Fix wrong Z check in OgreWideAngleCamera::Project3d (#746)

The matrix returned by Ogre::Camera::getProjectionMatrix has Z in range
[-1; 1], not range [0; 1]

This means we can't do pos.z > 0. We must do pos.z / pos.w > -1
Additionally, we must check against against z < 1; otherwise the point
may get picked by the wrong face (and fail tests).

Signed-off-by: Matias N. Goldberg <dark_sylinc@yahoo.com.ar>

ogre/src/OgreWideAngleCamera.cc

@@ -505,8 +505,11 @@ math::Vector3d OgreWideAngleCamera::Project3d(
     auto pos = viewProj * Ogre::Vector4(OgreConversions::Convert(_pt));
     pos.x /= pos.w;
     pos.y /= pos.w;
-    // check if point is visible
-    if (std::fabs(pos.x) <= 1 && std::fabs(pos.y) <= 1 && pos.z > 0)
+    // check if point is visible.
+    // pos.z is in range [-w; w] so we check if it's > -w then
+    // it means it's in front of us.
+    if (std::fabs(pos.x) <= 1 && std::fabs(pos.y) <= 1 &&
+        pos.z > -std::fabs(pos.w))
     {
       // determine dir vector to projected point from env camera
       // work in y up, z forward, x right clip space