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zpr is currently a singleton class. An instance initializes OpenGL with a reasonable default projection and model view.

zpr works correctly when its state mirrors that of OpenGL. For example a call to glFrustrum or gluLookAt will change the viewing frustrum and zpr's values will not be the same as OpenGL's, hence zpr will break. Call zpr::update() to update zpr after a change.

Definition at line 73 of file zpr.h.


Public Member Functions
	zpr ()
	Look at the origin from (0.0,0.0,2.0) with up as (0.0,1.0,0.0) and the field of view 30 degrees.
void	readModelView ()
	Read the model view matrix from OpenGL.
void	readProjection ()
	Read the projection matrix from OpenGL and calculate left, right, bottom, top, zNear and zFar.
void	readScreenDimensions ()
	Read the current screen size from OpenGL.
void	update ()
	Read in the current OpenGL state.
void	write ()
	Write the current projection from zpr's parameters.
void	writeDefault ()
	Write a default projection from zpr.
void	writefromXaxis ()
	Draw having the x and y axes with equal scales, zpr::top needs to be re-calculated.
void	readMouse (GLdouble px, GLdouble py, GLdouble *pz, intc x, intc y) const
	Get the world mouse co-ordinates.
void	printInfo () const
	Print the frustrum values.
Static Public Member Functions
static void	motion (int x, int y)
	Glut motion call back function.
static void	mouse (int button, int state, int x, int y)
	Glut mouse call back function.
static void	reshape (int w, int h)
	Glut reshape call back function.
static double	vlen (GLdouble x, GLdouble y, GLdouble z)
	Distance function.
Public Attributes
GLdouble	left
	The minimum x screen coordinate.
GLdouble	right
	The maximum x screen coordinate.
GLdouble	bottom
	The minimum y screen coordinate.
GLdouble	top
	The maximum y screen coordinate.
GLdouble	zNear
	The closest z clipping plane.
GLdouble	zFar
	The farthest z clipping plane.
int	width
	Screen pixel width.
int	height
	Screen pixel height.
int	mouseX
	The mouse X position in pixeles.
int	mouseY
	The mouse Y position in pixeles.
bool	mouseLeft
	Was the left mouse button pressed?
bool	mouseMiddle
	Was the middle mouse button pressed?
bool	mouseRight
	Was the right mouse button pressed?
GLdouble	mouseXworld
	The mouse X position in world coordinates.
GLdouble	mouseYworld
	The mouse Y position in world coordinates.
GLdouble	mouseZworld
	The mouse Z position in world coordinates.
GLdouble	matrix [16]
	The model view matrix.
GLdouble	matrixI [16]
	The inverse of the model view matrix.
Static Public Attributes
static zpr *	global = 0
	zpr is a singleton with a global pointer.

Constructor & Destructor Documentation

zpr::zpr ( )

Look at the origin from (0.0,0.0,2.0) with up as (0.0,1.0,0.0) and the field of view 30 degrees.

Definition at line 322 of file zpr.cpp.

References glerrordisplay(), global, height, motion(), mouse(), mouseLeft, mouseMiddle, mouseRight, mouseXworld, mouseYworld, mouseZworld, readScreenDimensions(), reshape(), update(), width, zFar, and zNear.

00323 {
00324   global = this;
00325 
00326   mouseX = 0;
00327   mouseY = 0;
00328  
00329   mouseLeft   = false;
00330   mouseRight  = false;
00331   mouseMiddle = false;
00332 
00333   mouseXworld = 0.0;
00334   mouseYworld = 0.0;
00335   mouseZworld = 0.0;
00336  
00337   readScreenDimensions();
00338 
00339   glMatrixMode(GL_PROJECTION);
00340   glLoadIdentity();
00341 
00342   zNear=1.0;
00343   zFar=10.0;
00344   gluPerspective(30, (GLfloat) width/(GLfloat) height, zNear, zFar);
00345 
00346   glMatrixMode(GL_MODELVIEW);
00347   glLoadIdentity();
00348   gluLookAt
00349   (
00350     0.0, 0.0, 2.0,  // Eye
00351     0.0, 0.0, 0.0,  // Center
00352     0.0, 1.0, 0.0   // Up
00353   );
00354 
00355   glerrordisplay();
00356   update();
00357 
00358   glutReshapeFunc(reshape);
00359   glutMouseFunc(mouse);
00360   glutMotionFunc(motion);
00361 }

Member Function Documentation

void zpr::readModelView ( )

Read the model view matrix from OpenGL.

Definition at line 141 of file zpr.cpp.

References zprGLmatrix::invertMatrix(), matrix, and matrixI.

Referenced by update().

00142 {
00143   glGetDoublev(GL_MODELVIEW_MATRIX,matrix);
00144   zprGLmatrix::invertMatrix(matrixI,matrix);
00145 }

void zpr::readProjection ( )

Read the projection matrix from OpenGL and calculate left, right, bottom, top, zNear and zFar.

Definition at line 464 of file zpr.cpp.

References zprGLmatrix::access(), bottom, glerrordisplay(), left, right, top, zFar, and zNear.

Referenced by zprtest::test03(), and update().

00465 {
00466   static GLdouble pmatrix[16];
00467 
00468   glerrordisplay();
00469 
00470   glGetDoublev(GL_PROJECTION_MATRIX,pmatrix);
00471 
00472   glerrordisplay();
00473 
00474   zprGLmatrix mat(pmatrix);
00475 
00476   GLdouble a[6];
00477   a[0] = mat.access(0,0);
00478   a[1] = mat.access(1,1);
00479   a[2] = mat.access(0,2);
00480   a[3] = mat.access(1,2);
00481   a[4] = mat.access(2,2);
00482   a[5] = mat.access(2,3);
00483 
00484   // This is essentially an inverse of a glFrustrum(...) call.
00485   // Here the input parameters to the glFrustrum call are
00486   // calculated from the projection matrix.
00487   GLdouble c0 = (1.0-a[4])/(1.0+a[4]);
00488   //GLdouble z0 = a[5]*(c0+1.0)*-0.5/c0;
00489   GLdouble z0 = a[5]*(1.0+1.0/c0)*-0.50;
00490   GLdouble z1 = -c0*z0;
00491   GLdouble x0 = z0*(a[2]-1.0)/a[0];
00492   GLdouble x1 = (z0*2.0+a[0]*x0)/a[0];
00493   GLdouble y0 = z0*(a[3]-1.0)/a[1];
00494   GLdouble y1 = (z0*2.0+a[1]*y0)/a[1];
00495 
00496   left = x0;
00497   right = x1;
00498   bottom = y0;
00499   top = y1;
00500   zNear = z0;
00501   zFar = z1;
00502 
00503   glerrordisplay();
00504 }

void zpr::readScreenDimensions ( )

Read the current screen size from OpenGL.

Definition at line 453 of file zpr.cpp.

References glerrordisplay(), height, and width.

Referenced by update(), and zpr().

00454 {
00455   GLint viewport[4];
00456   glGetIntegerv( GL_VIEWPORT, viewport );
00457 
00458   glerrordisplay();
00459 
00460   width = viewport[2];
00461   height = viewport[3];
00462 }

void zpr::update ( ) [inline]

Read in the current OpenGL state.

Definition at line 116 of file zpr.h.

References readModelView(), readProjection(), and readScreenDimensions().

Referenced by test01obj< P, PD >::eval(), cubegui::prog01(), gobjtest::test001(), graphmisctest::test002(), triangletest::test01(), tetrahedrontest::test01(), plotpolartest::test01(), planeinttest::test01(), diskinttest::test01(), d2simplextest::test01(), circleD2test::test01(), boxOBBhalfspaceD2test::test01(), menusystemtest::test01(), test01(), vrmltest::test02(), triangletest::test02(), tetrahedrontest::test02(), diskinttest::test02(), menusystemtest::test02(), regionD2linkedtest::test02(), meshpatchtest::test02(), helixtest::test03(), triangletest::test03(), diskinttest::test03(), treeindexedtest::test03(), meshpatchtest::test03(), meshpatchtest::test04(), triangles3Tdisplaytest::test05(), treeindexedtest::test05(), partitionstest::test06(), and zpr().

00117   {
00118     readScreenDimensions();
00119     readModelView();
00120     readProjection();
00121   }

void zpr::write ( )

Write the current projection from zpr's parameters.

Definition at line 153 of file zpr.cpp.

References bottom, glerrordisplay(), height, left, right, top, width, zFar, and zNear.

Referenced by writeDefault(), and writefromXaxis().

00154 {
00155   glViewport(0,0,width,height);
00156 
00157   glMatrixMode(GL_PROJECTION);
00158   glLoadIdentity();
00159   assert(zNear>0.0);
00160   assert(zFar>zNear);
00161   glFrustum(left,right,bottom,top,zNear,zFar);
00162   glMatrixMode(GL_MODELVIEW);
00163 
00164   glerrordisplay();
00165 }

void zpr::writeDefault ( )

Write a default projection from zpr.

Definition at line 177 of file zpr.cpp.

References bottom, height, left, right, top, width, write(), zFar, and zNear.

00178 {
00179   assert( height>0.0);
00180   assert( width>0.0);
00181 
00182   left=-1.0;
00183   right=1.0;
00184 
00185   double dy = 2.0 * (double) height / (double)width;
00186   bottom=-dy*0.5;
00187   top=dy*0.5;
00188 
00189   zNear=1.0;
00190   zFar=6.0;
00191   write();
00192 }

void zpr::writefromXaxis ( )

Draw having the x and y axes with equal scales, zpr::top needs to be re-calculated.

This function is useful in plotting maths graphs.

Definition at line 375 of file zpr.cpp.

References bottom, height, left, right, top, width, and write().

00376 {
00377   GLdouble const xlen = right - left;
00378   GLdouble const ylen = xlen * (GLdouble) height / (GLdouble) width;
00379   top = bottom + ylen;
00380 
00381   write();
00382 }

void zpr::motion	(	int	x,
		int	y
	)			`[static]`

Glut motion call back function.

Definition at line 250 of file zpr.cpp.

References global, and motionzpr().

Referenced by zpr().

00251 {
00252   assert(global!=0);
00253   global->motionzpr(x,y);
00254 }

void zpr::mouse	(	int	button,
		int	state,
		int	x,
		int	y
	)			`[static]`

Glut mouse call back function.

Definition at line 194 of file zpr.cpp.

References global, and mousezpr().

Referenced by zpr().

00195 {
00196   assert(global!=0);
00197 
00198   global->mousezpr(button,state,x,y);
00199 }

void zpr::reshape	(	int	w,
		int	h
	)			`[static]`

Glut reshape call back function.

Definition at line 147 of file zpr.cpp.

References global, and reshapezpr().

Referenced by zpr().

00148 {
00149   assert(zpr::global!=0);
00150   global->reshapezpr(_width,_height);
00151 }

void zpr::readMouse	(	GLdouble *	px,
		GLdouble *	py,
		GLdouble *	pz,
		intc	x,
		intc	y
	)			const

Get the world mouse co-ordinates.

Definition at line 202 of file zpr.cpp.

References bottom, left, right, top, and zNear.

00209 {
00210 //    Use the ortho projection and viewport information
00211 //    to map from mouse co-ordinates back into world 
00212 //    co-ordinates
00213 
00214   int viewport[4];
00215   glGetIntegerv(GL_VIEWPORT,viewport);
00216 
00217   *px = (GLdouble)(x-viewport[0])/(GLdouble)(viewport[2]);
00218   *py = (GLdouble)(y-viewport[1])/(GLdouble)(viewport[3]);
00219 
00220   *px = left + (*px)*(right-left);
00221   *py = top  + (*py)*(bottom-top);
00222   *pz = zNear;
00223 }

static double zpr::vlen	(	GLdouble	x,
		GLdouble	y,
		GLdouble	z
	)			`[inline, static]`

Distance function.

Definition at line 173 of file zpr.h.

00174     { return sqrt(x*x+y*y+z*z); }

void zpr::printInfo ( ) const

Print the frustrum values.

Definition at line 363 of file zpr.cpp.

References bottom, height, left, right, SHOW, top, width, zFar, and zNear.

Referenced by zprtest::test01(), and zprtest::test03().

00364 {
00365 cout << SHOW(left) << endl;
00366 cout << SHOW(right) << endl;
00367 cout << SHOW(bottom) << endl;
00368 cout << SHOW(top) << endl;
00369 cout << SHOW(zNear) << endl;
00370 cout << SHOW(zFar) << endl;
00371 cout << SHOW(width) << endl;
00372 cout << SHOW(height) << endl;
00373 }