[gav]

Hi,

I'm currently writing a program which requires the coordinates of the mouse to place things within DirectX. The code I'm using is as follows:

Function GetWorldMouseClickPoint() As D3DVECTOR
'return position in the world where the mouse was clicked
g_D3DDevice.GetViewport viewport
vIn.x = CursorX: vIn.y = CursorY: vIn.Z = 0
D3DXVec3Unproject vNear, vIn, viewport, matProj, matView, matWorld
'compute point on far clip plane at cursor
vIn.Z = 1
D3DXVec3Unproject vFar, vIn, viewport, matProj, matView, matWorld
D3DXVec3Subtract vDir, vFar, vNear

t = (-(vFar.Z) / vDir.Z)
GetWorldMouseClickPoint.x = vFar.x + t * vDir.x
GetWorldMouseClickPoint.y = vFar.y + t * vDir.y
end function

and i get the X,Y coordinates of the mouse from ...

Private Sub Form_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
CursorX = x / Screen.TwipsPerPixelX
CursorY = y / Screen.TwipsPerPixelY
End Sub

The problem I'm having is that the coordinates returned from GetWorldMouseClickPoint don't quite match the movement of the mouse. For example if I move the mouse upwards only, the image which I'm placing at the coordinates of GetWorldMouseClickPoint will appear to move diagonally up and to the left, but its x coordinate will remain the same.

I'm guessing this is something to do with my view or world matrices, but I don't fully understand how they work and so am having trouble finding a solution to my problem. The matrices are set up as follows

sub SetUpView()
D3DXMatrixRotationY matWorld, 0
g_D3DDevice.SetTransform D3DTS_WORLD, matWorld
D3DXMatrixLookAtLH matView, vec3(0#, 0#, camZ), _
vec3(camX, camY, 0), _
vec3(0, 1#, 0#)
g_D3DDevice.SetTransform D3DTS_VIEW, matView
D3DXMatrixPerspectiveFovLH matProj, 3.14159265358979 / 3, 1, 1, 2000
g_D3DDevice.SetTransform D3DTS_PROJECTION, matProj
end sub

the variables CamX and CamY are both = 50 and CamZ = -900.

I should also mention that I'm trying to show everything in 2 Dimensions, however when i move anything, I'm giving it a Z coordinate to match its Y coordinate, so that as something moves up the screen, it also appears to move away. I initially thought that was a possible cause of my problem, but couldn't see a reason why.

I would greatly appreciate any ideas?

Thanks in advance,

Gav.

[Banjo]

Are you in full screen or windowed mode?

[gav]

I'm in full screen mode

[gav]

Ah, after reading through my question again I've just found out the answer. The z coordinate is the only possible place I could be going wrong. If I set the z coordinate to always be 0 then I always get teh correct position.

I guess it really does help to just talk out your problems !!

Thanks for the help!

gav.