View Full Version : Viewing transformations in 3D

05-26-2000, 03:39 AM
I am trying to make a simple flight simulator. I am not being able to set up the viewing sytem for this. Can anybody help in this regard. I want all motions of a flying object. I want to do this via the keyboard. Please keep in mind that i have just started OpenGL.

Glenn Upton
05-26-2000, 09:39 PM
Sure .. here is what I stole...from super bible i think...
//************************************************** ************************
// Update the position of the camera.This function can vary wildly depending
// on how motion is acheived. For a flight sim, motion will always be along the
// viewer's Z axis. For a first person walking around, motion will always be in
// the XY plane. Even if the camera tilts down (to look at the ground), or up
// (to look at the sky), the player still only moves along the XY plane.
// This function must be called continuously, or the timed motion will not work.
// If this function is called only when a key press is made, then the time between
// calls will be huge and the camera will 'rocket' to the new location with each key
// press
void UpdatePosition(struct CAMERA *pCamera)
float fLinearVelocity = 0.0f;
float fAngularVelocityY = 0.0f;
float fAngularVelocityX = 0.0f;
float fAngularVelocityZ = 0.0f;
float fTime, fXDelta,fAngle, fZDelta;
double fSeconds;
float elevation = 0.0f;

LARGE_INTEGER currentTime;

// Keyboard Input
// Check for forward or backwards Motion
fLinearVelocity = 6.0f;

fLinearVelocity = -6.0f;
// check for elevation
elevation = 0.25f;

elevation = -0.25f;

// Check for spin left/right (Y Axis rotation)
fAngularVelocityY = -45.0f;

fAngularVelocityY = 45.0f;

// Check for looking up and down
if(GetAsyncKeyState(0x41)) // A key
fAngularVelocityX = -9.50f;

if(GetAsyncKeyState(0x5a)) // Z key
fAngularVelocityX = 9.50f;

// Adjust position and orientation. Get the time since the last
// check. If the velocity = 0 (no keypress or mouse movement)
// then the motion will be nil...
// D = vt
fTime = (float)(currentTime.QuadPart - lastTime.QuadPart)/
lastTime = currentTime;

fSeconds = (double)(currentTime.QuadPart - globeTime.QuadPart)/

// calc wheel rotation
wheel_angle = (float(fSeconds * 18.0f));
wheel_rotation = fmod(wheel_angle, 360.0f);

// Update Rotation angles (clamp the X rotation)
fAngle = fTime * fAngularVelocityX;
fAngle += pCamera->orientation[0];

if((fAngle < 90.0f) && (fAngle > -90.0f))
pCamera->orientation[0] = fAngle;

pCamera->orientation[1] += fTime * fAngularVelocityY;

// Update linear position
fTime = fTime * fLinearVelocity;
fXDelta = fTime * (float)(sin(DEGTORAD(pCamera->orientation[1])));
fXDelta += pCamera->position[0];
fZDelta = fTime * (float)(cos(DEGTORAD(pCamera->orientation[1])));
fZDelta += pCamera->position[2];

pCamera->position[1] += elevation;

pCamera->position[0] = fXDelta;
pCamera->position[2] = fZDelta;

// Halt the camera at the boundaries of the Virtual World.

if(pCamera->position[0] > 150.0f)
pCamera->position[0] = 150.0f;

if(pCamera->position[0] < -150.0f)
pCamera->position[0] = -150.0f;

if(pCamera->position[2] > 150.0f)
pCamera->position[2] = 150.0f;

if(pCamera->position[2] < -150.0f)
pCamera->position[2] = -150.0f;