better collisions?

[RadSun]

Hi
With the examples i created a simple model with 3rd camera. But the collisions are not very good. Model is blocking sometimes. and i hace two another problems but its easyer to show

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scene::ISceneNodeAnimator * anim = smgr->createCollisionResponseAnimator(selector,hero, vector3df(25,25,25),core::vector3df(0,-1,0),core::vector3df(0,0,0));
hero->addAnimator(anim);
anim->drop();

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if (key_left==1)
		{ direction-=2; hero->setRotation(core::vector3df(0,direction,0));}
if (key_right==1)
		{ direction+=2; hero->setRotation(core::vector3df(0,direction,0));}
if (key_up==1)
		{
			core::vector3df v = hero->getPosition();
			v.X += sin(degtorad(dir))*5;
			v.Z += cos(degtorad(dir))*5;

			hero->setPosition(v);
		}

[Acki]

If you want a better collision you should use a good physics engine, like Newton !!!

The collision system of Irrlicht is basic and not really good...

[RadSun]

Can you give me link to toutrial/example for Irrlicht&Newton? I found on site but its for Irrlict 0.6

[Acki]

Well, I think you wont fine an up to date tutorial for Newton + Irrlicht, because Irrlicht is growing preaty fast with many changes...

I think best would be to take an out of date tutorial and try to adapt it to the newer Irrlicht version...

Their are other physics engines, too...
ODE, Tokamak and PhysX, for example...
But I prefere Newton, it is really versatile and has many features like ragdolls and cars, and you can define materials and such for each collision shape...

[RadSun]

I getting error

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e:\irrlicht-1.3.1\marshinto\game.cpp(92) : error C2248: 'irr::core::CMatrix4<T>::M' : cannot access private member declared in class 'irr::core::CMatrix4<T>'
        with
        [
            T=irr::f32
        ]
        e:\irrlicht-1.3.1\include\matrix4.h(275) : see declaration of 'irr::core::CMatrix4<T>::M'
        with
        [
            T=irr::f32
        ]

in this:

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void _cdecl CGame::SetMeshTransformEvent(const NewtonBody* body, const float* matrix)
{
	// copy the matrix into an irrlicht matrix4
	matrix4 mat;
	memcpy(mat.M, matrix, sizeof(float)*16);

	// Retreive the user data attached to the newton body
	ISceneNode *tmp = (ISceneNode *)NewtonBodyGetUserData(body);
	if (tmp)
	{
		// Position the node
		tmp->setPosition(mat.getTranslation());		// set position
		tmp->setRotation(mat.getRotationDegrees());	// and rotation
	}
}

[Perceval]

Replace mat.M by mat.pointer()

[Acki]

if you do what your compiler told you:

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see declaration of 'irr::core::CMatrix4<T>::M'

you'll see that matrix4 needs a template...
this is since Irrlicht 1.3 !!!
I'm using Irrlicht v1.2 and there it's like you did...
So I'm not sure, but try it like this:

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matrix4<float> mat;

[hybrid]

No, matrix4 is still a proper type for a float matrix4. CMatrix4 is the template. So it's still ok, just as before. Perceval is completely right.

[RadSun]

Thanks, now its work.
But i have two warnings:

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e:\irrlicht-1.3.1\marshinto\game.cpp(44) : warning C4018: '<' : signed/unsigned mismatch
e:\irrlicht-1.3.1\marshinto\game.cpp(52) : warning C4018: '<' : signed/unsigned mismatch

in this:

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for (cMeshBuffer=0; cMeshBuffer<g_map->getMesh(0)->getMeshBufferCount(); cMeshBuffer++)

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for (j=0; j<mb->getIndexCount(); j+=3)

It compile and run but than it show error "Unhandled exception..."

[RadSun]

This is code from toutrial for Newton&irrlicht v.6. Do soeone now how to make its work in 1.3.1??

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g_newtonmap = NewtonCreateTreeCollision(nWorld, NULL);
	NewtonTreeCollisionBeginBuild(g_newtonmap);
	int cMeshBuffer, j;
	int v1i, v2i, v3i;
	IMeshBuffer *mb;

	float vArray[9]; // vertex array (3*3 floats)

	int tmpCount = 0;

	for (cMeshBuffer=0; cMeshBuffer<g_map->getMesh(0)->getMeshBufferCount(); cMeshBuffer++)
	{	
		mb = g_map->getMesh(0)->getMeshBuffer(cMeshBuffer);

		video::S3DVertex2TCoords* mb_vertices = (irr::video::S3DVertex2TCoords*)mb->getVertices();

		u16* mb_indices  = mb->getIndices();

		// add each triangle from the mesh
		for (j=0; j<mb->getIndexCount(); j+=3)
		{
			v1i = mb_indices[j];
			v2i = mb_indices[j+1];
			v3i = mb_indices[j+2];
	
			vArray[0] = mb_vertices[v1i].Pos.X;
			vArray[1] = mb_vertices[v1i].Pos.Y;
			vArray[2] = mb_vertices[v1i].Pos.Z;
			vArray[3] = mb_vertices[v2i].Pos.X;
			vArray[4] = mb_vertices[v2i].Pos.Y;
			vArray[5] = mb_vertices[v2i].Pos.Z;
			vArray[6] = mb_vertices[v3i].Pos.X;
			vArray[7] = mb_vertices[v3i].Pos.Y;
			vArray[8] = mb_vertices[v3i].Pos.Z;

			NewtonTreeCollisionAddFace(g_newtonmap, 3, (float*)vArray, 12, 1);
		}

	}
	NewtonTreeCollisionEndBuild(g_newtonmap, 0);
	g_newtonmapbody = NewtonCreateBody(nWorld, g_newtonmap);

[vitek]

Not all mesh buffers use the 2TCoords vertex type. The following _should_ work a little better. I'm not absolutely sure it will compile because I don't have a compiler on this PC and I don't use Newton.

Travis

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template <typename VertexType, typename IndexType>
void CreateCollisionTree_AddFaces(NewtonCollision* tree, const scene::IMeshBuffer* const mb)
{
    const VertexType* const vertices = (const VertexType*)mb->getVertices();
    const IndexType * const indices  = (const IndexType *)mb->getIndices(); 

    u32 j;
    for (j = 0; j < mb->getIndexCount(); j += 3) 
    { 
      const IndexType i1 = indices[j+0]; 
      const IndexType i2 = indices[j+1]; 
      const IndexType i3 = indices[j+2];

      f32 floats[9];
    
      floats[0] = vertices[i1].Pos.X; 
      floats[1] = vertices[i1].Pos.Y; 
      floats[2] = vertices[i1].Pos.Z; 

      floats[3] = vertices[i2].Pos.X; 
      floats[4] = vertices[i2].Pos.Y; 
      floats[5] = vertices[i2].Pos.Z;
 
      floats[6] = vertices[i3].Pos.X; 
      floats[7] = vertices[i3].Pos.Y; 
      floats[8] = vertices[i3].Pos.Z; 

      NewtonTreeCollisionAddFace(tree, 3, floats, 3 * sizeof(f32), 1); 
   }
}

NewtonCollision* CreateCollisionTree(NewtonWorld* nWorld, const scene::IMesh* const mesh) 
{
   NewtonCollision* tree = NewtonCreateTreeCollision(nWorld, NULL); 
   NewtonTreeCollisionBeginBuild(tree); 

   u32 j;
   for (j = 0; j < mesh->getMeshBufferCount(); ++j) 
   {    
      const scene::IMeshBuffer* const mb = mesh->getMeshBuffer(j);

      switch (mb->getVertexType())
      {
      case video::EVT_STANDARD:
        CreateCollisionTree_AddFaces<video::S3DVertex, u16>(tree, mb);
        break;
      case video::EVT_2TCOORDS:
        CreateCollisionTree_AddFaces<video::S3DVertex2TCoords, u16>(tree, mb);
        break;
      case video::EVT_TANGENTS:
        CreateCollisionTree_AddFaces<video::S3DVertexTangents, u16>(tree, mb);
        break;
      default:
        // unexpected vertex type!
        break;
      }
   } 

   NewtonTreeCollisionEndBuild(tree, 1);

   return tree;
}