Merge pull request #517 from PhilipRosedale/master

Added voxel system physical 'density' for better/correct appearance of objects at distance

libraries/voxels/src/VoxelNode.cpp

@@ -35,7 +35,7 @@ void VoxelNode::init(unsigned char * octalCode) {
     _currentColor[0] = _currentColor[1] = _currentColor[2] = _currentColor[3] = 0;
 #endif
     _trueColor[0] = _trueColor[1] = _trueColor[2] = _trueColor[3] = 0;
-
+    _density = 0.0f;
     
     // default pointers to child nodes to NULL
     for (int i = 0; i < NUMBER_OF_CHILDREN; i++) {
@@ -161,10 +161,10 @@ void VoxelNode::safeDeepDeleteChildAtIndex(int childIndex, bool& stagedForDeleti
     }
 }
 
-
 // will average the child colors...
 void VoxelNode::setColorFromAverageOfChildren() {
     int colorArray[4] = {0,0,0,0};
+    float density = 0.0f;
     for (int i = 0; i < NUMBER_OF_CHILDREN; i++) {
         if (_children[i] && !_children[i]->isStagedForDeletion() && _children[i]->isColored()) {
             for (int j = 0; j < 3; j++) {
@@ -172,11 +172,24 @@ void VoxelNode::setColorFromAverageOfChildren() {
             }
             colorArray[3]++;
         }
+        if (_children[i]) {
+            density += _children[i]->getDensity();
+        }
     }
+    density /= (float) NUMBER_OF_CHILDREN;    
+    //
+    //  The VISIBLE_ABOVE_DENSITY sets the density of matter above which an averaged color voxel will
+    //  be set.  It is an important physical constant in our universe.  A number below 0.5 will cause
+    //  things to get 'fatter' at a distance, because upward averaging will make larger voxels out of
+    //  less data, which is (probably) going to be preferable because it gives a sense that there is
+    //  something out there to go investigate.   A number above 0.5 would cause the world to become
+    //  more 'empty' at a distance.  Exactly 0.5 would match the physical world, at least for materials
+    //  that are not shiny and have equivalent ambient reflectance.  
+    //
+    const float VISIBLE_ABOVE_DENSITY = 0.10f;        
     nodeColor newColor = { 0, 0, 0, 0};
-    if (colorArray[3] > 4) {
-        // we need at least 4 colored children to have an average color value
-        // or if we have none we generate random values
+    if (density > VISIBLE_ABOVE_DENSITY) {
+        // The density of material in the space of the voxel sets whether it is actually colored
         for (int c = 0; c < 3; c++) {
             // set the average color value
             newColor[c] = colorArray[c] / colorArray[3];
@@ -184,10 +197,9 @@ void VoxelNode::setColorFromAverageOfChildren() {
         // set the alpha to 1 to indicate that this isn't transparent
         newColor[3] = 1;
     }
-    // actually set our color, note, if we didn't have enough children
-    // this will be the default value all zeros, and therefore be marked as
-    // transparent with a 4th element of 0
+    //  Set the color from the average of the child colors, and update the density 
     setColor(newColor);
+    setDensity(density);
 }
 
 // Note: !NO_FALSE_COLOR implementations of setFalseColor(), setFalseColored(), and setColor() here.
@@ -214,20 +226,21 @@ void VoxelNode::setFalseColored(bool isFalseColored) {
         _falseColored = isFalseColored; 
         _isDirty = true;
         markWithChangedTime();
+        _density = 1.0f;       //   If color set, assume leaf, re-averaging will update density if needed.
+
     }
 };
 
 
 void VoxelNode::setColor(const nodeColor& color) {
     if (_trueColor[0] != color[0] || _trueColor[1] != color[1] || _trueColor[2] != color[2]) {
-        //printLog("VoxelNode::setColor() was: (%d,%d,%d) is: (%d,%d,%d)\n",
-        //    _trueColor[0],_trueColor[1],_trueColor[2],color[0],color[1],color[2]);
         memcpy(&_trueColor,&color,sizeof(nodeColor));
         if (!_falseColored) {
             memcpy(&_currentColor,&color,sizeof(nodeColor));
         }
         _isDirty = true;
         markWithChangedTime();
+        _density = 1.0f;       //   If color set, assume leaf, re-averaging will update density if needed.
     }
 }
 #endif

libraries/voxels/src/VoxelNode.h

@@ -36,6 +36,7 @@ private:
     unsigned char* _octalCode;
     VoxelNode* _children[8];
     int _childCount;
+    float _density;             // If leaf: density = 1, if internal node: 0-1 density of voxels inside
 
     void calculateAABox();
 
@@ -102,11 +103,14 @@ public:
     void setColor(const nodeColor& color);
     const nodeColor& getTrueColor() const { return _trueColor; };
     const nodeColor& getColor() const { return _currentColor; };
+    void setDensity(const float density) { _density = density; };
+    const float getDensity() const { return _density; };
 #else
     void setFalseColor(colorPart red, colorPart green, colorPart blue) { /* no op */ };
     void setFalseColored(bool isFalseColored) { /* no op */ };
     bool getFalseColored() { return false; };
     void setColor(const nodeColor& color) { memcpy(_trueColor,color,sizeof(nodeColor)); };
+    void setDensity(const float density) { _density = density; };
     const nodeColor& getTrueColor() const { return _trueColor; };
     const nodeColor& getColor() const { return _trueColor; };
 #endif

voxel-server/src/main.cpp

@@ -387,16 +387,6 @@ void persistVoxelsWhenDirty() {
 
     // check the dirty bit and persist here...
     if (::wantVoxelPersist && ::serverTree.isDirty() && sinceLastTime > VOXEL_PERSIST_INTERVAL) {
-
-        {
-            PerformanceWarning warn(::shouldShowAnimationDebug, 
-                                    "persistVoxelsWhenDirty() - reaverageVoxelColors()", ::shouldShowAnimationDebug);
-
-            // after done inserting all these voxels, then reaverage colors
-            serverTree.reaverageVoxelColors(serverTree.rootNode);
-        }
-
-
         {
             PerformanceWarning warn(::shouldShowAnimationDebug, 
                                     "persistVoxelsWhenDirty() - writeToSVOFile()", ::shouldShowAnimationDebug);
@@ -506,6 +496,15 @@ int main(int argc, const char * argv[]) {
     if (::wantVoxelPersist) {
         printf("loading voxels from file...\n");
         persistantFileRead = ::serverTree.readFromSVOFile(::wantLocalDomain ? LOCAL_VOXELS_PERSIST_FILE : VOXELS_PERSIST_FILE);
+        if (persistantFileRead) {
+            PerformanceWarning warn(::shouldShowAnimationDebug,
+                                    "persistVoxelsWhenDirty() - reaverageVoxelColors()", ::shouldShowAnimationDebug);
+            
+            // after done inserting all these voxels, then reaverage colors
+            serverTree.reaverageVoxelColors(serverTree.rootNode);
+            printf("Voxels reAveraged\n");
+        }
+        
         ::serverTree.clearDirtyBit(); // the tree is clean since we just loaded it
         printf("DONE loading voxels from file... fileRead=%s\n", debug::valueOf(persistantFileRead));
         unsigned long nodeCount = ::serverTree.getVoxelCount();