infinitecmdz

11-22-2005, 06:27 PM

hey guys,

I have a problem in picking. I read the tutorials at lighthouse website and i did exactly what they had taught. Well heres my code :

My renderScene code :

GLvoid RenderScene()

{

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) ;

glLoadIdentity() ;

gluLookAt(CameraObj.mPosition.x , CameraObj.mPosition.y , CameraObj.mPosition.z ,

CameraObj.mView.x , CameraObj.mView.y , CameraObj.mView.z ,

CameraObj.mUp.x , CameraObj.mUp.y , CameraObj.mUp.z) ;

//Draw the x , y , z Axis and the grid initially.

DrawAxis() ;

Draw3DGrid() ;

DrawGrid(GL_RENDER) ;

glScalef(0.030f , 0.030f , 0.030f) ;

glRotatef(180.0 , 0.0f , 1.0f , 0.0f) ;

DrawObject() ;

glFlush() ;

glutSwapBuffers() ;

}Heres my DrawGrid code. This is made of points which I must pick...

GLvoid DrawGrid(int mode)

{

if(mode == GL_SELECT)

{

glInitNames();

//glPushName(0);

}

int i , j ;

glDisable(GL_LIGHTING) ;

glPointSize(6.0f) ;

//Draw the line segments

glColor3f(1.0f , 1.0f , 0.0f) ;

for(i = 0 ; i < 8 ; i++)

{

for(j = 0 ; j < 8 ; j++)

{

glBegin(GL_LINE_STRIP) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glVertex3f(ControlPoints[i + 1][j][0] , ControlPoints[i + 1][j][1] , ControlPoints[i + 1][j][2]) ;

glVertex3f(ControlPoints[i + 1][j + 1][0] , ControlPoints[i + 1][j + 1][1] , ControlPoints[i + 1][j + 1][2]) ;

glVertex3f(ControlPoints[i][j + 1][0] , ControlPoints[i][j + 1][1] , ControlPoints[i][j + 1][2]) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glEnd() ;

}

}

//Draw the control vertices.

glColor3f(0.0f , 1.0f , 0.0f) ;

int k = 1 ;

for(i = 0 ; i < 10 ; i++)

{

if(mode == GL_SELECT)

glPushName(i) ;

for(j = 0 ; j < 10 ; j++)

{

if(mode == GL_SELECT)

glPushName(j);

glBegin(GL_POINTS) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glEnd() ;

glPopName() ;

}

glPopName() ;

}

glLineWidth(1.0f) ;

glEnable(GL_LIGHTING) ;

}and heres the code to initialize the selection mode:

GLvoid MouseFunc(int Button , int State , int x , int y)

{

int Viewport[4] , Hits ;

if(Button == GLUT_LEFT_BUTTON && State == GLUT_DOWN)

{

glGetIntegerv(GL_VIEWPORT , Viewport) ;

glSelectBuffer(512 , ObjectList) ;

glRenderMode(GL_SELECT) ;

//Enter the projection mode, save the matrix and then load the identity.

glMatrixMode(GL_PROJECTION) ;

glPushMatrix() ;

glLoadIdentity() ;

gluPickMatrix((GLdouble)x , (GLdouble)(Viewport[3] - y) , 4 , 4 , Viewport) ;

glOrtho(-6.0f , 6.0f , -6.0f , 6.0f , -400.0f , 400.0f) ;

glMatrixMode(GL_MODELVIEW) ;

DrawGrid(GL_SELECT) ;

//After drawing , pop back the projection matrix and reset to the modelview matrix.

glMatrixMode(GL_PROJECTION) ;

glPopMatrix() ;

glMatrixMode(GL_MODELVIEW) ;

glFlush() ;

Hits = glRenderMode(GL_RENDER) ;

processHits(Hits , ObjectList) ;

glutPostRedisplay() ;

}

}I cant figure out whats wrong..everytime i click on a vertex i get that the no. of hits is zero.

Plz plz help me out...

Thanx

Yours

Siddharth`

I have a problem in picking. I read the tutorials at lighthouse website and i did exactly what they had taught. Well heres my code :

My renderScene code :

GLvoid RenderScene()

{

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) ;

glLoadIdentity() ;

gluLookAt(CameraObj.mPosition.x , CameraObj.mPosition.y , CameraObj.mPosition.z ,

CameraObj.mView.x , CameraObj.mView.y , CameraObj.mView.z ,

CameraObj.mUp.x , CameraObj.mUp.y , CameraObj.mUp.z) ;

//Draw the x , y , z Axis and the grid initially.

DrawAxis() ;

Draw3DGrid() ;

DrawGrid(GL_RENDER) ;

glScalef(0.030f , 0.030f , 0.030f) ;

glRotatef(180.0 , 0.0f , 1.0f , 0.0f) ;

DrawObject() ;

glFlush() ;

glutSwapBuffers() ;

}Heres my DrawGrid code. This is made of points which I must pick...

GLvoid DrawGrid(int mode)

{

if(mode == GL_SELECT)

{

glInitNames();

//glPushName(0);

}

int i , j ;

glDisable(GL_LIGHTING) ;

glPointSize(6.0f) ;

//Draw the line segments

glColor3f(1.0f , 1.0f , 0.0f) ;

for(i = 0 ; i < 8 ; i++)

{

for(j = 0 ; j < 8 ; j++)

{

glBegin(GL_LINE_STRIP) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glVertex3f(ControlPoints[i + 1][j][0] , ControlPoints[i + 1][j][1] , ControlPoints[i + 1][j][2]) ;

glVertex3f(ControlPoints[i + 1][j + 1][0] , ControlPoints[i + 1][j + 1][1] , ControlPoints[i + 1][j + 1][2]) ;

glVertex3f(ControlPoints[i][j + 1][0] , ControlPoints[i][j + 1][1] , ControlPoints[i][j + 1][2]) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glEnd() ;

}

}

//Draw the control vertices.

glColor3f(0.0f , 1.0f , 0.0f) ;

int k = 1 ;

for(i = 0 ; i < 10 ; i++)

{

if(mode == GL_SELECT)

glPushName(i) ;

for(j = 0 ; j < 10 ; j++)

{

if(mode == GL_SELECT)

glPushName(j);

glBegin(GL_POINTS) ;

glVertex3f(ControlPoints[i][j][0] , ControlPoints[i][j][1] , ControlPoints[i][j][2]) ;

glEnd() ;

glPopName() ;

}

glPopName() ;

}

glLineWidth(1.0f) ;

glEnable(GL_LIGHTING) ;

}and heres the code to initialize the selection mode:

GLvoid MouseFunc(int Button , int State , int x , int y)

{

int Viewport[4] , Hits ;

if(Button == GLUT_LEFT_BUTTON && State == GLUT_DOWN)

{

glGetIntegerv(GL_VIEWPORT , Viewport) ;

glSelectBuffer(512 , ObjectList) ;

glRenderMode(GL_SELECT) ;

//Enter the projection mode, save the matrix and then load the identity.

glMatrixMode(GL_PROJECTION) ;

glPushMatrix() ;

glLoadIdentity() ;

gluPickMatrix((GLdouble)x , (GLdouble)(Viewport[3] - y) , 4 , 4 , Viewport) ;

glOrtho(-6.0f , 6.0f , -6.0f , 6.0f , -400.0f , 400.0f) ;

glMatrixMode(GL_MODELVIEW) ;

DrawGrid(GL_SELECT) ;

//After drawing , pop back the projection matrix and reset to the modelview matrix.

glMatrixMode(GL_PROJECTION) ;

glPopMatrix() ;

glMatrixMode(GL_MODELVIEW) ;

glFlush() ;

Hits = glRenderMode(GL_RENDER) ;

processHits(Hits , ObjectList) ;

glutPostRedisplay() ;

}

}I cant figure out whats wrong..everytime i click on a vertex i get that the no. of hits is zero.

Plz plz help me out...

Thanx

Yours

Siddharth`