED. MGED contains a comprehensive set of more than 700 commands for manipulating, viewing, and inspecting geometry. There is a need to more effectively manage those commands, characterize them all, and get a "big picture" of the command landscape so that usability may be addressed.

This task involves designing a spreadsheet that will be used to characterize all of MGED's commands.

References:

  • An existing spreadsheet already being used for BRL-CAD (i.e., non-MGED) commands is available.

Create prototype 2D CAD drawing(s)

BRL-CAD provides limited services for drafting features including the production of 2D CAD drawings (blueprints).

This task involves designing a 2D CAD drawing prototype that effectively captures a set of design requirements and follows industry conventions. Basically, this requires identifying one or more style(s) of drawings that should be supported along with critical elements to be included on each drawing.

References:

Create prototype CAD GUI layout diagram

BRL-CAD's usability is notoriously complex and "expert friendly". MGED and Archer are the main geometry editors, with drastically different user interfaces.

This task involves evaluating the features provided by MGED and Archer, then designing a new GUI layout that encompasses their features while improving usability. Rationale for design decisions and layout should be provided.

References:

Reorganize MGED menu

BRL-CAD's main graphical user interface, MGED, is heavily menu-driven but not exceptionally well organized. This task involves performing an exhaustive review of MGED's various menus, including temporary menus when in a given editing state, reorganizing them for logical groupings, and rewording them for clarity. It's necessary to learn the basics of the MGED interface in order to understand what the various options do.

For this task, you'll provide a description of the existing menus and mapping to a new organization including basic rationale behind any new groupings or rewording.

References:

Categorize all of BRL-CAD's commands into a spreadsheet

BRL-CAD is a suite of more than 400 processing tools, image tools, geometry converters, and more. There is an existing spreadsheet that characterizes all of the available commands in terms of inputs, outputs, and options, but there is insufficient characterization of BRL-CAD's commands as to how they logically group and work together.

This task involves building up a spreadsheet that lists all of our commands, describing a finite set of command categories, and characterizing all commands into those categories while filling in the spreadsheet with details for each command.

References:

  • A spreadsheet template will be provided.

Template example title

This is a template for mentors adding new ideas. Brief background information not specific to the task is listed first. It's succinct.

This task involves ... the rest goes here. Remember, less than two hours expected for average or random contributor to do the work after reading this description. The resulting task should be directly measurable without subjective interpretation. Tell them exactly what they need to do. Be specific.

References:

  • optionally list any url's that provide relevant background information

Code:

  • list any files you know they will need to read/edit