D3d Camera position type question

ThaUnknownProgga · 2000-07-15T07:28:05

I have my engine currently utilizing the view world and perspective matrices after a long time of static renderings. The matrix code i''m using is basically the same as on this page: http://www.ziron.com/links/directx/drawprim.htm This implemention is alright except I can''t seem to get the location of the camera. This is because it''s just a view matrix, not an actual camera implementation, but i''ve had a lot of trouble implementing a camera system. i was wondering how then to get the current position of the view matrix, or help on creating a good camera system. thanks in advance

Graphics and GPU Programming Programming

Started by ThaUnknownProgga July 12, 2000 02:19 AM

14 comments, last by ThaUnknownProgga 23 years, 9 months ago

daedalusd

122

July 13, 2000 05:34 PM

Witchlord helped me out with this a while back, but anyway here is a rough example of how it works with mine.

        vEyePt = MakeVector(vx, vy, vz);vLookatPt = MakeVector(vx + (float)cos(XAxisRotate * g_DEGTORAD) * (float)sin(YAxisRotate * g_DEGTORAD), vy + (float)sin(XAxisRotate * g_DEGTORAD), vz + (float)cos(XAxisRotate * g_DEGTORAD) * (float)cos(YAxisRotate * g_DEGTORAD));vUpVec = MakeVector(0,1,0);D3DUtil_SetViewMatrix( matView, Camera->vEyePt, Camera->vLookatPt, Camera->vUpVec);g_pd3dDevice->SetTransform(D3DTRANSFORMSTATE_VIEW, &matView);//I just keep track of my camers X/Y/Z position, and it's //rotation around the X and Y axis (this is a simple //implementation of an fps camera movement).//Then to move forwards/backwards etc just do something like   vx +=(float)cos(XAxisRotate * g_DEGTORAD) * (float)sin(YAxisRotate * g_DEGTORAD) * distance;   vy +=(float)sin(XAxisRotate * g_DEGTORAD) * distance;   vz +=(float)cos(XAxisRotate * g_DEGTORAD) * (float)cos(YAxisRotate * g_DEGTORAD) * distance;

This will move in the direction the camera is facing. Just drop the line which updates the VY coord if you want to ignore movement up or down.

(This is some old code I had lying around, and is by no means guarenteed working anymore =)

HTH

Adam "Nutz" Hoult
VB Gaming Central

Edited by - daedalusd on July 13, 2000 6:36:24 PM

ThaUnknownProgga

122

Author

July 13, 2000 06:13 PM

Thanks, but i''d still like to know how to calculate the World Matrix with a position and a matrix describing orientation

WitchLord

4,834

July 14, 2000 12:05 AM

Just multiply the orientation matrix with the translation matrix, and you have the world matrix

To build the view matrix you multiply the inverted translation matrix with the transposed orientation matrix

- WitchLord

AngelCode.com - game development and more - Reference DB - game developer references
AngelScript - free scripting library - BMFont - free bitmap font generator - Tower - free puzzle game

ThaUnknownProgga

122

Author

July 14, 2000 09:55 PM

Well, i scrapped my old code and followed your tutorial witchlord, and it worked great. i was wondering thought, using this type of camera setup, how would I set my camera to have a lookat position which it looks at?

mitchw

162

July 15, 2000 01:15 AM

Look at the d3d framework source code, I believe it has a look at function, with source. Look in the d3dutil files.

WitchLord

4,834

July 15, 2000 07:28 AM

If you want to use a look at position with the way I''m doing the camera, you will have to rotate the camera your self. Find the yaw angle that the camera needs to be in to look in the direction of the look at vector. Then find the pitch angle so that the camera is looking at the right height as well. Then use these two angles when setting up the view matrix.

- WitchLord

AngelCode.com - game development and more - Reference DB - game developer references
AngelScript - free scripting library - BMFont - free bitmap font generator - Tower - free puzzle game

D3d Camera position type question

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