void gl_select(int x, int y){
GLuint buff[64] = {0};
GLint hits, view[4];
glSelectBuffer(64, buff);
glGetIntegerv(GL_VIEWPORT, view);
glRenderMode(GL_SELECT);
glInitNames();
glPushName(0);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluPickMatrix(x,y,1.0,1.0,view);
gluPerspective(45,1.0,0.0001,1000.0);
glMatrixMode(GL_MODELVIEW);
glutSwapBuffers();
draw();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
hits = glRenderMode(GL_RENDER);
list_hits(hits,buff);
glMatrixMode(GL_MODELVIEW);
}
void GLwidget::mousePressEvent(QMouseEvent *ev)
{
float posX = ev->x();
float posy = ev->y();
GLuint buff[64] = {0};
GLint hits, view[4];
/*
This choose the buffer where store the values for the selection data
*/
glSelectBuffer(64, buff);
/*
This retrieve info about the viewport
*/
glGetIntegerv(GL_VIEWPORT, view);
/*
Switching in selecton mode
*/
glRenderMode(GL_SELECT);
/*
Clearing the name's stack
This stack contains all the info about the objects
*/
glInitNames();
/*
Now fill the stack with one element (or glLoadName will generate an error)
*/
glPushName(0);
/*
Now modify the vieving volume, restricting selection area around the cursor
*/
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
/*
restrict the draw to an area around the cursor
*/
gluPickMatrix(posX, posy, 1.0, 1.0, view);
gluPerspective(60.0, this->width()/this->height(), 0.0001, 1000.0);
/*
Draw the objects onto the screen
*/
glMatrixMode(GL_MODELVIEW);
/*
draw only the names in the stack, and fill the array
*/
//glutSwapBuffers();
swapBuffers();
//gl_draw();
paintGL();
/*
Do you remeber? We do pushMatrix in PROJECTION mode
*/
glMatrixMode(GL_PROJECTION);
glPopMatrix();
/*
get number of objects drawed in that area
and return to render mode
*/
hits = glRenderMode(GL_RENDER);
qDebug() << hits;
/*
Print a list of the objects
*/
list_hits(hits, buff);
/*
uncomment this to show the whole buffer
* /
gl_selall(hits, buff);
*/
glMatrixMode(GL_MODELVIEW);
}
std::vector<Shape3D*> ofEasyFingerCam::glSelect(int x, int y)
{
std::vector<Shape3D*> result = std::vector<Shape3D*>();
GLuint buff[512] = {0};
GLint hits, view[4];
GLfloat proj_matrix[16];
/*
This choose the buffer where store the values for the selection data
*/
glSelectBuffer(256, buff);
/*
This retrieves info about the viewport
*/
glGetIntegerv(GL_VIEWPORT, view);
glGetFloatv(GL_PROJECTION_MATRIX, proj_matrix);
/*
Switching in selecton mode
*/
glRenderMode(GL_SELECT);
/*
Clearing the names' stack
This stack contains all the info about the objects
*/
glInitNames();
/*
Now modify the viewing volume, restricting selection area around the cursor
*/
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
/*
restrict the draw to an area around the cursor
*/
gluPickMatrix(x, ofGetHeight() - y, 15.0, 15.0, view);
float width = ofGetWidth();
float height = ofGetHeight();
float viewW = ofGetViewportWidth();
float viewH = ofGetViewportHeight();
float fov = 60;
float eyeX = viewW / 2;
float eyeY = viewH / 2;
float halfFov = PI * fov / 360;
float theTan = tanf(halfFov);
float dist = eyeY / theTan;
float aspect = (float) viewW / viewH;
float nearDist = dist / 10.0f;
float farDist = dist * 15.0f;
gluPerspective(fov, aspect, nearDist, farDist);
/*
Draw the objects onto the screen
*/
glMatrixMode(GL_MODELVIEW);
/*
draw only the names in the stack, and fill the array
*/
draw();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
/*
get number of objects drawed in that area
and return to render mode
*/
hits = glRenderMode(GL_RENDER);
/*
Print a list of the objects
*/
result = list_hits(hits, buff);
glMatrixMode(GL_MODELVIEW);
return result;
}
