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lucky6969b

Work out the view matrix for direct3d off max

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lucky6969b    1330

    CameraObject *cam = (CameraObject*) node->EvalWorldState(ip->GetTime()).obj;
            
                        Matrix3 atm = node->GetObjectTM(ip->GetTime(), 0);// 4x3 matrix
                        Matrix3 targetTM;
                        node->GetTargetTM(ip->GetTime(), targetTM);
         
                        Matrix3 matD3D;
                        Point3 p1 (1.0f, 0.0f, 0.0f);
                        Point3 p2 (0.0f, 0.0f, 1.0f);
                        Point3 p3 (0.0f, 1.0f, 0.0f);
                        Point3 p4 (0.0f, 0.0f, 0.0f);
     
                          matD3D.SetRow(0, p1);
                          matD3D.SetRow(1, p2);
                          matD3D.SetRow(2, p3);
                          matD3D.SetRow(3, p4);

                        atm = atm * matD3D;
                          targetTM = targetTM * matD3D;

                        
                        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;

                        
                        for (ki = 0; ki < 4; ki++) {
                            d3dViewXform.m[ki][2] *= -1.0f;
                       }

There must be something wrong that I can't tell.

Maybe orthogonal and perspective problem.. Any ideas?

Thanks

Jack

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lucky6969b    1330

Hello, Spiro, nice to see you again.

I have checked the result against IGameExporter

And found that the last negation part should not be there. Hence

 

    CameraObject *cam = (CameraObject*) node->EvalWorldState(ip->GetTime()).obj;
            
                        Matrix3 atm = node->GetObjectTM(ip->GetTime(), 0);// 4x3 matrix
                        Matrix3 targetTM;
                        node->GetTargetTM(ip->GetTime(), targetTM);
         
                        Matrix3 matD3D;
                        Point3 p1 (1.0f, 0.0f, 0.0f);
                        Point3 p2 (0.0f, 0.0f, 1.0f);
                        Point3 p3 (0.0f, 1.0f, 0.0f);
                        Point3 p4 (0.0f, 0.0f, 0.0f);
     
                          matD3D.SetRow(0, p1);
                          matD3D.SetRow(1, p2);
                          matD3D.SetRow(2, p3);
                          matD3D.SetRow(3, p4);

                        atm = atm * matD3D;
                          targetTM = targetTM * matD3D;

                        
                        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;

 

It seems like I have to negate the rotations in each axis and concatenate it to the translation matrix to get the final view matrix....

Edited by lucky6969b

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Seabolt    781

I'm still not entirely sure what you're trying to do with that camera, but it looks like you're trying to write a camera perspective projection matrix and it's not turning out right.

If that's the case, then MSDN has the formula you can use to create a pespective matrix: Note LH means left handed, and RH means right handed, so make sure you use the appropriate one from your coordinate space.

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lucky6969b    1330

Hey guys,

http://www.gamedev.net/topic/638823-exporting-from-pandasoft-and-3ds-max/

 

It seems like if I'd use the camera conversion method in this post, I'll get a left-handed coordinate based camera.

But I didn't check the left-handed coordinate option in pandasoft, therefore the mesh should be right-handed.

Right, got that displayed correctly though. But the y-z axis is flipped.

Because when I specify D3DXVECTOR3(10,10,0); the mesh reach the ground level.

I think it should be *better* or more consistent to convert to the left-hand. Any ideas I could solve my problem?

Thanks

Jack

Edited by lucky6969b

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Seabolt    781

Depending on the software that you export from, it may be a 'z' up coordinate system. You'll just need to rotate the matrix until it matches your coordinate system.

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lucky6969b    1330

The thing is do I rotate the mesh along with the cameras. If I do so, the cameras matrices change too.

But I will see silly renders in max while the cameras are not aligned correctly with the scene.

BTW, are we talking about rotating +90 degrees in the X axis and then -180 degrees in the Z-axis? Just to make sure it is correct.

Thanks

Jack

Edited by lucky6969b

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Seabolt    781

The final rotation depends on your handedness. And you only need to do the rotation once at load time, to get the model into the same coordinate space as the rest of your scene and your camera. So your camera should be fine.

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lucky6969b    1330

So I want to express your ideas in my own terms for my own reference.

I need to rotate the mesh in max with an angle of positive 90 degrees in the X-axis.

Then at load time, depending on whether I use OpenGL or DirectX, I rotate the mesh -180 degrees in the Z-axis, and if I use DirectX in this case

The cameras can stay fine, no need to be changed in the scene. Then the output of rendering in my application will be the same as the scene I see in max.

I should check the left-coordinate system check box in pandasoft. I can set a mesh to a location such as D3DXVECTOR3(10,10,0) and it sits on the ground level. Please let me know if there is anything missing.

Thanks seabolt, you have been great help

Jack

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lucky6969b    1330

ehhhh! the meshes are rendered correcly, my very last problem being is that the z-axis is still pointing up.

My apologizes, I have skipped the rotation of Z axis at load time, rather, I did a 90 degrees flip in the X and -180 degrees in Z.

It looks really strange in the viewport in 3ds max. But I don't really mind. But I am not accustomed to Z-axis pointing up.

sad.png

Thanks

Jack

Edited by lucky6969b

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Seabolt    781

Yeah the company I work for also has z-up coordinate systems. it drives me insane when I have to do math, and then it doesn't work because I forgot that z is up, not y haha.

Good luck though!

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