[DirectX9] Collision problem

[Ripiz]

Could you please show how to do it? I didn't really understand.

[Stucuk]

Code: Select all

Function ApplyMatrixToVec3(M : TMatrix4; V : TVec3) : TVec3;
begin
 Result[0] := ( V[0] * M[0,0] + V[1] * M[1,0] + V[2] * M[2,0] + M[3,0]);
 Result[1] := ( V[0] * M[0,1] + V[1] * M[1,1] + V[2] * M[2,1] + M[3,1]);
 Result[2] := ( V[0] * M[0,2] + V[1] * M[1,2] + V[2] * M[2,2] + M[3,2]);
end;

The above code apply's a matrix to a vertex (You should be able to convert it to C++ and DirectX). But id imagine that Direct X has a command simmiler to OpenGL's glMultiMatrix which apply's a matrix to the current world.

P.S Your still treating them as triangles which may work for most stuff, but there is bound to be instances when the polygon's are not Triangles(Such as a cylinder's top).
P.S2 Im glad i don't use DirectX, way to complex to render something which only takes about 2-5 lines in OpenGL.

[Julio Jerez]

I edit htis form teh debug display demo

#define MAX_DEBUG_LINES 2000
int debugLineCount;
dVector debugDisplayList[MAX_DEBUG_LINES][2];

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static void DebugSubmitGeometryCollision (void* userData, int vertexCount, const dFloat* faceVertec, int id)
{
   dVector p0 (faceVertec[i * 3 + 0], faceVertec[i * 3 + 1], faceVertec[i * 3 + 2]);
   for (int i = 0; (i < vertexCount) && (debugPointsCount < MAX_DEBUG_CONTACTS); i ++) {
      dVector p1 (faceVertec[i * 3 + 0], faceVertec[i * 3 + 1], faceVertec[i * 3 + 2]);
      debugDisplayList[debugLineCount][0] = p0;
      debugDisplayList[debugLineCount][1] = p1;
      debugLineCount ++;
      p0 = p1;
   }
}


static void DebugShowBodyCollision (const NewtonBody* body, void* userData)
{
   dMatrix matrix;
   NewtonBodyGetMatrix(body, &matrix[0][0]);
   NewtonCollisionForEachPolygonDo (NewtonBodyGetCollision(body), &matrix[0][0], DebugShowGeometryCollision, NULL);
}


void DebugRenderWorldCollision (const NewtonWorld* world)
{
   dVector aabbP0 (-1000.0f, -500.0f, -1000.0f);
   dVector aabbP1 (1000.0f, 500.0f, 1000.0f);

   debugLineCount = 0;
   NewtonWorldForEachBodyInAABBDo (world, &aabbP0[0], &aabbP1[0], DebugShowBodyCollision, NULL);
}

then in your render loop afte a newton update
you call

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...
DebugRenderWorldCollision (world)

// Render the array of line list usng d3d

[Ripiz]

Code: Select all

Function ApplyMatrixToVec3(M : TMatrix4; V : TVec3) : TVec3;
begin
 Result[0] := ( V[0] * M[0,0] + V[1] * M[1,0] + V[2] * M[2,0] + M[3,0]);
 Result[1] := ( V[0] * M[0,1] + V[1] * M[1,1] + V[2] * M[2,1] + M[3,1]);
 Result[2] := ( V[0] * M[0,2] + V[1] * M[1,2] + V[2] * M[2,2] + M[3,2]);
end;

I think it should be like this then

Code: Select all

void SetTransformCallback (const NewtonBody* body, const float* matrix, int threadIndex){
   Model* ent;
   Matrix mx = matrix;
   ent = (Model*)NewtonBodyGetUserData(body);
   ent->vecPos.x = matrix[12];
   ent->vecPos.y = matrix[13];
   ent->vecPos.z = matrix[14];

   Vector3 newRot(
      ent->vecRot.x*mx._11 + ent->vecRot.y*mx._21 + ent->vecRot.z*mx._31 + mx._41,
      ent->vecRot.x*mx._12 + ent->vecRot.y*mx._22 + ent->vecRot.z*mx._32 + mx._42,
      ent->vecRot.x*mx._13 + ent->vecRot.y*mx._23 + ent->vecRot.z*mx._33 + mx._43);
   ent->vecRot = newRot;
}

I did it wrong, either these maths are wrong, because object is rotating like crazy.

[Stucuk]

You can't use it like that. You need to apply the matrix to Each vertex. You can't use it as angles to rotate the object.

You may(I have never used Direct X so i can't be sure) be able to use D3DXMatrixMultiply with the matrix newton gives you instead of manualy applying the matrix to each vertex.

[Carli]

I did it wrong, either these maths are wrong, because object is rotating like crazy.

DX is a left-handed system, GL a right-handed.
Try to swap each m_ab to m_ba (transpose the matrix)