[solved]First Person LookAt Coords /w some code

OpenGL Development JOGL Development
#1

I hate feeling needy and posting on this board like three times a week but I guess it’s a good thing this board exists other-wise my programming problems wouldn’t get solved :D.


public Point3D translateByAngle(float oX, float oY, float oZ,
			float length,
			float angleX,float angleY,float angleZ){
		float rad, xOld, yOld, zOld;
		float x = length, y = 0,z = 0;
		//X ANGLE
		rad = angleX * (float)(Math.PI / 180);		
		xOld = x;zOld = z;
		z = (float)((zOld * Math.cos(rad)) - (xOld * Math.sin(rad)));
		x = (float)((zOld * Math.sin(rad)) + (xOld * Math.cos(rad)));	
		//Y ANGLE
		rad = angleY * (float)(Math.PI / 180);		
		yOld = y; zOld = z;
		y = (float)((yOld * Math.cos(rad))- (zOld * Math.sin(rad)));
		z = (float)((yOld * Math.sin(rad)) + (zOld * Math.cos(rad)));	
		//Z ANGLE
		rad = angleZ * (float)(Math.PI / 180);
		yOld = y; xOld = x;
		x = (float)((xOld * Math.cos(rad)) - (yOld * Math.sin(rad)));
		y = (float)((xOld * Math.sin(rad)) + (yOld * Math.cos(rad)));	
		return new Point3D(oX + x, oY + y, oZ + z);
	}

I’m using this code to calculate the point in 3-Space for my camera to look at. It pretty much takes the angle of the camera and the location of the camera and the distance of sight and calculates a new point(LookAt point).

Though there’s some minor problems with it for what I am trying to do. such as if I rotate the Y-Axis the angle in which I am looking up at then changes. When I want it to stay at the same “pitch”.

Is there a Z-Rotation for the camera? Is this not the series of equations I should be using? Is there a better way to do this?

My main problem is having my shooting script work with my camera. So I use that same method to shoot as well.

Thanks for reading, if you don’t understand the problem I can post, you-tube video, a diagram a better explanation, and/or code. Just lemme know :smiley:

#2

To be more specific…

I know you guys have done first person perspective… How’d you all do it?

#3

Don’t apply a delta-rotation on the coordinates from the last frame. Instead store the overall rotation angles in member variables. Everything else depends on the order of the rotations.

#4

On GameDev.net BobJahnova helped me out.

tempX = -(float)(Math.cos(Xangle) * Math.sin(Yangle));
tempZ = (float)(Math.cos(Xangle) * Math.cos(Yangle));
tempY = (float) Math.sin(Xangle);

is the proper vector thing haha Thanks though cylab!

#5

Maybe just use a vector math library :wink: vecmath, openmali, joglutils…

#6

Didn’t even know such things existed haha. I’ll have to look into those!

#7

hum… better that you do it yourself once, after use any libraries but for the first time do it yourself, this is really a simple problem what you need is only three method to rotate around X,Y,Z then use them in the correct order. usually for fps (if Y is up an Z going front of you) you just have to rotate around X then around Y.usually for FPS you wont rotate around Z but if you wich to do some kind of roll just rotate around Z at first.