Get heightmap xyz by mouse

glararan

Hello,

I looking for something what will return xyz position on my terrain.

I used gluUnProject, but it still returning "nan" values

gluUnProject:
@GLint viewport[4];
GLdouble modelview[16], projection[16], posX, posY, posZ;
GLfloat winX, winY, winZ;

   // m_funcs = QOpenGLFunctions_4_1_Core
   m_funcs->glGetIntegerv(GL_VIEWPORT, viewport);
   m_funcs->glGetDoublev(GL_MODELVIEW_MATRIX, modelview);
   m_funcs->glGetDoublev(GL_PROJECTION_MATRIX, projection);

    winX = mouse_position.x();
    winY = static_cast<float>(viewport[3]) - mouse_position.y();

    m_funcs->glReadPixels(winX, winY, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ);
    gluUnProject(winX, winY, winZ, modelview, projection, viewport, &posX, &posY, &posZ);

    terrain_pos = QVector3D(posX, posY, posZ);@

gluUnProject v2:
@GLint viewport[4];
GLdouble modelview[16], projection[16], posX, posY, posZ;
GLfloat winX, winY, winZ;

    int indexing = 0;

    // passing from own Camera class QMatrix4x4 modelView, projection and viewport
    for(int i = 0; i < 4; i++)
    {
        viewport[i] = viewMatrix(0, i);

        for(int j = 0; j < 4; j++)
        {
            modelview[indexing] = modelViewMatrix(i, j);
            projection[indexing] = mvp(i, j);

            indexing++;
        }
    }

    winX = mouse_position.x();
    winY = /*static_cast<float>(viewport[3]) -*/ mouse_position.y();

    m_funcs->glReadPixels(winX, winY, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ);
    gluUnProject(winX, winY, winZ, modelview, projection, viewport, &posX, &posY, &posZ);

    terrain_pos = QVector3D(posX, posY, posZ);@

Every array and params have values in gluUnProject v2, so I don't know why it returns nan :(

Then I tried to use some code from google, but it returns out range positions
@QMatrix4x4 mProjection = m_camera->viewMatrix() * m_camera->projectionMatrix();
QMatrix4x4 mInverse = mProjection.inverted();

    float in[4];
    float winZ = 1.0f;

    in[0] = (2.0f * ((float)(mouse_position.x() - 0) / (this->width() - 0))) - 1.0f,
    in[1] = 1.0f - (2.0f * ((float)(mouse_position.y() - 0) / (this->height() - 0)));
    in[2] = 2.0f * winZ - 1.0f;
    in[3] = 1.0f;

    QVector4D vIn(in[0], in[1], in[2], in[3]);

    QVector4D Vpos = vIn * mInverse;

    Vpos.setW(1.0f / Vpos.w());
    Vpos.setX(Vpos.x() * Vpos.w());
    Vpos.setY(Vpos.y() * Vpos.w());
    Vpos.setZ(Vpos.z() * Vpos.z());

    terrain_pos = QVector3D(Vpos.x(), Vpos.y(), Vpos.z());@

Is any better way to get heightmap xyz in Qt? Or its possible with Qt OpenGL and not with basic GL?

Using QGLWidget with QOpenGL headers and GL version 4.1

Update: Forum Guidelines & Code of Conduct

Qt World Summit: Early-Bird Tickets

Get heightmap xyz by mouse