如何在DirectX 9中设置左上角坐标？

Question

I need to draw something in DirectX 9. I am interested to work in a way that the coordinates will be adjusted to pixels, while (0,0) will be the TopLeft corner. Here is what I do:

RECT clientRect;
::GetClientRect(m_hWIN, &clientRect);

D3DXMATRIX matOrtho2D, matIdentity;    

D3DXMatrixOrthoOffCenterLH(&matOrtho2D, 0, clientRect.right, 0, clientRect.bottom, 0.0f, 1.0f);
D3DXMatrixIdentity(&matIdentity);

g_pDirect3D_Device->SetTransform(D3DTS_PROJECTION, &matOrtho2D);
g_pDirect3D_Device->SetTransform(D3DTS_WORLD, &matIdentity);
g_pDirect3D_Device->SetTransform(D3DTS_VIEW, &matIdentity);

This works fine, except the (0,0) is the BottomLeft corner. How can I change it? Thanks!

Answer 1

This should be add to code:

D3DXMATRIX matTranslate, matFlip;  

D3DXMatrixTranslation(&matTranslate, 0, clientRect.bottom, 0.0f);
D3DXMatrixRotationX(&matFlip, D3DXToRadian(180));
D3DXMATRIX matCoordTransform = matFlip * matTranslate;

g_pDirect3D_Device->SetTransform(D3DTS_WORLD, &matCoordTransform);