Hi, I have just begun to learn DirectX 9 but i have one strange problem. I'm writting 2D GUI and I'm using D3DXMatrixOrthoOffCenterLH function. But when i resize my window, primitives goes blurred. Look at the screen: before resize window (640x480, quad 300x300): http://img17.imageshack.us/img17/3995/82108813.jpg after: http://img705.imageshack.us/img705/3149/51572795.jpg I'm using DrawPrimitiveUP(D3DPT_TRIANGLEFAN) and D3DPT_LINESTRIP functions. There is any chance to fix it cuz I need straight lines not blurred? :/

Thank you, now all is working properly. I just Reset() device after window resize :)