GX Camera Issues

[mv2112]

Im trying to make a FPS type view in GX and iv got it working except for 1 small problem. Im trying to rotate the camera:

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   angle2+=d;//New Viewing angle
	float y=cam[0].y+sin(DegToRad(angle2)); //Get New Y From the New View Angle and add it to the cameras position
	cam[2].y=y; //set the View Y to the generated Y ^^ //guVector cam[3]
	guMtxIdentity(m);
	guLookAt(m, &cam[0], &cam[1], &cam[2]); //reload camera

Basicly it just takes an angle, calculates a y chord for the view vector and loads it into the view matrix (m). This works perfectly except for when you go all the way up or down. I think this is because im not updating the Up vector. Would i just inverse the slope of the line between the view point and camera location and add/subtract it to the up vector? Much help would be appreciated. And also, i have one last question: I've tried to use translations and rotations on the view matrix but they seem to have no effect. Are you not able to use the regular transformation functions on view matrices?

Thanks
mv2112

[ccfreak2k]

I actually have this kind of view implemented to some extent in the lesson 10 code of the "neheGX" examples. Specifically, this section will be relevant:

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f32 lookupdown; // Vertical angle, 0 is straight ahead
if (lookupdown > 90)  lookupdown = 90.0F;
if (lookupdown < -90) lookupdown = -90.0F;

Kind of simple, but it works. If you instead want the camera to flip around when the user goes past these two "ends", you can simply add/subtract 180 on each of the angles to get the camera to quickly spin around, but the user might find this disorienting.

EDIT: Someone on IRC suggests:

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cam[2].x = cam[0].x + cos(yaw)cos(pitch);
cam[2].y = cam[0].y + sin(pitch);
cam[2].z = cam[0].z + sin(yaw)cos(pitch);

Said someone also adds: "...pitch also modifies x and z, not just y."

Use whichever works best for you.

[mv2112]

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f32 lookupdown; // Vertical angle, 0 is straight ahead
if (lookupdown > 90)  lookupdown = 90.0F;
if (lookupdown < -90) lookupdown = -90.0F;

Works Perfectly! Thanks!