If you mean that you went from using a 2-d orthographic projection matrix to using a 3-d perspective projection matrix, then you are going to have to think in terms of a view frustum. Because the virtual world your camera is looking at is now 3-d dimensional along the z-axis, the width of the horizon is now specified in world coordinates, not simply 0..599 like in 2-d.

Can you give more details about your projection matrix and what you are trying to accomplish?

I'm in the process of making a 2d game, and have made a transition from using d3d's 2D scene to just using 3d quads, however this is giving me a bit of issues with mouse control. While yes the mouse position is indeed moving in the direction I am moving my mouse physically, it is moving at a different rate. I am wandering how one would deal with this? my screen is 800/600 and my view transform matrix is 600 units away on the z axis, looking at everything from a distance.

ThePointingMan, on 04 Apr 2013 - 03:50, said:

Steve_Segreto, on 04 Apr 2013 - 03:15, said:
If you mean that you went from using a 2-d orthographic projection matrix to using a 3-d perspective projection matrix, then you are going to have to think in terms of a view frustum. Because the virtual world your camera is looking at is now 3-d dimensional along the z-axis, the width of the horizon is now specified in world coordinates, not simply 0..599 like in 2-d.

Can you give more details about your projection matrix and what you are trying to accomplish?

1So these are the Matrices I have set up for my camera.

 D3DXMatrixLookAtLH(&mCamera,	
    &D3DXVECTOR3 (0, 0, 600),    // the camera position
    &D3DXVECTOR3 (0, 0, 0.0f),      // the look-at position
    &D3DXVECTOR3 (0.0f, -1.0f, 0.0f));    // the up direction

	D3DXMatrixPerspectiveFovLH(&mLense,
                               D3DXToRadian(45),//Field of view
                               _w / _h,//dimensions or somethin
                               1.0f,    // the near view-plane
                               1000.0f);    // the far view-plane

// set the view transform
d3ddev->SetTransform(D3DTS_VIEW, &(camera->GetCamera()));

// set the projection transform
d3ddev->SetTransform(D3DTS_PROJECTION, &(camera->GetLense()));

What I'm doing is creating a level editing program for a game I am making, there is a grid on the screen and I wish to make it so that when I click on one of the tiles it changes to the type of tile i have selected. I have just been using the getcursorpos() and screentoclient() to find the mouse position, but since this isn't a flat 2d program those co-ordinates aren't lining up with what I see on screen.

  Matrix View = GetViewMatrix(); //Get our view matrix(your lookat function might return this, or it might directly set the matrix to the gpu?)
  Matrix Perspective = GetPerspectiveMatrix(); //Get our perspective matrix.
  Vector2 MouseScreen = GetMouseScreenCoordinates(); //Get the screen coordinates that are relative to the window.
  Vector3 WorldNear = UnProject(MouseScreen.X, MouseScreen.Y, 0.0f, View, Perspective); //We get the world coordinates that are at the camera's near plane.
  Vector3 WorldFar = UnProject(MouseScreen.X, MouseScreen.Y, 1.0f, View, Perspective); //We get the world coordinates that are at the camera's far plane.
  //Since the game tile's world position z-depth is at 0(note that the camera is at 600, but the object's are at 0 on the z-axis(or so i assume anyway)).
  //We basically have a ray from the front of the camera, to the back of the camera, now we just need to get the point on the plane that the game is on:
  Vector3 WorldDir = WorldFar-WorldNear;
  float D = WorldNear.Z/WorldDir.Z; //since our plane is along the z axis, we can assume that the A and B components of the plane are 0, and the C component is 1. and that the Distance of the plane is also 0, which simplifies our calculations. down to the near/dir. (see: http://www.yaldex.com/game-programming/0131020099_ch22lev1sec2.html
  Vector3 WorldPoint = WorldNear+WorldDir*D; //you can take the x/y position and treat these values the same way you did when the game was 2D.  You don't need the z value unless your game world has actual depth.

I have the code to do this using gluUnproject, but apparently, im too noob to help so, too bad...

I have the code to do this using gluUnproject, but apparently, im too noob to help so, too bad...

The functions to project/unproject exist (at least up to D3DX9), they're called D3DXVec3Project and D3DXVec3Unproject.

I do not know if this would help, I do not use this language, But when I did the same thing in the language I use, I had to relocate the call to the function to draw the mouse to a different section of the Draw/Renderworld Loop.

Where as I had the mouse draw prior to updating the world, I had to move it to after the update/render world code and then do a page flip.

This solved my problem as it was much like yours.

Again!! I stress that I am using a different language!!