sumaia

09-13-2015, 08:06 AM

hello ,

i am very new in openGL, i have faced many problems while i was drawing and selecting and moving objects in 3D

first for selection , i faced a problem then it was solved correctly using processHits way (selection mode ) ,then i moved to the camera , and also it was done correctly , then one thing is left ,

moving the selected object , whatever the camera position is ...

let's suppose we have a vertex v, its current position is :

v.x,v.y,v.z

we select the vertex and we want to move it (of course i am not talking about vertex suppose it is a sphere and v is its center )

now we we move the mouse by dy, and dx, (dy =newmouseposition.y -oldmouseposition.y) and (dx =newmouseposition.x -oldmouseposition.x)

i want to move the object on plane XY

so if i did it this way :

v.x=v.x+dx ;

v.y=v.y+dy;

that is not totally okay cuz after moving a camera with some movements may be the x axis will be on vertical and y for horizantal or the become in an opposite way

i moved to raycast way ,but ait didnt work :

glm::vec3 myglwidget::raycast(int mouse_x, int mouse_y)

{

GLint viewport[4];

GLdouble modelview[16];

GLdouble projection[16];

GLfloat winX, winY, winZ;

GLdouble posX, posY, posZ;

glGetDoublev( GL_MODELVIEW_MATRIX, modelview );

glGetDoublev( GL_PROJECTION_MATRIX, projection );

glGetIntegerv( GL_VIEWPORT, viewport );

winX = (float)mouse_x;

winY = (float)viewport[3] - (float)mouse_y;

glReadPixels( mouse_x, int(winY), 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ );

gluUnProject( winX, winY, winZ, modelview, projection, viewport, &posX, &posY, &posZ);

return glm::vec3(posX, posY, posZ);

}

so what is the solution for this kind of movement ?

i am very new in openGL, i have faced many problems while i was drawing and selecting and moving objects in 3D

first for selection , i faced a problem then it was solved correctly using processHits way (selection mode ) ,then i moved to the camera , and also it was done correctly , then one thing is left ,

moving the selected object , whatever the camera position is ...

let's suppose we have a vertex v, its current position is :

v.x,v.y,v.z

we select the vertex and we want to move it (of course i am not talking about vertex suppose it is a sphere and v is its center )

now we we move the mouse by dy, and dx, (dy =newmouseposition.y -oldmouseposition.y) and (dx =newmouseposition.x -oldmouseposition.x)

i want to move the object on plane XY

so if i did it this way :

v.x=v.x+dx ;

v.y=v.y+dy;

that is not totally okay cuz after moving a camera with some movements may be the x axis will be on vertical and y for horizantal or the become in an opposite way

i moved to raycast way ,but ait didnt work :

glm::vec3 myglwidget::raycast(int mouse_x, int mouse_y)

{

GLint viewport[4];

GLdouble modelview[16];

GLdouble projection[16];

GLfloat winX, winY, winZ;

GLdouble posX, posY, posZ;

glGetDoublev( GL_MODELVIEW_MATRIX, modelview );

glGetDoublev( GL_PROJECTION_MATRIX, projection );

glGetIntegerv( GL_VIEWPORT, viewport );

winX = (float)mouse_x;

winY = (float)viewport[3] - (float)mouse_y;

glReadPixels( mouse_x, int(winY), 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ );

gluUnProject( winX, winY, winZ, modelview, projection, viewport, &posX, &posY, &posZ);

return glm::vec3(posX, posY, posZ);

}

so what is the solution for this kind of movement ?