I wrote a terrain rendering engine that loads a height field and a texture. Now a Camera/Player can ... ,well should walk over this surface. I use the code below to calculate the movement of the Camera for every frame. The surface is displayed right but the camera moves totally wrong. Can anyone help me?

when LRangle is zero the Camera is looking in -z direction

long int delta ; // := time that passed since last frame in ms

const double DEGtoRAD=0.017453292; // PI/180

if(move forward)
{
double c=cos(PLAYER->LRangle * DEGtoRAD)
,s=sin(PLAYER->LRangle * DEGtoRAD);

PLAYER->movement.x=s * delta/1000;
PLAYER->movement.z=c * delta/1000;

PLAYER->position+ = PLAYER->movement;
}
if(move back)
{
double c=cos(PLAYER->LRangle * DEGtoRAD)
,s=sin(PLAYER->LRangle * DEGtoRAD);

PLAYER->movement.x=-s * delta/1000;
PLAYER->movement.z=-c * delta/1000;

PLAYER->position+ = PLAYER->movement;
}

Thanks Thanks Thanks Thanks !!
I nearly went mad, but it finally works. Nightshade you were right the code above is ok.I tested it again and again . Now I know that the error is somewhere else. I usually was calculating the height of the camera after it received a new position. So I set // in front of it and the walking routine worked fine . And finally I found the bug in the height calculation method , but there's still something wrong with it. The Camera is jumping up and down as if it walks over a ground with many holes and stairs.
I hope you can help me again.

void objekt::Camera()
{
glRotatef(HRangle,1,0,0);
glRotatef(LRangle,0,1,0);

glTranslatef(-position.x,-(position.y+1),-position.z);
// I am not sure about this anymore, here must be the second error
}

float objekt::hoehe(xyz &point)
{
int x,z; // next lower grid point
float deltax,deltaz; // distance along x and z axis to the next lower grid point
float ux,vz; // height difference between two grid points in x and z direction

x = (int)point.x;
deltax = point.x-x;

z = (int)point.z;
deltaz = point.z-z;

if(deltax+deltaz<1.0F) // example 1
{
ux = (surface[ z *width + x+1] - surface[z*width + x])*deltax;
vz = (surface[(z+1)*width + x ] - surface[z*width + x])*deltaz;
}
else // example 2 - I think here is something wrong
{
x++; // Position of P
z++;
deltax--; // new deltax and deltaz
deltaz--;
ux = (surface[ z *width + x-1] - surface[z*width + x])*deltax;
vz = (surface[(z-1)*width + x ] - surface[z*width + x])*deltaz;
}

punkt.y=surface[z*width + x] + ux + vz;

return point.y;
}

example 1
P-------o-------
|###|##/|######/ deltaz
|---*##/#|#####/#
|####/##|####/# *:=position of example 1
|###/###|###/## P:=next lower grid point of *
|##/####|##/### o:=grid point
|#/#####|#/####
|/######|/#####
o-------Z----
deltax

example 2 deltax+deltaz > 1
o-------o-------
|######/|######/
|#####/#|#####/ +:=position of example 2
|####/##|####/ P:=next grid point of +
|###/#+-|###/# o:=grid point
|##/##|#|##/##
|#/###|#|#/### deltaz
|/####|#|/####
o-------P----
deltax

# := empty space - ignore this

[This message has been edited by TheMummy (edited December 14, 1999).]

[This message has been edited by TheMummy (edited December 14, 1999).]

[This message has been edited by TheMummy (edited December 14, 1999).]