Prevent floating point over- and underflows; specifically when interpolating the camera position (closes #575)

modules/atmosphere/rendering/atmospheredeferredcaster.cpp

@@ -292,7 +292,13 @@ void AtmosphereDeferredcaster::preRaycast(const RenderData& renderData,
             }
 
             // Sun Position in Object Space
-            program.setUniform(_uniformCache2.sunDirectionObj, glm::normalize(glm::dvec3(sunPosObj)));
+            const double l = glm::length(glm::dvec3(sunPosObj));
+            program.setUniform(
+                _uniformCache2.sunDirectionObj,
+                l > 0.0 ?
+                glm::normalize(glm::dvec3(sunPosObj)) :
+                glm::dvec3(0.0)
+            );
 
             // Shadow calculations..
             if (!_shadowConfArray.empty()) {

modules/globebrowsing/chunk/culling/horizonculler.cpp

@@ -85,13 +85,21 @@ bool HorizonCuller::isCullable(const glm::dvec3& cameraPosition,
                                double objectBoundingSphereRadius,
                                double minimumGlobeRadius)
 {
-    double distanceToHorizon =
-        sqrt(pow(length(cameraPosition - globePosition), 2) -
-        pow(minimumGlobeRadius, 2));
+    const double objectP = pow(length(objectPosition - globePosition), 2);
+    const double horizonP = pow(minimumGlobeRadius - objectBoundingSphereRadius, 2);
+    if (objectP < horizonP) {
+        return false;
+    }
 
-    double minimumAllowedDistanceToObjectFromHorizon = sqrt(
-        pow(length(objectPosition - globePosition), 2) -
-        pow(minimumGlobeRadius - objectBoundingSphereRadius, 2));
+    const double cameraP = pow(length(cameraPosition - globePosition), 2);
+    const double minR = pow(minimumGlobeRadius, 2);
+    if (cameraP < minR) {
+        return false;
+    }
+
+
+    double minimumAllowedDistanceToObjectFromHorizon = sqrt(objectP - horizonP);
+    double distanceToHorizon = sqrt(cameraP - minR);
 
     // Minimum allowed for the object to be occluded
     double minimumAllowedDistanceToObjectSquared =

modules/globebrowsing/rendering/chunkrenderer.cpp

@@ -271,8 +271,11 @@ void ChunkRenderer::setCommonUniforms(ghoul::opengl::ProgramObject& programObjec
         chunk.owner().generalProperties().atmosphereEnabled ||
         chunk.owner().generalProperties().performShading)
     {
-        glm::vec3 directionToSunWorldSpace =
-            glm::normalize(-data.modelTransform.translation);
+        glm::dvec3 directionToSunWorldSpace =
+            length(data.modelTransform.translation) > 0.0 ?
+            glm::normalize(-data.modelTransform.translation) :
+            glm::dvec3(0.0);
+
         glm::vec3 directionToSunCameraSpace =
             glm::vec3(viewTransform * glm::dvec4(directionToSunWorldSpace, 0));
         programObject.setUniform(