How do I swap Y and Z axis with D3DXMATRIX?

Jack Luk · 2013-02-24T10:16:58

I seem to be having problem exporting camera with 3ds max. The object is sitting horizontally in max, now the exported object is standing upright in dx9 I believe the y-z axis is wrong. How do I flip it around? I mean what matrix can I multiply with this wrong matrix? /// float mat[4][4]; Matrix3 invTM; int persp; float hither; float yon; D3DXMATRIX m_d3dWorldXform; // your app world transform matrix D3DXMATRIX m_d3dViewXform; // your app view transform matrix D3DXMATRIX m_d3dProjXform; // your app projection transform matrix Interface *ip2 = GetCOREInterface(); ViewExp * pView = ip2->GetActiveViewport(); // Get the viewport in question GraphicsWindow *gw = pView->getGW(); // Get the GraphicsWindow context gw->getCameraMatrix( mat, &invTM, &persp, &hither, &yon); // getting these values to work with ... see above for their types float oneOverDepth = 1.0f / (yon - hither); // Set the Direct3D Camera View Position and Camera Projection Transforms. // // The first matrix is the full projection transformation matrix that // converts World Coordinates into NPC. This means that the matrix is the // product of the Camera View Position transformation matrix and the Camera // Projection matrix. The second matrix is the inverse of the Camera View // Position transformation matrix so if we multiply this second matrix by // the first, we get the Camera Projection matrix. If we take the inverse // of the second matrix, we get the Camera View Position matrix. // // The Camera View Position transformation converts World coordinates into // Camera View Position coordinates where the camera is located at the // origin. We have been given the inverse of the Camera View Position // matrix so the first step is to take the inverse of this transform to // obtain the Camera View Position matrix. // General conversion from 3ds max coords to Direct3D coords: // // 3ds max: (Up, Front, Right) == (+Z, +Y, +X) // // Direct3D: (Up, Front, Right) == (+Y, +Z, +X) // // Conversion from 3ds max to Direct3D coords: // // 3ds max * conversion matrix = Direct3D // // [ x y z w ] * | +1 0 0 0 | = [ X Y Z W ] // | 0 0 +1 0 | // | 0 +1 0 0 | // | 0 0 0 +1 | // // The View transform below accomplishes this. The standard View transform // received makes the rotation about the X axis because the assumption was // to transform to RH coords with the XY plane being the vertical plane // instead of the XZ plane. The negation of the the Z column does the RH // to LH flip. Thus, the View transform makes the transition from RH 3ds // max coords to LH Direct3D coords. Matrix3 camTM = Inverse(invTM); // We now have an affine matrix (4x3) with no perspective column (it is // understood to be (0, 0, 0, 1)). We add the fourth column and flip the // Z-axis because Direct3D uses a left-handed coordinate system and MAX // uses a right-handed coordinate system. // Copy the affine view matrix data int ki, kj; MRow *pcvm = camTM.GetAddr(); for (ki = 0; ki < 4; ki++) { for (kj = 0; kj < 3; kj++) { m_d3dViewXform.m[ki][kj] = pcvm[ki][kj]; } } // Assign the fourth column (perspective terms) m_d3dViewXform.m[0][3] = m_d3dViewXform.m[1][3] = m_d3dViewXform.m[2][3] = 0.0f; m_d3dViewXform.m[3][3] = 1.0f; // Scale the Z-axis (third column) by -1 to flip to left-handed Direct3D // coordinate system for (ki = 0; ki < 4; ki++) { m_d3dViewXform.m[ki][2] *= -1.0f; } // Calculate the Direct3D Camera Projection transformation matrix. // // First, multiply the MAX full projection matrix by the inverse of the MAX // Camera View Position matrix to obtain the MAX Camera Projection matrix. // // This gives us a correct Direct3D Camera Projection matrix except for the // lower right quadrant. // MRow *pa = invTM.GetAddr(); for (ki = 0; ki < 4; ki++) { float val = (float)(ki==3); for (kj = 0; kj < 4; kj++) { m_d3dProjXform.m[ki][kj] = pa[ki][0] * mat[0][kj] + pa[ki][1] * mat[1][kj] + pa[ki][2] * mat[2][kj] + val * mat[3][kj]; } } // Now calculate the lower right quadrant of the Camera Projection matrix // using the facts that MAX uses an NPC Z-axis range of +1 to -1 whereas // Direct3D uses an NPC Z-axis range of zero to +1. // // For ease of reference, the general forms of the Direct3D Projection // matrix for perspective and orthographic projections are given below. // // Please note that the matrices are specified in row-major order. This // means that the translate terms are located in the fourth row and the // projection terms in the fourth column. This is consistent with the way // MAX, Direct3D, and OpenGL all handle matrices. Even though the OpenGL // documentation is in column-major form, the OpenGL code is designed to // handle matrix operations in row-major form. if (persp) { // Perspective projection. The general form of the Direct3D Camera // Projection matrix is: // // | 2n/(r-l) 0 0 0 | // | 0 2n/(t-b) 0 0 | // | (r+l)/(r-l) (t+b)/(t-b) f/(f-n) 1 | // | 0 0 -fn/(f-n) 0 | // // Construct the lower right four terms correctly for Direct3D. // m_d3dProjXform.m[2][2] = yon*oneOverDepth; m_d3dProjXform.m[2][3] = 1.0f; m_d3dProjXform.m[3][2] = -(yon*hither*oneOverDepth); m_d3dProjXform.m[3][3] = 0.0f; } else { // Orthographic projection. The general form of the Direct3D Camera // Projection matrix is: // // | 2/(r-l) 0 0 0 | // | 0 2/(t-b) 0 0 | // | 0 0 1/(f-n) 0 | // | (r+l)/(r-l) (t+b)/(t-b) -n/(f-n) 1 | // // Construct the lower right four terms correctly for Direct3D. // m_d3dProjXform.m[2][2] = oneOverDepth; m_d3dProjXform.m[2][3] = 0.0f; m_d3dProjXform.m[3][2] = -(hither*oneOverDepth); m_d3dProjXform.m[3][3] = 1.0f; } Thanks Jack

Graphics and GPU Programming Programming OpenGL

Started by lucky6969b August 09, 2012 04:10 AM

9 comments, last by lucky6969b 11 years, 1 month ago

lucky6969b

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Author

February 24, 2013 10:16 AM

Hello eppo,


                       CameraObject *cam = (CameraObject*) node->EvalWorldState(ip->GetTime()).obj;
            
                        Matrix3 atm = node->GetObjectTM(ip->GetTime(), 0);// 4x3 matrix
             
                        int ki, kj;
                        MRow *pcvm = atm.GetAddr();        
                        for (ki = 0; ki < 4; ki++) {
                            for (kj = 0; kj < 3; kj++) {
                                d3dViewXform.m[ki][kj] = pcvm[ki][kj];
                            }
                        }
                        // Assign the fourth column (perspective terms)

                        d3dViewXform.m[0][3] = d3dViewXform.m[1][3] = d3dViewXform.m[2][3] = 0.0f;
                        d3dViewXform.m[3][3] = 1.0f;


                        D3DXMATRIX matrixPitch, matrixScale;

                        D3DXMatrixIdentity(&matrixPitch);
                        D3DXMatrixIdentity(&matrixScale);

                        D3DXMatrixRotationYawPitchRoll(&matrixPitch, 0.f, PI * .5f, 0.f);
                        D3DXMatrixScaling(&matrixScale, 1.f, 1.f, -1.f);

                        d3dViewXform = matrixPitch * matrixScale * d3dViewXform;

The camera still got distorted. I evaluated this thread again because I want +y to go upward and +z go outward.

Thanks

Jack

How do I swap Y and Z axis with D3DXMATRIX?

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How do I swap Y and Z axis with D3DXMATRIX?

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