[HELP] Processing camera data

[skra]

Hi,
i came across this thread a while ago, but i can't get this thing working. I've updated the offsets and from what i can tell it's reading the right values. Nevertheless i get totally absurd values as result. Therefor i've got 2 questions:

1. What does the matrix (fViewMat) contain/represent?
2. What is this math operation called, and why is fViewMat with the new values never used (assigning new values = pointless?) ?

	float fInv[3][3];
	fInv[0][0] = camera.fViewMat[1][1]*camera.fViewMat[2][2]-camera.fViewMat[1][2]*camera.fViewMat[2][1];
	fInv[1][0] = camera.fViewMat[1][2]*camera.fViewMat[2][0]-camera.fViewMat[1][0]*camera.fViewMat[2][2];
	fInv[2][0] = camera.fViewMat[1][0]*camera.fViewMat[2][1]-camera.fViewMat[1][1]*camera.fViewMat[2][0];
	float fDet = camera.fViewMat[0][0]*fInv[0][0]+camera.fViewMat[0][1]*fInv[1][0]+camera.fViewMat[0][2]*fInv[2][0];
	float fInvDet = 1.0f / fDet;
	fInv[0][1] = camera.fViewMat[0][2]*camera.fViewMat[2][1]-camera.fViewMat[0][1]*camera.fViewMat[2][2];
	fInv[0][2] = camera.fViewMat[0][1]*camera.fViewMat[1][2]-camera.fViewMat[0][2]*camera.fViewMat[1][1];
	fInv[1][1] = camera.fViewMat[0][0]*camera.fViewMat[2][2]-camera.fViewMat[0][2]*camera.fViewMat[2][0];
	fInv[1][2] = camera.fViewMat[0][2]*camera.fViewMat[1][0]-camera.fViewMat[0][0]*camera.fViewMat[1][2];
	fInv[2][1] = camera.fViewMat[0][1]*camera.fViewMat[2][0]-camera.fViewMat[0][0]*camera.fViewMat[2][1];
	fInv[2][2] = camera.fViewMat[0][0]*camera.fViewMat[1][1]-camera.fViewMat[0][1]*camera.fViewMat[1][0];
	camera.fViewMat[0][0] = fInv[0][0]*fInvDet;
	camera.fViewMat[0][1] = fInv[0][1]*fInvDet;
	camera.fViewMat[0][2] = fInv[0][2]*fInvDet;
	camera.fViewMat[1][0] = fInv[1][0]*fInvDet;
	camera.fViewMat[1][1] = fInv[1][1]*fInvDet;
	camera.fViewMat[1][2] = fInv[1][2]*fInvDet;
	camera.fViewMat[2][0] = fInv[2][0]*fInvDet;
	camera.fViewMat[2][1] = fInv[2][1]*fInvDet;
	camera.fViewMat[2][2] = fInv[2][2]*fInvDet;
	float fView[3];
	fView[0] = fInv[0][0]*fDiff[0]+fInv[1][0]*fDiff[1]+fInv[2][0]*fDiff[2];
	fView[1] = fInv[0][1]*fDiff[0]+fInv[1][1]*fDiff[1]+fInv[2][1]*fDiff[2];
	fView[2] = fInv[0][2]*fDiff[0]+fInv[1][2]*fDiff[1]+fInv[2][2]*fDiff[2];

Thanks for your help!

[dekz]

Without looking at any other code, I can only asume fViewMat is the View Matrix, which you need to set every time your camera changes position.

There are also 3 matrices needed, world, view and projection. (SO it can properly transfrom geometry)

Correct me if I'm wrong because its quite probable.

[skra]

well i have the camera position, the object position, a field of view float and the view matrix. that's 1 matrix, 1 float, and 2 "vectors" but not "3 matrices " =/ perhapse some of the other matrices can be created out of that data but i don't know how

[dekz]

I am not experienced in camera projections so be wary, but hopefully this may help you a little.

I think (without an in depth look) that the math you are talking about is the mapping of a 3d point in the world to a 2d plane. You may find more info with a Camera matrix search

[Robske]

I think this was mentioned in one of those 3D->2D threads
3D projection - Wikipedia, the free encyclopedia

[skra]

ok thanks everyone! that pointed me in the right direction. i'm getting better values now. however they are still not correct and so i'm not sure i'm reading the matrix out of memory correct. The numbers represent the offsets from the beginning of the matrix block i'm reading:

0 | 12 | 24 
4 | 16 | 28
8 | 20 | 32

or should i read it like this?

0 | 4 | 8
12 | 16 | 20
24 | 28 | 32

[YetiHunter]

thanks that solved my problem as well
btw: you have to read the matrix the second way

[skra]

thanks alot!