. To use the D3DX functions, we need to add:
>#include
and add d3dx8dt.lib to the list of linked libraries. Once that was set up, the PostInitialize function now looks like this:
>void PostInitialize(float WindowWidth, float WindowHeight) {
> D3DXMATRIX Ortho2D;
> D3DXMATRIX Identity;
> D3DXMatrixOrthoLH(&Ortho2D, WindowWidth, WindowHeight, 0.0f, 1.0f);
> D3DXMatrixIdentity(&Identity);
> g_pd3dDevice->SetTransform(D3DTS_PROJECTION, &Ortho2D);
> g_pd3dDevice->SetTransform(D3DTS_WORLD, &Identity);
> g_pd3dDevice->SetTransform(D3DTS_VIEW, &Identity);
>}
We are now set up for 2D drawing, now we need something to draw. The way things are set up, our drawing area goes from —WindowWidth/2 to WindowWidth/2 and -WindowHeight/2 to WindowHeight/2. One thing to note, in this code, the width and the height are being specified in pixels. This allows us to think about everything in terms of pixels, but we could have set the width and height to say 1.0 and that would have allowed us to specify sizes, etc. in terms of percentages of the screen space, which would be nice for supporting multiple resolutions easily. Changing the matrix allows for all sorts of neat things, but for simplicity, we'll talk about pixels for nowЕ Setting Up a 2D "Panel"
When I draw in 2D, I have a class called CDX8Panel that encapsulates everything I need to draw a 2D rectangle. For simplicity, and it avoid a C++ explanation, I have pulled out the code here. However, as we build up our code to draw a panel, you'll probably see the value of such a class or higher level API if you don't use C++. Also, we are about to recreate much that goes on in the ID3DXSprite interface. I'm explaining the basics here to show the way things work, but you may want to use the sprite interface if it suits your needs.
My definition of a panel is simply a 2D textured rectangle that we are going to draw on the screen. Drawing a panel will be extremely similar to a 2D blit. Experienced 2D programmers may think that this is a lot of work for a blit, but that work pays off with the amount of special effects that it enables. First, we have to think about the geometry of our rectangle. This involves thinking about vertices. If you have 3D hardware, the hardware will process these vertices extremely quickly. If you have 2D hardware, we are talking about so few vertices that they will be processed very quickly by the CPU. First, let's define our vertex format. Place the following code near the #includes:
>struct PANELVERTEX {
> FLOAT x, y, z;
> DWORD color;