what is the initial value of c_fFactor?
2
I tried with the spheric coordinates some time ago and I didn’t solve anything (but I don’t remember if I was making the change in the up vector). I would have to take a look at the quaternions… A friend recommended me this webpage about it:
http://en.wikipedia.org/wiki/Qua
Nice story the one about Hamilton and the bridge…
You rotate first on the X and then on the Y Axis and not visa versa:
//rotate automatically the sphere on it’s Y axis
glTranslatef(0.0f,10.0f,40.0f);
glRotatef( rotateSphere , 0.0f, 1.0f , 0.0f);
glRotatef ((GLfloat)90.0, (GLfloat)1.0, (GLfloat)0.0, (GLfloat)0.0);
glScalef(5.0f, 5.0f, 5.0f);
gluSphere(q, 1.0f, 32, 16); // Draw Sphere
never mind my last statement. It looks as your order of rotations is correct.
Maybe this will give you some ideas on rotating a sphere(without texture):/******************************************************
*
*
-
OPEN GL
-
GLOBE TROT VER 0.00001
********************************************************/
/I N C L U D E S/
#include <windows.h>
#include <GL/gl.h>
#include <GL/glu.h>
/Defines/
#define BLACK_INDEX 0 /black for background/
#define GREEN_INDEX 14 /green for wireframe globe object/
#define WIDTH 640 /starting window pixel width/
#define HEIGHT 480 /starting window pixel height/
#define GLOBE 1 /The object to be rendered/
/*Prototypes */
LONG WINAPI MainWndProc (HWND, UINT, WPARAM, LPARAM);
BOOL bSetupPixelFormat(HDC);
GLvoid resize(GLsizei, GLsizei);
GLvoid initializeGL(GLsizei, GLsizei);
GLvoid drawScene(GLvoid);
void polarView( GLdouble, GLdouble, GLdouble, GLdouble);
/OpenGL globals/
GLfloat latitude, longitude, latinc, longinc;
GLdouble radius;
CHAR szAppName[]=“Win OpenGL”;
HWND ghWnd; /* handle for our window /
HDC ghDC; / handle for device context /
HGLRC ghRC; / handle for render context */
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
MSG msg;
WNDCLASS wndclass;
/* Register the frame class */
wndclass.style = 0;
wndclass.lpfnWndProc = (WNDPROC)MainWndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon (hInstance, szAppName);
wndclass.hCursor = LoadCursor (NULL,IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wndclass.lpszMenuName = szAppName;
wndclass.lpszClassName = szAppName;
if (!RegisterClass (&wndclass) )
return FALSE;
/* Create the frame */
ghWnd = CreateWindow (szAppName,
"Rotating OpenGL Globe",
WS_OVERLAPPEDWINDOW | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
CW_USEDEFAULT,
CW_USEDEFAULT,
WIDTH,
HEIGHT,
NULL,
NULL,
hInstance,
NULL);
/* make sure window was created */
if (!ghWnd)
return FALSE;
/* show and update main window */
ShowWindow (ghWnd, nCmdShow);
UpdateWindow (ghWnd);
/* animation loop */
while (1)
{
while (PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE) == TRUE)
{
if (GetMessage(&msg, NULL, 0, 0) )
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else
{
return TRUE;
}
}
drawScene(); // Call drawScene function
}
} // Close WinMain
/* main window procedure */
LONG WINAPI MainWndProc (
HWND hWnd, /*handle for our window */
UINT uMsg, /messages/
WPARAM wParam,
LPARAM lParam)
{
LONG lRet = 1;
PAINTSTRUCT ps;
RECT rect;
switch (uMsg) {
/get device context with window´s handle/
case WM_CREATE:
ghDC = GetDC(hWnd);
if (!bSetupPixelFormat(ghDC))
PostQuitMessage (0);
/get render context concurrent with device context/
ghRC = wglCreateContext(ghDC);
wglMakeCurrent(ghDC, ghRC);
GetClientRect(hWnd, &rect);
initializeGL(rect.right, rect.bottom);
break;
/Win32 Api Paint/
case WM_PAINT:
BeginPaint(hWnd, &ps);
EndPaint(hWnd, &ps);
break;
/Win32 Api window´s size/
case WM_SIZE:
GetClientRect(hWnd, &rect);
resize(rect.right, rect.bottom);
break;
/close window and reset render and device context to zero/
case WM_CLOSE:
if (ghRC)
wglDeleteContext(ghRC);
if (ghDC)
ReleaseDC(hWnd, ghDC);
ghRC = 0;
ghDC = 0;
DestroyWindow (hWnd);
break;
/* destroy window and delete render and device context*/
case WM_DESTROY:
if (ghRC)
wglDeleteContext(ghRC);
if (ghDC)
ReleaseDC(hWnd, ghDC);
PostQuitMessage (0);
break;
/User controlled Kyboard routines/
case WM_KEYDOWN:
switch (wParam) {
case VK_LEFT:
longinc += 0.2F;
break;
case VK_RIGHT:
longinc -= 0.2F;
break;
case VK_UP:
latinc += 0.2F;
break;
case VK_DOWN:
latinc -= 0.2F;
break;
}
/* Windows procedure for messages*/
default:
lRet = DefWindowProc (hWnd, uMsg, wParam, lParam);
break;
}
return lRet;
}
BOOL bSetupPixelFormat(HDC hdc)
{
PIXELFORMATDESCRIPTOR pfd, *ppfd;
int pixelformat;
ppfd = &pfd;
ppfd->nSize = sizeof(PIXELFORMATDESCRIPTOR);
ppfd->nVersion = 1;
ppfd->dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER;
ppfd->dwLayerMask = PFD_MAIN_PLANE;
ppfd->iPixelType = PFD_TYPE_COLORINDEX;
ppfd->cColorBits = 8;
ppfd->cDepthBits = 16;
ppfd->cAccumBits = 0;
ppfd->cStencilBits = 0;
pixelformat = ChoosePixelFormat(hdc, ppfd);
if ( (pixelformat = ChoosePixelFormat(hdc, ppfd)) == 0 )
{
MessageBox(NULL, "ChoosePixelFormat failed", "Error", MB_OK);
return FALSE;
}
if (SetPixelFormat(hdc, pixelformat, ppfd) == FALSE)
{
MessageBox(NULL, "SetPixelFormat failed", "Error", MB_OK);
return FALSE;
}
return TRUE;
}
GLvoid resize( GLsizei width, GLsizei height )
{
GLfloat aspect;
glViewport( 0, 0, width, height );
aspect = (GLfloat) width / height;
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
gluPerspective( 45.0, aspect, 3.0, 7.0 );
glMatrixMode( GL_MODELVIEW );
}
/* Object Set Up */
GLvoid createObjects()
{
GLUquadricObj *quadObj;
glNewList(GLOBE, GL_COMPILE);
quadObj = gluNewQuadric ();
gluQuadricDrawStyle (quadObj, GLU_LINE);
gluSphere (quadObj, 1.5, 16, 16);
glEndList();
}
/* Function Initialize Scene objects */
GLvoid initializeGL(GLsizei width, GLsizei height)
{
GLfloat maxObjectSize, aspect;
GLdouble near_plane, far_plane;
/* Initial depth and background */
glClearIndex( (GLfloat)BLACK_INDEX);
glClearDepth( 1.0 );
/* Initial depth test */
glEnable(GL_DEPTH_TEST);
glMatrixMode( GL_PROJECTION );
aspect = (GLfloat) width / height;
gluPerspective( 45.0, aspect, 3.0, 7.0 );
glMatrixMode( GL_MODELVIEW );
near_plane = 3.0;
far_plane = 7.0;
maxObjectSize = 3.0F;
radius = near_plane + maxObjectSize/2.0;
latitude = 0.0F;
longitude = 0.0F;
latinc = 3.0F;
longinc = 0.0F;
createObjects();
}
void polarView(GLdouble radius, GLdouble twist, GLdouble latitude,
GLdouble longitude)
{
glTranslated(0.0, 0.0, -radius);
glRotated(-twist, 0.0, 0.0, 1.0);
glRotated(-latitude, 1.0, 0.0, 0.0);
glRotated(longitude, 0.0, 0.0, 1.0);
}
GLvoid drawScene(GLvoid)
{
/Clear previous frame depth and color buffer enabling next frame/
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
/matrix stack save transformations/
glPushMatrix();
/*User´s Kayboard values*/
latitude += latinc*.3;
longitude += longinc*.3;
/*Call to object´s function with current values*/
polarView( radius, 0, latitude, longitude );
/* Final Call for Objects to be rendered*/
glIndexi(GREEN_INDEX);
glCallList(GLOBE);
/*restore OpenGl´s matrix stack transformations */
glPopMatrix();
/* Make scene visible */
SwapBuffers(ghDC);
}