Contents  Getting Started  Setting Up  Drawing & Texturing  Wrapping Up  Printable version  Discuss this article  in the forums

Background

I have been reading alot of questions lately related to DirectX 8 and the exclusion of DirectDraw from the new API. Many people have fallen back to DX7. I can understand people using DX7 if they have alot of experience with that API, but many of the questions seem to be coming from people who are just learning DX, and they are stuck learning an old API. People have argued that many people don't have 3D hardware, and therefore D3D would be a bad alternative for DirectDraw. I don't believe this is true - 2D rendering in D3D requires very little vertex manipulation, and everything else boils down to fillrate. In short, 2D rendering in D3D on 2D hardware should have pretty much the same performance as DirectDraw, assuming decent fillrate. The advantage is that the programmer can learn the newest API, and performance on newer hardware should be very good. This article will present a framework for 2D rendering in DX8 to ease the transition from DirectDraw to Direct3D. In each section, you may see things that you don't like ("I'm a 2D programmer, I don't care about vertices!"). Rest assured, if you implement this simple framework once, you'll never think about these things again.

Getting Started

Assuming you have the DX8 SDK, there are a couple tutorials that present how to create a D3D device and set up a render loop, so I don't want to spend alot of time on that. For the purposes of this article, I'll talk about the tutorial found in [DX8SDK]\samples\Multimedia\Direct3D\Tutorials\Tut01_CreateDevice, although you can add it to anything. To that sample, I'll add the following functions:

void PostInitialize(float WindowWidth, float WindowHeight) - this function is called by the app after everything else is set up. You've created your device and initialized everything. If you're following along with the Tutorial code, WinMain looks like this:

...
if( SUCCEEDED( InitD3D( hWnd ) ) )
    { 
        PostInitialize(200.0f, 200.0f);  // This is my added line. The values of
                                         // 200.0f were chosen based on the sizes
                                         // used in the call to CreateWindow.

        ShowWindow( hWnd, SW_SHOWDEFAULT );
...

void Render2D() - This function is called each time you want to render your scene. Again, the Render function of the Tutorial now looks like this:

VOID Render()
{
    if( NULL == g_pd3dDevice )
        return;

    // Clear the backbuffer to a blue color
    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );
    
    // Begin the scene
    g_pd3dDevice->BeginScene();
    
    Render2D(); //My added line...
    
    // End the scene
    g_pd3dDevice->EndScene();
    
    // Present the backbuffer contents to the display
    g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}

OK, that's our shell of an application. Now for the good stuff...

Next : Setting Up