SDL -> DirectX 9

I'm converting a game I started in SDL over to DirectX 9 as my game will eventually contain 3D elements.
At the moment I'm working on the GUI. Each GUI element has a draw function and in SDL this simply blitted a texture onto the screen at the control's co-ordinates.
In directx I'm planning to do this with textured quads, I have a general idea on how it works but I'd like to know I'm on the right track or if there is a much better solution.

• Before calling any draw() meathod my GUI manager will call IDirect3DDevice::SetTransform to set the device to render from transformed model co-ordinates.
• Each draw function will call SetTexture to set the correct texture from an array of GUI textures.
• Then I must call SetTextureStageState for the texture (maybe this should just be called once before drawing all of the controls?)
• Then call DrawPrimitive to draw the control.

Should each control have it's own vertex buffer for storing co-ordinates?
Thanx for any advice

Use this vertex structure for your 2D GUI.

Code:

struct GUIVertex
{
  D3DXVECTOR3  Pos;
  float Rhw;
  D3DCOLOR Diffuse;
  D3DCOLOR Specular;
  float u,v;
  static const DWORD FVF;
};

Code:

const DWORD GUIVertex::FVF=D3DFVF_XYZRHW | D3DFVF_DIFFUSE | D3DFVF_SPECULAR | D3DFVF_TEX1

Create a vertex buffer with this structure. Set Pos.z to 1.0f and set x and y in SCREEN space. Just like you are drawing right to the screen. Using D3DFVF_XYZRHW will force a complete bypass of the T&L DX pipeline. Basically we are saying this vertex has already been processed so don't do any math on it.

Create your quads like this:

0........1
............
............
2.........3

For CCW:
Triangle 1 - 0,1,2
Triangle 2 - 1,3,2

For CW:
Triangle 1 - 2,1,0
Triangle 2 - 3,1,2

Texture coords should be:

0 - 0.0f,0.0f
1 - 1.0f,0.0f
2 - 0.0f,1.0f
3 - 1.0f,1.0f

To get DX to draw to your 'Window' per se without drawing outside of the boundaries of it (all drawing is clipped to the control) use

IDirect3DDevice9::SetViewPort()

Thanx Bubba I'm getting the hang of this now