why D3DXCreateCylinder is not creating a cylinder?

问题

I am trying to make a ball trail.
rBallPos is correctly updating. Following code is not working creating a cylinder as ball's trail. How to solve it?

LPD3DXMESH /*ID3DXMesh*/ ppMeshCylinder = NULL;
hr = D3DXCreateCylinder(g_d3d_device,0.1f,0.1f,0.1f,1,1,&ppMeshCylinder,0);

hr is FAILED here also hr != D3D_OK

D3DXMATRIX cylinder, cylinder2, cylinderRotate, cylinderTrans;
D3DXMatrixRotationX(&cylinderRotate, 1.5f);
D3DXMatrixTranslation(&cylinderTrans, rBallPos.fX, rBallPos.fY, rBallPos.fZ);
D3DXMatrixMultiply(&cylinder, &cylinderRotate, &cylinderTrans);
g_d3d_device->SetTransform(D3DTS_WORLD, &cylinder);
ppMeshCylinder->DrawSubset(0);

Need help.

回答1:

You need to pass in a pointer to LPD3DXMESH, so your mesh parameter should be &ppMeshCylinder instead of ppMeshCylinder. In fact, your compiler should have already warned you.

Update: Try passing in a larger value for Slices and Stacks, say 5 or 10. It's not possible to create a cylindrical mesh with just 1 polygon.

来源：https://stackoverflow.com/questions/5583646/why-d3dxcreatecylinder-is-not-creating-a-cylinder