3d Engine Collision

[JernejL]

maybe, but 1... i dont like the newton forum

RANT:

What a excellent excuse :\ you are going to ignore the original forum that has newton developers that are more qualified to answer your questions more than anyone else because you don't like it.

Helping mode:

Anyway, if you need, i can give you my newton 2.0 pascal header, i think there's one on forum from koom or sury but i am not sure, if you can't find one let me know and i'll give you mine.

does anyone had some examples of loading a mesh or so and using it with newton

creating a newton collision object from a GLSCENE mesh (newton 1.35 but will probably work with 2.0 with no changes):

 terrain:= NewtonCreateTreeCollision(nWorld, nil); 

 NewtonTreeCollisionBeginBuild(terrain);

 test:= street.MeshObjects.Items[0].ExtractTriangles(nil, nil);

 for i:= 0 to test.Count div 3 do begin
 faces[0]:= test.Items[i*3 + 0];
 faces[1]:= test.Items[i*3 + 1];
 faces[2]:= test.Items[i*3 + 2];
 NewtonTreeCollisionAddFace(terrain, 3, @faces[0], 12, 1);
 end;

 NewtonTreeCollisionEndBuild(terrain, 1);

Remember to serialize the trimesh and cache it, as it'll load much faster from serialized format.

[Memphis]

thanks, i managed to implement version 1.5(something here) which seems to work, but if there is pascal headers for version 2, i'd be happy if you can point me in the right direction. however my new problem is still related to the newton engine... i have created a box (.x) when i load the box i have created a newton collision box, which works in my engine, however i cant get the box to be right (realistic) size around the box, and if the box size changed for example, if i loaded a differ .x mesh, i thought i could use getboundingbox with directx but i can't seem to find any info as to a way to perfect that whilst also getting the size of the box to input into newton...

 ModelMan.InitModel('box.x');
 Box := TNewtonBox.Create(V3({X},{Y},{Z}), V3(10, 10, 0), 10);
 Box.Model := ModelMan.liModels[1];

so basically it renders and even drops to the ground, simulates a box dropping, but the size i dont know how to get, which is the {X, Y, Z} of the mesh.

[JernejL]

thanks, i managed to implement version 1.5(something here) which seems to work, but if there is pascal headers for version 2, i'd be happy if you can point me in the right direction. however my new problem is still related to the newton engine... i have created a box (.x) when i load the box i have created a newton collision box, which works in my engine, however i cant get the box to be right (realistic) size around the box, and if the box size changed for example, if i loaded a differ .x mesh, i thought i could use getboundingbox with directx but i can't seem to find any info as to a way to perfect that whilst also getting the size of the box to input into newton...

 ModelMan.InitModel('box.x');
 Box := TNewtonBox.Create(V3({X},{Y},{Z}), V3(10, 10, 0), 10);
 Box.Model := ModelMan.liModels[1];

so basically it renders and even drops to the ground, simulates a box dropping, but the size i dont know how to get, which is the {X, Y, Z} of the mesh.

Try calculating the AABB.

For newton 2.0 header try this header:

http://mathpudding.com/temp/Newton.pas

[Memphis]

hi thanks dude for the header.

ok yes i use

 D3DXComputeBoundingBox(@Positions[0], tModel.pMesh.GetNumVertices(), D3DXGetFVFVertexSize(tModel.pMesh.GetFVF()), tModel.minBounds, tModel.maxBounds);

this at the moment, but how would i get the size in a (x y z) format? thanks again.

[JernejL]

this at the moment, but how would i get the size in a (x y z) format? thanks again.

Just calculate the length of the aabb along each axis.

[Memphis]

for some reason D3DXComputeBoundingBox... this returns an x and z, but y is always zero... for example

D3DXComputeBoundingBox(PD3DXVector3(pVertices), tModel.pMesh.GetNumVertices(), D3DXGetFVFVertexSize(tModel.pMesh.GetFVF), tModel.minBounds, tModel.maxBounds);

gives me for min and max bounds

x,x = -0.516241977918882
y,y = 0
z,z = -0.609047940488495

[Memphis]

is there a way to draw lines around the physics box, to see the difference in actual box physic size and render size?

[JernejL]

is there a way to draw lines around the physics box, to see the difference in actual box physic size and render size?

Yes, implement newton debug rendering.

[JernejL]

Here's my version of debug rendering routines:

procedure DebugShowGeometryCollision_Wire(const body: PNewtonBody; vertexCount: integer; const FaceArray: PFloat; faceId: integer); cdecl;
var
 i: integer;
 vn: integer;

 procedure rendervertex(const num: integer);
 begin
  glVertex3fv(pointer(integer(FaceArray) + num * 12));
 end;

begin
 vn := vertexCount - 1;

 for i := 0 to vertexCount - 1 do
 begin
  rendervertex(vn);
  rendervertex(i);
  vn := i;
 end;
end;

// show rigid body collision geometry
procedure DebugShowBodyCollision_wire(const body: Pnewtonbody); cdecl;
var
 tempmatrix: TMatrix4f;
begin
 //NewtonBodyForEachPolygonDo(body, @DebugShowGeometryCollision_Wire);
 NewtonBodyGetMatrix(body, @tempmatrix);
 NewtonCollisionForEachPolygonDo(NewtonBodyGetCollision(body), @tempmatrix, @DebugShowGeometryCollision_Wire, nil);
end;

procedure NewtonWorldForEachBodyDo(const newtonWorld: PNewtonWorld; callback: PNewtonBodyIterator);
var
 thebody: PNewtonBody;
begin

 thebody := NewtonWorldGetFirstBody(newtonWorld);
 while thebody <> nil do
 begin
  callback(thebody);
  thebody := NewtonWorldGetNextBody(newtonWorld, thebody);
 end;

end;

// show all collision geometry in debug mode
procedure DebugShowCollision_wire;
begin
 NewtonWorldForEachBodyDo(nWorld, DebugShowBodyCollision_wire);
end;

and call:

 glBegin(gl_lines);
 DebugShowCollision_wire;
 glend;

[Memphis]

hi thanks, atm i have

after rending box's etc

 NewtonWorldForEachBodyDo(NewtonWorld, @DebugCallback);

procedure DebugCallback(const body : PNewtonBody); cdecl;
var
 matrix: TMatrix4f;
begin
 NewtonBodyGetMatrix(body, @matrix[0,0]);

 //i don't know how to draw the lines here with dx in 3d space.
end;

^ this being my problem, i duno how to draw the lines in 3d space with dx. i've been 'googling' for ages, checked even newton forum 3-4 times. all info i find is always opengl, and i dont understand opengl at all tbh.