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sirGustav

OpenGL Problem with quaternion based camera and object placing, possible cml problem

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For months I've been trying to get object and camera placing to work, and it feels like this should work, except that it is missing a character/sign somewhere causing everything to fail

The properties I'm trying to recreate are:
  • In is positive Z
  • Right is positive X
  • Up is positive Y
  • Identity quaternion is facing In/positive z
    This is how I create my projection matrix:
    gluPerspective(camera.fov, aspect, camera.znear, camera.zfar); pwnAssert_NoGLError();

    This is how I build my camera matrix:
    // camera.rotation is a quaternion representing the rotation of the camera, camera.position.vec is the vector of the object
    const math::mat44 fixOpenGlNegativeZ = cmat44(RightHandAround(Up(), Angle::FromDegrees(180)));
    : mat( fixOpenGlNegativeZ * cmat44(camera.rotation) * cmat44(vec3(-X(camera.position.vec), -Y(camera.position.vec), Z(camera.position.vec))) )


    This is how I generate the modelview matrix per object that is sent to gl through LoadMatrix
    // mat is the camera matrix above, pos is the vec3 worldspace position and rot is a quaterion representing the rotation of the object
    return mat * math::cmat44(pos) * math::cmat44(rot)


    My maths is cml based and here are their definitions:
    typedef cml::vector<real, cml::fixed<3> > vec3;
    typedef cml::quaternion<real, cml::fixed<>, cml::vector_first, cml::positive_cross> quat;
    typedef cml::matrix<real, cml::fixed<4,4>, cml::col_basis, cml::col_major > mat44;


    Along cml I have a few wrappers, mainly ©onverter functions beginning with c and ending with the resulting type, like cmat44 converting it's argument to a 4x4 matrix.
    cmat44(vec3) = cml::matrix_set_translation
    cmat44(quat) = cml::matrix_rotation_quaternion
    RightHandAround = cml::quaternion_rotation_axis_angle


    To get right of a quaternion I do:
    // v is global Right(positive X) and q is the quaternion
    const quat r = q * quat(v, 0) * math::GetConjugate(q);
    return cvec3(r); // ignores w
    // the vector is normalized later before it's used


    If anyone can point out what I'm doing wrong or offer suggestions I would be glad :)

    edit: slighty changed topictitle to better describe the problem

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I've might have a working implementation now. I changed fixOpenGlNegativeZ to a negative z scaling matrix since I probably want what is called a left handed coordinate space and the OpenGL faq recommends doing this.
Then I changed my lookat from
quaternion_rotation_aim_at(ret, from, to, up,
cml::axis_order_zyx);

to
cml::matrix_look_at_LH(mat, from, to, up);
cml::quaternion_rotation_matrix(ret,mat);


and that apparently fixed the problems(I still don't know what the difference between those functions are). that I at the moment can detect. I will have to do some more testing but for it seems to be working

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