Method createBillboardHelper

core/math/Mat4.cpp:184–217

}

void Mat4::createBillboardHelper(const Vec3& objectPosition,
                                 const Vec3& cameraPosition,
                                 const Vec3& cameraUpVector,
                                 const Vec3* cameraForwardVector,
                                 Mat4* dst)
{
    Vec3 delta(objectPosition, cameraPosition);
    bool isSufficientDelta = delta.lengthSquared() > MATH_EPSILON;

    dst->setIdentity();
    dst->m[3]  = objectPosition.x;
    dst->m[7]  = objectPosition.y;
    dst->m[11] = objectPosition.z;

    // As per the contracts for the 2 variants of createBillboard, we need
    // either a safe default or a sufficient distance between object and camera.
    if (cameraForwardVector || isSufficientDelta)
    {
        Vec3 target = isSufficientDelta ? cameraPosition : (objectPosition - *cameraForwardVector);

        // A billboard is the inverse of a lookAt rotation
        Mat4 lookAt;
        createLookAt(objectPosition, target, cameraUpVector, &lookAt);
        dst->m[0]  = lookAt.m[0];
        dst->m[1]  = lookAt.m[4];
        dst->m[2]  = lookAt.m[8];
        dst->m[4]  = lookAt.m[1];
        dst->m[5]  = lookAt.m[5];
        dst->m[6]  = lookAt.m[9];
        dst->m[8]  = lookAt.m[2];
        dst->m[9]  = lookAt.m[6];
        dst->m[10] = lookAt.m[10];
    }
}

// void Mat4::createReflection(const Plane& plane, Mat4* dst)
// {