3d Engine Collision

[chronozphere]

I think this will interest you:

http://msdn.microsoft.com/en-us/libr...91(VS.85).aspx

Take a look at LineLists and LineStrips. It shows you how to draw lines by using vertexbuffers and a DrawPrimitive call.

Hope it helps.

[Memphis]

is already late, 4.29am.. almost falling asleep

but anyways

procedure Polycallback(const body: PNewtonBody; vertexCount: Integer; const FaceArray: PFloat; faceId: Integer); cdecl;
var
 i: Integer;
 p01: array[0..1] of TD3DXVector3;
begin
 i := vertexCount - 1;
 p01[0] := D3DXVector3( PSingle(Cardinal(FaceArray) + i * 3 )^, PSingle(Cardinal(FaceArray) + i * 3 + 1 )^, PSingle(Cardinal(FaceArray) + i * 3 + 2)^);

 for i := 0 to vertexCount-1 do begin
  p01[1] := D3DXVector3( PSingle(Cardinal(FaceArray) + i * 3 )^, PSingle(Cardinal(FaceArray) + i * 3 + 1 )^, PSingle(Cardinal(FaceArray) + i * 3 + 2)^);

  Engine.ResMan.DX_Device.DrawPrimitiveUP(D3DPT_LINELIST, 1, p01, SizeOf(TD3DXVector3));

  p01[0] := p01[1];
 end;
end;

procedure DebugCallback(const body : PNewtonBody); cdecl;
begin
 NewtonBodyForEachPolygonDo(body, @Polycallback);
end;

this is what i've tried but i can't get it to work, all lines all over the place... lol

[Memphis]

ok i've now wrote an extra proc for testing..

procedure DrawLine(x1, y1, z1: Single; x2, y2, z2: Single);
type
 TVertex = record
  x: Single;
  y: Single;
  z: Single;
  color: DWord;
  tu: Single;
  tv: Single;
 end;
var
 triData: array[1..2] of TVertex;

 procedure SetVertex(ver: TVertex; _x,_y,_z: Single; _col: DWord; _tu, _tv: Single);
 begin
  with ver do begin
   x := _x; y := _y; z := _z;
   color := _col;
   tu := _tu; tv := _tv;
  end;
 end;
begin
 SetVertex(triData[1], x1, y1, z1, $FFFFFF, 0, 0);
 SetVertex(triData[2], x2, y2, z2, $FFFFFF, 0, 0);

 Engine.ResMan.DX_Device.DrawPrimitiveUP(D3DPT_LINELIST, 1, triData, SizeOf(TVertex));
end;

procedure Polycallback(const body: PNewtonBody; vertexCount: Integer; const FaceArray: PFloat; faceId: Integer); cdecl;
var
 i: Integer;
 p0, p1: TD3DXVector3;
 pList: array of TD3DXVector3;
begin
 SetLength(pList, vertexCount);
 CopyMemory(pList, FaceArray, vertexCount * SizeOf(TD3DXVector3));

 p0 := pList[0];
 for i := 1 to VertexCount - 1 do begin
  p1 := pList[i];

  DrawLine(p0.x, p0.y, p0.z, p1.x, p1.y, p1.z);
  p0 := p1;
 end;
end;

procedure DebugCallback(const body : PNewtonBody); cdecl;
begin
 NewtonBodyForEachPolygonDo(body, @Polycallback);
end;

so this is what im doing now, but this draws a point in the sky, as the boxes fall lines are drawn towards the box... i just cant work it out...

[VilleK]

One thing you should to is change SetVertex:

SetVertex(var ver: TVertex; ...

Otherwise it is only modifying a copy of the record.

[Memphis]

ah damn i didnt realise i did that, thanks very much for spotting that, that has kind of fixed it, now i see a cube, but it is drawn no where near my actual cube lol

here is example....

Download Here

[Memphis]

ok i think i have solved it, i forgot to - the matrix

  DrawLine(matrix._41-p0.x, matrix._42-p0.y, matrix._43-p0.z, matrix._41-p1.x, matrix._42-p1.y, matrix._43-p1.z);

so now this is sorted, the actual physical cube is drawn different to the rendered .x model... also the physics cube goes slighty through the ground/grass



Sample Here

[JernejL]

Draw the debug geometry with no transformation (original plain world matrix).

[Memphis]

sorry i dont understand.

after rendering my land i do

 for v := Low(boxs) to High(boxs) do begin
 //for v := 1 to 1 do begin
  boxs[v].Render;
  DebugCallback(boxs[v].NewtonBody);
 end;

 NewtonUpdate(NewtonWorld, PerfCount.DeltaTime);

procedure TNewtonBox.Render;
var
 v: Integer;
 matWorld: TD3DMatrix;
begin
 NewtonBodyGetMatrix(NewtonBody, @matWorld.m[0,0]);
 Engine.ResMan.DX_Device.SetTransform(D3DTS_WORLD, matWorld);

 v := 0;
 while (v < Model.NumMaterials) do begin
  // Set the material and texture for this subset
  Engine.ResMan.DX_Device.SetMaterial(Model.pMeshMaterials[v]);
  Engine.ResMan.DX_Device.SetTexture(0, Model.pMeshTextures[v]);

  // Draw the mesh subset
  Model.pMesh.DrawSubset(v);

  Inc(v);
 end;
end;

[Memphis]

ok i found what the problem was, the model (.x) had to be centered... so what i mean is...

if the model is 1, 1, 1 in 3dsmax

i had to move the z co-ordinate to -0.5 why is this? and is there a way to set the mesh even if it has not been centered in 3ds max?

thanks in advance.

---

another problem.. on my computer. the box's drop at a steady rate, on my wifes laptop, they drop very fast and even bounce.

which looks like it has something todo with newton update? when my FPS is low they drop fast. when it is high, they drop slow.

[JernejL]

ok i found what the problem was, the model (.x) had to be centered... so what i mean is...

if the model is 1, 1, 1 in 3dsmax

i had to move the z co-ordinate to -0.5 why is this? and is there a way to set the mesh even if it has not been centered in 3ds max?

thanks in advance.

---

another problem.. on my computer. the box's drop at a steady rate, on my wifes laptop, they drop very fast and even bounce.

which looks like it has something todo with newton update? when my FPS is low they drop fast. when it is high, they drop slow.

1. mesh may be transformed by a matrix or by vertices.

2. you are sending fixed update time with a dynamic fps simulation.. send the proper deltatime to newton!