Simplistic Source Example?

[3TATUK]

Can anyone link/pastebin some example code which is minimalistic in style... Not using the tutorial SDK or another framework, but just "direct" Newton functionality... Something that would make it easily portable to C.

Anything will do, but i'm specifically looking for being able to load a world geometry from triangle arrays into Newton and adding a character to collide with the world.

[JoeJ]

I assume what you want is not really possible with a few lines of code.
As far as i know applications\tutorials is also outdated, and demo sandbox might be a better reference.
It might be worth it to install Visual Studio just to look at how things should be done.

Also mesh and character is not the easiest thing to start with -
i'd suggest to use a static floor box and a dynamic box falling down and collide.
To do this, there are still a lot steps necessary:

Setup:
* Build your own BodyData struct to store your non physics information.
* Create a static (mass = 0) floor body, Collision shape, calculate mass properties with Newton, link it to your BodyData (most complex step)
* Do the same for the dynamic (mass > 0) body
* Setup ForceTorqueCallback for the dynamic body to apply gravity
Runtime:
* For now advance simulation each frame by 1/60 sec. (later sync to realtime, but keep a fixed timestep for newton)
* To render, get the bodies matrices (or use transform feedback) to render the box shapes - be sure physics and visuals match up

I can say Newton is easy to use, but the initial complexity to use any physics engine is unavoidable.
Try and ask again when there is a problem...

[Julio Jerez]

like joe said, you nee to start with a simpler example than a player.

can you compile these tutorial: ..\newton-dynamics\applications\tutorials

They were write for core 200, but if you can compile those I can go and update the to work with core 300.

[3TATUK]

But it uses all these instead of just Newton.h

#include "StdAfx.h"
#include "Entity.h"
#include "FindFloor.h"
#include "TutorialCode.h"
#include "SoundManager.h"
#include "SceneManager.h"
#include "RigidBodyUtil.h"
#include "CollisionShapeUtil.h"
#include "CollectInputAndUpdateCamera.h"

which i'm sure some need C++ and i'm looking to use C.. So i need *simplistic* stuff? Are there any? You think it's basically impossible to use Newton in C?

[Sweenie]

What about the piece of code you mentioned in the other thread?
http://newtondynamics.com/wiki/index.ph ... _C_example
That code should work, just change the NewtonCreateBody to NewtonCreateDynamicBody
The other functions in that example are valid and it seemed more that you had some missing reference or linker error.

[3TATUK]

Those references are still missing. I'm linking only libNewton.a which is all that I assume I need - but it's built with Julio's new mingw32 project files and I'm guessing it outputs a broken/corrupt lib :/

[JoeJ]

That simple c example should work indeed and is much simpler than what i suggested, and libNewton.a should contain all functions from newton.h.

Those references are still missing

Any newton function? Can you post compiler messages and your code?

[3TATUK]

Again, I think the libNewton.a created by the new mingw32 files is broken... Hopefully Julio can help test/fix them?

Code:

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#include <stdio.h>
#include <stdbool.h>
#include "Newton.h"

void   applyForceAndTorque (const NewtonBody* const body, dFloat timestep, int threadIndex)
{
   float   gravity      =   -9.8f;
   float   mass, ix, iy, iz;
   NewtonBodyGetMassMatrix(body, &mass, &ix, &iy, &iz);
   
   float   force[4]   =   { 0.0f, gravity * mass, 0.0f, 1.0f };
   NewtonBodySetForce(body, force);
}

int main (int argc, const char * argv[])
{
   float            const   initialTM[16]   =   { 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f };
   
   NewtonWorld*      const   world      =   NewtonCreate();
   NewtonCollision*   const   collision   =   NewtonCreateBox(world, 10, 10, 10, 0, NULL);
   NewtonBody*         const   body      =   NewtonCreateDynamicBody(world, collision, initialTM);
   NewtonBodySetForceAndTorqueCallback(body, applyForceAndTorque);
   NewtonBodySetMassMatrix(body, 10, 1, 1, 1);
   
   for   (int i=0; i<100; i++)
   {
      NewtonUpdate(world, 1/60);
      float   newTM[16];
      NewtonBodyGetMatrix(body, newTM);
      printf("iteration = %d, position = %f, %f, %f\n", i, newTM[12], newTM[13], newTM[14]);
   }
   
   NewtonDestroyAllBodies(world);
   NewtonDestroy(world);

   printf("Hello, World!\n");
   return 0;
}

Compile line:

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gcc -std=c99 -l:libs/newton/coreLibrary_300/projects/mingw32/libNewton.a -Ilibs/newton/coreLibrary_300/source/newton/ test.c

Output:

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C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x5a): undefined reference to `_imp__NewtonBodyGetMassMatrix'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x97): undefined reference to `_imp__NewtonBodySetForce'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x159): undefined reference to `_imp__NewtonCreate'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x19c): undefined reference to `_imp__NewtonCreateBox'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x1c7): undefined reference to `_imp__NewtonCreateDynamicBody'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x1e7): undefined reference to `_imp__NewtonBodySetForceAndTorqueCallback'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x21c): undefined reference to `_imp__NewtonBodySetMassMatrix'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x243): undefined reference to `_imp__NewtonUpdate'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x25c): undefined reference to `_imp__NewtonBodyGetMatrix'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x2b0): undefined reference to `_imp__NewtonDestroyAllBodies'
C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o:test.c:(.text+0x2c1): undefined reference to `_imp__NewtonDestroy'
d:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\DOCUME~1\ZTATIK~1\LOCALS~1\Temp\cc2PyurB.o: bad reloc address 0x20 in section `.eh_frame'
d:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: final link failed: Invalid operation
collect2.exe: error: ld returned 1 exit status

[Sweenie]

Maybe it's linking the lib as a dll instead of a static lib.
Make sure NEWTON_API isn't declared as __declspec (dllimport)
Not sure how gcc works but adding -D_NEWTON_STATIC_LIB to your compile line might work.

[3TATUK]

Cool, maybe a little better... But:

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libs/newton/coreLibrary_300/projects/mingw32/libNewton.a(Newton.o): In function `NewtonMeshSimplify':
c:\Documents and Settings\Ztatik Oh Light\Desktop\Hexer\libs\newton\coreLibrary_
300\projects\mingw32/../../source/newton/Newton.cpp:7907: undefined reference to `dgMeshEffect::CreateSimplification(int, bool (*)(float)) const'
libs/newton/coreLibrary_300/projects/mingw32/libNewton.a(dgCollisionConvexHull.o): In function `ZN21dgCollisionConvexHull6CreateEiiPKff':
c:\Documents and Settings\Ztatik Oh Light\Desktop\Hexer\libs\newton\coreLibrary_300\projects\mingw32/../../source/physics/dgCollisionConvexHull.cpp:345: undefined reference to `dgObb::SetDimensions(float const*, int, int, dgMatrix const*)'
libs/newton/coreLibrary_300/projects/mingw32/libNewton.a(dgPolyhedra.o): In function `ZNK11dgPolyhedra15CalculateSphereEPKdiPK8dgMatrix':
c:\Documents and Settings\Ztatik Oh Light\Desktop\Hexer\libs\newton\coreLibrary_300\projects\mingw32/../../source/core/dgPolyhedra.cpp:1911: undefined reference to `dgObb::SetDimensions(float const*, int, int const*, int, dgMatrix const*)'
c:\Documents and Settings\Ztatik Oh Light\Desktop\Hexer\libs\newton\coreLibrary_300\projects\mingw32/../../source/core/dgPolyhedra.cpp:1940: undefined reference to `dgObb::SetDimensions(float const*, int, int const*, int, dgMatrix const*)'
collect2.exe: error: ld returned 1 exit status

[Julio Jerez]

On these errors

c:\Documents and Settings\Ztatik Oh Light\Desktop\Hexer\libs\newton\coreLibrary_300\projects\mingw32/../../source/core/dgPolyhedra.cpp:1911: undefined reference to `dgObb::SetDimensions

the file dgObb was added recently and is missing on the make file, I added it now, please sync again

[3TATUK]

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Newton.cpp:7907: undefined reference to `dgMeshEffect::CreateSimplification(int, bool (*)(float)) const'

[Julio Jerez]

that function is there.
..\coreLibrary_300\source\meshUtil\dgMeshEffect.h
dgMeshEffect* CreateSimplification (dgInt32 maxVertexCount, dgReportProgress reportProgressCallback) const;

[3TATUK]

Okay, i fixed it by making a couple changes, first in Newton.cpp...

At the top, add:

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#include "../meshUtil/dgMeshEffect.h"

and then change line 7908 from:

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   return (NewtonMesh*) ((dgMeshEffect*) mesh)->CreateSimplification (dgInt32 (maxVertexCount), (dgReportProgress) progressReportCallback);


to:

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   return (NewtonMesh*) ((dgMeshEffect*) mesh)->CreateSimplification ((dgInt32) maxVertexCount, (dgReportProgress) progressReportCallback);


now works... So... how to create character-triangleMesh collisions? ^_^

this I guess: http://newtondynamics.com/wiki/index.ph ... _Collision