Question

I am currently working on a project where I need to create a server/client application which draws a graphic in two separate application windows using C++, DirectX & Winsock. The image should translate across the x axis of the server app window until it begins to disappear from view on the right hand side. As it disappears from view, the client application should then render the image & translate it across its own screen, giving the impression of the image moving across from server window to client window.

I am not looking for any completed code here, but rather indicators on how I could go about informing the client app to begin rendering the image again on its screen when the image has completed its translation cycle across the server application window. I am thinking I can do something centered around tracking the location of g_Rectx in the code below, and informing the client app via a message sent via winsock to begin rendering & trnslating when the x coordinate goes out of view on the server app, but am unsure how to achieve this.

Currently, I have an image displaying in the server window & translating across the window using the standard matrix translation technique, this all works fine. It is how to inform the client application when to start rendering on its side which I am unsure how to implement.

Any thoughts on how I could go about doing this would be much appreciated.

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excerpt from current translation code in case this helps…

            // translation matrix to move the image along x axis
    D3DXMATRIX TranslateMatrix;
    D3DXMatrixTranslation(&TranslateMatrix, g_RectX, g_RectY, g_RectZ);
    g_pd3dDevice -> SetTransform(D3DTS_WORLD, &TranslateMatrix);

    // Update the rectangle's x co-ordinate
    g_RectX += 0.1f;

Answer 1

It looks to me like you simply want to propagate the transformation of your object (position, orientation, scale) and have two different views, one for the server, one for the client. These views can simply be different camera positions. When the object moves in the world on the server, it will move on the client as well. For a given distance between your object and the server’s camera, you should be able to compute when it will start touching the edge of the view frustum… and from there you could deduce the required camera position on the client to have a “flow” from one screen to another.