Hi. I'm trying to make an FPS engine using DirectX 8 in VB6, and I'm having problems trying to move the camera appropriately. I guess this is due to my lack of understanding of matrices. I think I have managed to get the camera to move back and forth, and strafe correctly. Here's what I have: If DIState.Key(DIK_W) <> 0 Then z = z - 0.5 If DIState.Key(DIK_S) <> 0 Then z = z + 0.5 If DIState.Key(DIK_D) <> 0 Then x = x - 0.5 If DIState.Key(DIK_A) <> 0 Then x = x + 0.5 D3DXMatrixTranslation matView, x, y, z D3DDevice.SetTransform D3DTS_VIEW, matView Is this right? My main problem is trying to get the camera to look around. I have tried many different things, with none of them appearing to work. I'm finding it impossible. How am I supposed to do it? Any code would be more than helpful. :) (I have kinda started a topic on this before, but it was more to do with matrices than my actual problem. I thought by starting a more specific one, I could get more responses). Thanks, Luke

Quote:If DIState.Key(DIK_W) <> 0 Then z = z - 0.5
If DIState.Key(DIK_S) <> 0 Then z = z + 0.5
If DIState.Key(DIK_D) <> 0 Then x = x - 0.5
If DIState.Key(DIK_A) <> 0 Then x = x + 0.5

I see you've already counteracted what seemed like "mirrored" movement.

I'm assuming you already know about world matrices, and that you create a world matrix and set it to the device before you render an object. Well, the view matrix can be calculated just like a world matrix - with one exception: you invert the matrix after you calculate it.

So, some sample code might look like (I'm doing the best I can, I've never used VB):

Dim matPos As D3DXMATRIXDim matRot As D3DXMATRIXDim matView As D3DXMATRIXD3DXMatrixTranslation matView,x,y,z'xang, yang, and zang are in radiansD3DXMatrixRotationYawPitchRoll matRot,yang,xang,zangD3DXMatrixMultiply matView,matRot,matPosD3DXMatrixInverse matView,0,matViewD3DDevice.SetTransform D3DTS_VIEW,matView

You'll also want to change the signs in your movement code - you won't have to mirror the movement anymore.

When using that code, instead of the camera staying in one spot, looking around, the camera kind of rotates around the whole world. What am I doing wrong?
(I'm tearing my hair out over this. I've been stuck on it for far too long. Who would have thought that aiming a camera could be so damn difficult. D3DRM was soo much simpler.)

[Edited by - luke88 on August 11, 2005 1:31:23 PM]

Aha. By switching matView and matRot in your code, it now works! But with this, a new problem arises. Instead of the camera moving in the direction its facing, it would just run along its axis. For example, if I turn left by 90 degrees, and press W (to walk forward), the camera would strafe right. If I turn left by another 90 degrees, and press W, the camera would move backwards.

Ook, there's a typo in my last post that caused that problem. I'll change it all here.

Ooh boy, moving objects in the direction they're facing :) That's fun.



Hope that works out better.

YAY! It works perfectly. Thank you soo much! I can now finally sleep at night.
I really got learn how to use matrices. Meh.
Again, thank you :)

Sure! Linear algebra (vectors and matrices and stuff) is one of the hardest parts of learning how to do 3D graphics IMO, but after a while, it just becomes sort of a "oh, duh" kind of thing.