optimized OctreeElement::furthestDistanceToCamera()

libraries/octree/src/OctreeElement.cpp

@@ -1219,14 +1219,13 @@ bool OctreeElement::calculateShouldRender(const ViewFrustum* viewFrustum, float
 }
 
 // Calculates the distance to the furthest point of the voxel to the camera
+// does as much math as possible in voxel scale and then scales up to TREE_SCALE at end
 float OctreeElement::furthestDistanceToCamera(const ViewFrustum& viewFrustum) const {
-    AABox box = getAABox();
-    box.scale(TREE_SCALE);
     glm::vec3 furthestPoint;
-    viewFrustum.getFurthestPointFromCamera(box, furthestPoint);
+    viewFrustum.getFurthestPointFromCameraVoxelScale(getAABox(), furthestPoint);
-    glm::vec3 temp = viewFrustum.getPosition() - furthestPoint;
+    glm::vec3 temp = viewFrustum.getPositionVoxelScale() - furthestPoint;
     float distanceToFurthestPoint = sqrtf(glm::dot(temp, temp));
-    return distanceToFurthestPoint;
+    return distanceToFurthestPoint * (float)TREE_SCALE;
 }
 
 float OctreeElement::distanceToCamera(const ViewFrustum& viewFrustum) const {

libraries/octree/src/ViewFrustum.cpp

@@ -25,6 +25,7 @@ using namespace std;
 
 ViewFrustum::ViewFrustum() :
     _position(0,0,0),
+    _positionVoxelScale(0,0,0),
     _orientation(),
     _direction(IDENTITY_FRONT),
     _up(IDENTITY_UP),
@@ -724,3 +725,31 @@ void ViewFrustum::getFurthestPointFromCamera(const AABox& box, glm::vec3& furthe
         furthestPoint.z = bottomNearRight.z;
     }
 }
+
+void ViewFrustum::getFurthestPointFromCameraVoxelScale(const AABox& box, glm::vec3& furthestPoint) const {
+    const glm::vec3& bottomNearRight = box.getCorner();
+    float scale = box.getScale();
+    float halfScale = scale * 0.5f;
+
+    if (_positionVoxelScale.x < bottomNearRight.x + halfScale) {
+        // we are to the right of the center, so the left edge is furthest
+        furthestPoint.x = bottomNearRight.x + scale;
+    } else {
+        furthestPoint.x = bottomNearRight.x;
+    }
+
+    if (_positionVoxelScale.y < bottomNearRight.y + halfScale) {
+        // we are below of the center, so the top edge is furthest
+        furthestPoint.y = bottomNearRight.y + scale;
+    } else {
+        furthestPoint.y = bottomNearRight.y;
+    }
+
+    if (_positionVoxelScale.z < bottomNearRight.z + halfScale) {
+        // we are to the near side of the center, so the far side edge is furthest
+        furthestPoint.z = bottomNearRight.z + scale;
+    } else {
+        furthestPoint.z = bottomNearRight.z;
+    }
+}
+

libraries/octree/src/ViewFrustum.h

@@ -29,11 +29,12 @@ const float DEFAULT_FAR_CLIP = 50.0f * TREE_SCALE;
 class ViewFrustum {
 public:
     // setters for camera attributes
-    void setPosition(const glm::vec3& p) { _position = p; }
+    void setPosition(const glm::vec3& p) { _position = p; _positionVoxelScale = (p / (float)TREE_SCALE); }
     void setOrientation(const glm::quat& orientationAsQuaternion);
 
     // getters for camera attributes
     const glm::vec3& getPosition() const { return _position; }
+    const glm::vec3& getPositionVoxelScale() const { return _positionVoxelScale; }
     const glm::quat& getOrientation() const { return _orientation; }
     const glm::vec3& getDirection() const { return _direction; }
     const glm::vec3& getUp() const { return _up; }
@@ -102,9 +103,11 @@ public:
 
     glm::vec2 projectPoint(glm::vec3 point, bool& pointInView) const;
     OctreeProjectedPolygon getProjectedPolygon(const AABox& box) const;
-    //glm::vec3 getFurthestPointFromCamera(const AABox& box) const;
     void getFurthestPointFromCamera(const AABox& box, glm::vec3& furthestPoint) const;
     
+    // assumes box is in voxel scale, not TREE_SCALE, will scale view frustum's position accordingly
+    void getFurthestPointFromCameraVoxelScale(const AABox& box, glm::vec3& furthestPoint) const;
+    
 private:
     // Used for keyhole calculations
     ViewFrustum::location pointInKeyhole(const glm::vec3& point) const;
@@ -112,7 +115,8 @@ private:
     ViewFrustum::location boxInKeyhole(const AABox& box) const;
 
     // camera location/orientation attributes
-    glm::vec3   _position;
+    glm::vec3   _position; // the position in TREE_SCALE
+    glm::vec3   _positionVoxelScale; // the position in voxel scale
     glm::quat   _orientation;
 
     // calculated for orientation