Sharp3D.Math Math Library

CREATED ISSUE: Problems with Minor() and Adjoint()

davidcanar — Wed, 09 Jan 2008 15:22:45 GMT

So trying to extend the library so the Matrices support an "Inverse" function I found that the Minor and Adjoint functions don't work. the reason? The indexing of the Matrices is calculating the index wrong for example:
in Matrix3F Minor() is doing:
for (int iRow = 0; iRow < 3; iRow++)
{
int c = 0;
if (iRow != row)
{
for (int iColumn = 0; iColumn < 3; iColumn++)
{
if (iColumn != column)
{
result[r,c] = this[iRow, iColumn];

the code is accessing "this[0,0]"
but if you check the code for the indexer:

public float this[int row, int column]
{
get
{
return this[(row-1)*3 + column-1];
}
set
{
this[(row-1)*3 + column-1 ] = value;
}
}
This code will produce a negative index. The indexer is expecting rows and columns starting with 1 but the Minor code is accessing the Rows and Columns starting at 0. Fixing the above code to :

public float this[int row, int column]
{
get
{
return this[row*3 + column];
}
set
{
this[ row*3 + column ] = value;
}
}

fixed the problem

NEW POST: Issue tracker

stenio — Tue, 21 Aug 2007 15:04:32 GMT

Hi,

please have a look at the issue tracker. It would be a good thing to know if the issues posted are real issues or not, and the vote system is really a good and simple way to do this job.

Regards,
Stenio

COMMENTED ISSUE: Plane/Segment intersection problem

stenio — Tue, 21 Aug 2007 14:54:02 GMT

Hello,
First of all thank you for this beautiful library!

I'm not sure if I'm using the library in the correct way, but with the following code I get wrong results:
if a segment from point A to point B intersects the plane, also the segment from B to A should intersect, but I get false from the first test.

// z = 0
Plane plane = new Plane(Vector3F.ZAxis, 0);
Vector3F pointA = new Vector3F(0, 0, -10);
Vector3F pointB = new Vector3F(0, 0, 10);
Segment segmentAB = new Segment(pointA, pointB);
Segment segmentBA = new Segment(pointB, pointA);
IntersectionPair intersection = IntersectionMethods.Intersects(segmentAB, plane);
Console.WriteLine(intersection.IntersectionOccurred);
intersection = IntersectionMethods.Intersects(segmentBA, plane);
Console.WriteLine(intersection.IntersectionOccurred);

Many thanks,
Stenio Brunetta
Comments: ** Comment from web user: stenio **

I've posted the previous comment as a new issue, because it seems to be a different kind of problem.

Regards,
Stenio

CREATED ISSUE: Plane/segment intersection problem #2

stenio — Tue, 21 Aug 2007 14:25:28 GMT

Hi,

another issue:

[Test]
public void test() {
Sharp3D.Math.Geometry3D.Plane plane = new Sharp3D.Math.Geometry3D.Plane(Vector3F.ZAxis, -3e6f);

Vector3F p1 = new Vector3F(161746.9f, 0.00571176f, 3195273f);
Vector3F p2 = new Vector3F(279734.7f, 0.004676462f, 2649951f);

Sharp3D.Math.Geometry3D.Segment segment1 = new Sharp3D.Math.Geometry3D.Segment(p1, p2);

Sharp3D.Math.Geometry3D.IntersectionPair intersection = Sharp3D.Math.Geometry3D.IntersectionMethods.Intersects(segment1, plane);

Assert.IsFalse(intersection.IntersectionOccurred);
}

There should be no intersection with the segment because its end points have a positive z.

COMMENTED ISSUE: Plane/Segment intersection problem

stenio — Mon, 20 Aug 2007 15:36:19 GMT

Hi,

another issue:

[Test]
public void test() {
Sharp3D.Math.Geometry3D.Plane plane = new Sharp3D.Math.Geometry3D.Plane(Vector3F.ZAxis, -3e6f);

Vector3F p1 = new Vector3F(161746.9f, 0.00571176f, 3195273f);
Vector3F p2 = new Vector3F(279734.7f, 0.004676462f, 2649951f);

Sharp3D.Math.Geometry3D.Segment segment1 = new Sharp3D.Math.Geometry3D.Segment(p1, p2);

Sharp3D.Math.Geometry3D.IntersectionPair intersection = Sharp3D.Math.Geometry3D.IntersectionMethods.Intersects(segment1, plane);

Assert.IsFalse(intersection.IntersectionOccurred);
}

There should be no intersection with the segment because its end points have a positive z.

NEW POST: Vector3DList and similar

RSaint — Mon, 23 Jul 2007 22:56:24 GMT

Hello,

I was looking at the new sourcecode you've downloaded and I saw that you don't implement itemlists anymore.
Is this part of the code cleaning process, or has to do with the use of Generics?

Also, I need some help, if you can provide it. I'm trying to define a new Polyline class which is a group of 3D points, each with a Quaternion associated, and some more data. Any sugestions on how to declare this?

Thanks in advance,
RSaint

NEW POST: Status?

RSaint — Fri, 20 Jul 2007 15:29:14 GMT

Hello Eran,

Any guidelines for the next version? OpenGl integration maybe?
I would like to help, even being a c# newbie.

regards,
Rui

NEW POST: Status?

RSaint — Fri, 20 Jul 2007 15:28:51 GMT

Hello Eran,

Any guidelines for the next version? OpenGl integration maybe?
I would like to help, even being a c# newbie.

regards,
Rui

NEW POST: Inverting matrices?

legion80 — Tue, 17 Jul 2007 16:22:08 GMT

Is there no function that easily inverts a matrix?

Source code checked in

ekampf — Sun, 01 Jul 2007 23:34:03 GMT

Initial checkin

NEW POST: Status?

ekampf — Sun, 01 Jul 2007 22:34:05 GMT

legion80 wrote:
What is the status of this project? Are improvements or bug fixes being made to the library?

Hi,
The project was closed but Im reviving it within the next few days.

REgards,
Eran

Source code checked in

ekampf — Sun, 01 Jul 2007 21:59:45 GMT

Basic project folder structure

NEW POST: Status?

legion80 — Thu, 21 Jun 2007 15:45:56 GMT

What is the status of this project? Are improvements or bug fixes being made to the library?

NEW POST: Sharp3D.Math.Geometry3D.Plane incorrect equation for _const (D)

tcreevan — Thu, 17 May 2007 21:43:33 GMT

I think I found a mistake in two of the overloaded constructors of the Sharp3D.Math.Geometry3D.Plane object. Looks like the sign on the equation of _const is wrong. For a plane the const, D, (where Ax + By + Cz + D = 0) is equal to the negative of the dot product of the normal vector and a point on the plane, i.e. n dot p = -d. The negation is missing in two of the constructors. Check out http://en.wikipedia.org/wiki/Plane(mathematics) for verification and further information on a plane.

The following are corrected constructor overloads:

// multi-line

        /// <summary>
        /// Initializes a new instance of the <see cref="Plane"/> class using given normal and a point.
        /// </summary>
        /// <param name="normal">The plane's normal vector.</param>
        /// <param name="point">A point on the plane in 3D space.</param>
        public Plane( Vector3F normal, Vector3F point )
        {
            _normal = normal;
            /*
             *                      | A |
             * Given the normal n = | B | and p as an (x,y,z) point on the plane, then d is the 
             *                      | C |
             * dot product, n dot p = -d.
             */
            _const = -Vector3F.DotProduct( normal, point );
        }
 
        /// <summary>
        /// Initializes a new instance of the <see cref="Plane"/> class using 3 given points.
        /// </summary>
        /// <param name="p0">A point on the plane in 3D space.</param>
        /// <param name="p1">A point on the plane in 3D space.</param>
        /// <param name="p2">A point on the plane in 3D space.</param>
        public Plane( Vector3F p0, Vector3F p1, Vector3F p2 )
        {
            _normal = Vector3F.CrossProduct( p1 - p0, p2 - p0 );
            _normal.Normalize( );
            /*
             *                      | A |
             * Given the normal n = | B | and p as an (x,y,z) point on the plane, then d is the 
             *                      | C |
             * dot product, n dot p = -d.
             */
            _const = -Vector3F.DotProduct( _normal, p0 );
        }

UPDATED WIKI: News Feeds

ekampf — Tue, 17 Apr 2007 01:20:32 GMT

NEWS FEED

Sharp3D.Math is moving to CodePlex

Wednesday, July 19, 2006 | From DeveloperZen.com

I just got a new project created on CodePlex.com for Sharp3D.Math.
I'll be moving all the Sharp3D.Math sources and files to that workspace within the next two days and start planning the next version using
their TFS system. I'm also looking for members to help and contribute to the project...

The workspace URL is http://www.codeplex.com/Wiki/View.aspx?ProjectName=Sharp3D

JPGL Graphics Engine

Friday, January 06, 2006 | From DeveloperZen.com

A graphics engine written in C# and OpenGL which uses Sharp3D.Math can be found at http://www.jordodesigns.com/jpgl.html.

From the web site:

JPGL is a graphics engine coded in C# using the OpenGL graphics API. The engine is partially based off the CSS450/451 graphics library, which is written in C++ and uses Direct3D. There are some major structural diversions from the CSS450/451 library, mainly to accommodate a more modular design - allowing for transparent interchangeability in three layers within the graphics engine.

The default implementation of JPGL provides an OpenGL graphics API layer. Included features are:

scene graph/node object

2D and 3D shape primitives

camera object

light objects

a GLSL shader implementation

textures

materials (with ability to load from Wavefront .MTL file)

transformation object

Wavefront .OBJ model importer

screenshot support

support for multiple OpenGL contexts

OpenGL display list caching for selected drawing

geometry data is shared between all shape primitives of same type

dynamically deformable mesh object

loft object (lofts from one profile line to another)

particle system object with OpenGL PointSprite extension support

vector, matrix, and quaternion wrappers (using Sharp3D.Math underneath)

Sharp3D.Math donations

Wednesday, June 15, 2005 | From DeveloperZen.com

I was recently asked by wout (www.woutware.com) about ways to donate money to Sharp3D.Math.
The best way for me to recieve money (without the banks taking most of it as fees) is simple by sending an amazon gift certificate to my email address which is eran *AT* ekampf.com.

Of course, all donations are welcome... ;-)

Btw, if you wish to donate code or have any other comments\questions about the project feel free to email me to the address above...

DXF Library\Viewer using Sharp3D.Math

Sunday, May 01, 2005 | From DeveloperZen.com

I got an email from Wout who is using Sharp3D.Math for his DXF class library\viewer projects.

Check his site out at http://www.woutware.com

Organizing your code

Friday, April 01, 2005 | From DeveloperZen.com

Scott Hanselman has posted a very interesting blog entry about organizing the code for software projects.

A particular interest in the post is the use of NTFS Junction points.
It could be usefull for sharing version information (take versioning out of AssemblyInfo.cs and put it in a shared file using junctions).

My own projects are organized in a rather hectic way which currently makes the process of building and releasing much more complex than it should be.

Note to self : Organize Sharp3D's code :)

It has been a while...

Tuesday, January 18, 2005 | From DeveloperZen.com

It has been a while since I last bloged and I regret that....

So whats new?

I quit my job at the IDF and applied for a position as a .NET programmer at SAP.
This means I will be also moving to my own place somewhere near SAP to avoid the long trips to\from work (now that I'll be able to afford it)

I just finished the final project at the Compilers course I am taking this semester and currently busy studying for the finals at the end of January.

I have neglected Sharp3D.Math 2.0 for a while but I plan to get back on it ASAP.
I would like to thank Wout de Zeeuw for donating 150$ for Sharp3D.Math (through Amazon.com which does not charge outrageous fees like them banks...).

On the 12.2-18.2 I plan to be on a ski vocation at Val Thorens Freestyle (everyone deserves a vocation :) )

Sharp3D.Math performance improvements

Sunday, January 09, 2005 | From DeveloperZen.com

After doing some performance tests (suggested by Wout de Zeeuw) it became clear to me that using public fields instead of properties can boost the libraries performance by 10%-20% (!!!).

Replacing the static arithmetics methods also yields another 1%-2% performance boost.

Wout has applied these changes to the latest Sharp3D.Math release and I will go over these changes and make an official Sharp3D.Math release as soon as possible after my finals are over.

I will also release a test preview of version 2.0 of the library ASAP...

Stay tuned... :)

Sharp3D.Math v1.1.3 Released

Monday, January 03, 2005 | From DeveloperZen.com

The new release contains several bug fixes.

Download the new release and check out the changes at the project's homepage.

Test Driven Development (TDD) first impressions...

Friday, December 03, 2004 | From DeveloperZen.com

Well,

I have been using TDD for Sharp3D's development process for few days now and it already helped me find several bugs.

At first I thought having to write all the tests code will just be a waste of time I could spend on adding features to the library but after some actuall work I noticed that working on the tests isn't time cosuming as I thought and it helps me find some bugs I wouldn't find otherwise and deliver a better product.

Having said that, I really have to say that the testing and refactoring capabilities in VS2005 are awsom. I only wish they would add performance testing capabilities (So I can define “test methods“ that would run and be time measured).

Oh and btw, notice the new Stopwatch class used to accuratly meaure times (for peformance etc...)

Started working on Sharp3D.Math 2.0

Friday, November 26, 2004 | From DeveloperZen.com

I started working on Sharp3D.Math v2.0 using using Visual Studio 2005 (.NET 2.0).
I am using TDD (Test Driven Development) to develop the next version to avoid bugs and make the library more efficient and usable...

Among the new features:

Better documentation.
Support for .NET 2.0 standards (Like adding TryParse in addition to Parse).
Revised code.
Better integration support. Trapezoid, Simpson, Romberg integration with accuracy\max iterations support.
Statistics.
Random and distribution dependent number generators.
3D Surfaces
2D\3D Curves
And more...

Sharp3D.Math v1.1.2.2 released!

Friday, November 26, 2004 | From DeveloperZen.com

Few minor bug fixes on this release...

Check it out on the Sharp3D.Math Project Page.

Matrix4 benchmark results - take two

Saturday, November 20, 2004 | From DeveloperZen.com

Here's an update on the report at http://www.ekampf.com/blog/PermaLink.aspx?guid=8626ee5a-3002-4e77-bfdd-e3a3f3d4a8e4.

The last test compared the generic class compiled with the new C# 2.0 compiler against the non-generic class (from the Sharp3D.Math library) compiled for .NET 1.1.

I decided to make another test were both generic and non-generic classes are in the same project and compiled for .NET 2.0.

Oddly enough, when I ran the second test on my machine the results showed that the generic class runs faster than the non generic class.
However on my friend's machine the results were more like the ones in the first test (non-generic slightly faster).

Here's the test code and executable:
Matrix4PerfTest.zip (26.94 KB)

Started working on the next major version of Sharp3D.Math

Tuesday, November 16, 2004 | From DeveloperZen.com

I started working on the next major version of Sharp3D.Math (2.0) using version 2.0 of the .NET Framework.

Some of the features I am adding:

Non-uniform real number random generetors.
Signal processing framework.
Statistics methods.
3D surfaces.
and more....

I would appreciate comments, suggestions etc...

Matrix4 benchmark results

Friday, November 12, 2004 | From DeveloperZen.com

The benchmark measured the time (in seconds) of 1,000,000 random matrix multiply operations on the different matrix implementations.
The test used the latest Sharp3D.Math build (compiled using VS2003), DirectX october update and VS2005 beta 1.

The results are:

Sharp3D.Math.Core.Matrix4F - 0.2857308100 seconds
Matrix4<float> C# Kernel - 0.3076677100 seconds
Matrix4<float> DirectX Kernel - 0.9436617200 seconds
DirectX - 0.1269457500 seconds.

As expected, the DirectX CPU optimized code runs the fastest.

I thought that using a DirectX kernel will make Matrix4<float> faster than using a C# implementation but it seems that the Matrix4<float> <--> Microsoft.DirectX.Matrix conversions are killing the performance benefits...

I expected the generic Matrix4 C# implementation to run just as fast as its non-generic counterpart but unfortunately it is slower. This is probably caused by using an interface for the kernel operations...

If anyone has an idea about how to make the conversion too\from DirectX faster and\or how to make the C# implementation just as fast as its non generic counter part I'd appreciate a comment or mail...

Moving on to Sharp3D.Math 2.0 - testing the use of generic types

Thursday, November 11, 2004 | From DeveloperZen.com

I've started doing tests on the use of generics (introduced in the new .NET framework 2.0) for the next versio of Sharp3D.Math.

Doing numerics on generic types is a bit of a problem because unconstrained type parameters are assumed to be of type System.Object which does not define arithmetic operations (like +, - etc...).
Using a constrained type parameter, the interfaces the type parameter has to implement could be defined but it is not possible to define operator constraints.

You can read a detailed discussion about the problem here and at this codeproject article.

The two suggested workarounds for this problems are:

Define an IArithmetic interface that defines the basic operations needed for math calculations (addition etc...) and use it to wrap around numeric types (float, double etc...)
Use a separated type for the operators.

The suggested workaround of using a separate type for the operators could be a good idea for Sharp3D.Math as it can also be used for platform specific performance tuning.
Say an IKernelMatrix4 implements all arithmetics for a 4x4 matrix structure, besides a native .NET implementation of IKernelMatrix4 there could also implementations using platform specific libraries such as the DirectX math library (which uses SSE optimizations for matrix arithmetics), Intel's Math Kernel library and other unmanaged optimized libraries.

Currently I am implementing a 4x4 matrix structure using the method specified above for the purpose of performance testing:
Generic matrix4x4 (.NET implementation) vs. Generic matrix4x4 (DirectX implementation) vs. Sharp3D.Math.Core.Matrix4F

I'll post the results soon...

Generic numerics with .NET

Friday, October 22, 2004 | From DeveloperZen.com

I've been playing with .NET generics trying to find a way to convert the current Sharp3D.Math structures to be generic templates.

The problem with .NET generic templates and numerics code is that there is no way to constraint a type parameter to require the existence of static method that we require for calculations (arithmetic operators etc.)

I found a very good workaround in this article.

Though I do not plan on converting Sharp3D.Math to use generics any time soon I assume I will use this solution when the time to move to .NET 2.0 comes...

Sharp3D.Math v1.1.2.1 released!

Wednesday, September 29, 2004 | From DeveloperZen.com

You can download the new release from here.
You can also check out the change log and browse the online documentation.

SEHException when serializing value types

Saturday, September 25, 2004 | From DeveloperZen.com

When implementing ISerializable the MSDN documentation recommends on applying the [SecurityPermissionAttribute(SecurityAction.Demand,SerializationFormatter=true)]
attribute on the GetObjectData method (Check out the FxCop rule).

When trying to serialize a structure with the above CAS attribute on its GetObjectData I got a nasty SEHException. When I removed the CAS attribute serialization worked fine...

I've included a test code that produces this exception with this post.
I've also sent it to Microsoft to see what's their take on this bug...

In the meanwhile I commented all the CAS attributes on the GetObjectData methods in the Sharp3D.Math library...

SerializationTest.zip (1.05 KB)

Math for 3D Game Programming & Computer Graphics

Saturday, September 18, 2004 | From DeveloperZen.com

I've been thinking about starting a tutorials series about 3D math. I could use Sharp3D.Math for code samples etc...
Anyway, I hope I'll have an update about that soon.

Sharp3D.Math v1.1.2 is released!

Saturday, September 18, 2004 | From DeveloperZen.com

You can download the new release from here.
You can also check out the change log and browse the online documentation.

NEWS FEED

UPDATED WIKI: News Feeds

ekampf — Sun, 15 Apr 2007 11:12:37 GMT

No news

NEW POST: ToString() issue

Jadzia — Sat, 07 Apr 2007 15:23:22 GMT

In Matrix3F and Matrix4F.cs you have a possible typo

For Matrix 4F this should look like:
public override string ToString()
{

StringBuilder s = new StringBuilder();
s.Append(String.Format( "|{0}, {1}, {2}, {3}|\n", _m11, _m12, _m13, _m14));
s.Append(String.Format( "|{0}, {1}, {2}, {3}|\n", _m21, _m22, _m23, _m24));
s.Append(String.Format( "|{0}, {1}, {2}, {3}|\n", _m31, _m32, _m33, _m34));
s.Append(String.Format( "|{0}, {1}, {2}, {3}|\n", _m41, _m42, _m43, _m44));

return s.ToString();
}

-----------------
You have {0}, {1}, {3}, {4} in your code :)

Oh and a wonderful lib. Keep on coding, mate.

CREATED ISSUE: Plane/Segment intersection problem

stenio — Thu, 01 Feb 2007 10:06:23 GMT

Hello, First of all thank you for this beautiful library! I'm not sure if I'm using the library in the correct way, but with the following code I get wrong results: if a segment from point A to point B intersects the plane, also the segment from B to A should intersect, but I get false from the first test. // z = 0 Plane plane = new Plane(Vector3F.ZAxis, 0); Vector3F pointA = new Vector3F(0, 0, -10); Vector3F pointB = new Vector3F(0, 0, 10); Segment segmentAB = new Segment(pointA, pointB); Segment segmentBA = new Segment(pointB, pointA); IntersectionPair intersection = IntersectionMethods.Intersects(segmentAB, plane); Console.WriteLine(intersection.IntersectionOccurred); intersection = IntersectionMethods.Intersects(segmentBA, plane); Console.WriteLine(intersection.IntersectionOccurred); Many thanks, Stenio Brunetta

User Forum: Plane/Segment intersection problem

stenio — Thu, 25 Jan 2007 17:47:44 GMT

Hello, First of all thank you for this beautiful library! I'm not sure if I'm using the library in the correct way, but with the following code I get wrong results: if a segment from point A to point B intersects the plane, also the segment from B to A should intersect, but I get false from the first test. // z = 0 Plane plane = new Plane(Vector3F.ZAxis, 0); Vector3F pointA = new Vector3F(0, 0, -1); Vector3F pointB = new Vector3F(0, 0, 1); Segment segmentAB = new Segment(pointA, pointB); Segment segmentBA = new Segment(pointB, pointA); IntersectionPair intersection = IntersectionMethods.Intersects(segmentAB, plane); Console.WriteLine(intersection.IntersectionOccurred); intersection = IntersectionMethods.Intersects(segmentBA, plane); Console.WriteLine(intersection.IntersectionOccurred); Many thanks, Stenio Brunetta

User Forum: .NET 2.0 version using generics?

Tegan — Mon, 27 Nov 2006 22:42:41 GMT

Any chance there will be a .NET 2.0 version using generics? I would love to see something like _Vector3Base which takes a float or double then using a #if subclass _VectorBase to Vector3. I think having both the float and double versions in a single DLL is a bit of code bloat that could be cleaned up very easily using generics. Are there any plans for a .NET 2.0 version using generics? If not, would you mind if I edited my version for my project to use .NET 2.0 features? I won't distribute the code (unless you want it) outside of my code package (meaning, I won't go and re-release your library with my changes).