X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Fvoxel.cpp;h=1299a5296da9c5eef0d25e243b6f2ca721f5e052;hb=7289d61e99625b46eb2c4d6b90a2a5de42f207e6;hp=19f2deb3279445e51d7e3b3ab95f77761c6c6f28;hpb=8ad83767cfccc2d1a42bdc4af087ec013d7554a0;p=minetest.git

diff --git a/src/voxel.cpp b/src/voxel.cpp
index 19f2deb32..1299a5296 100644
--- a/src/voxel.cpp
+++ b/src/voxel.cpp
@@ -46,21 +46,15 @@ VoxelManipulator::VoxelManipulator():
 VoxelManipulator::~VoxelManipulator()
 {
 	clear();
-	if(m_data)
-		delete[] m_data;
-	if(m_flags)
-		delete[] m_flags;
 }
 
 void VoxelManipulator::clear()
 {
 	// Reset area to volume=0
 	m_area = VoxelArea();
-	if(m_data)
-		delete[] m_data;
+	delete[] m_data;
 	m_data = NULL;
-	if(m_flags)
-		delete[] m_flags;
+	delete[] m_flags;
 	m_flags = NULL;
 }
 
@@ -142,7 +136,7 @@ void VoxelManipulator::print(std::ostream &o, INodeDefManager *ndef,
 	}
 }
 
-void VoxelManipulator::addArea(VoxelArea area)
+void VoxelManipulator::addArea(const VoxelArea &area)
 {
 	// Cancel if requested area has zero volume
 	if(area.getExtent() == v3s16(0,0,0))
@@ -180,7 +174,9 @@ void VoxelManipulator::addArea(VoxelArea area)
 	dstream<<std::endl;*/
 
 	// Allocate and clear new data
-	MapNode *new_data = new MapNode[new_size];
+	// FIXME: UGLY KLUDGE because MapNode default constructor is FUBAR; it
+	//        initialises data that is going to be overwritten anyway
+	MapNode *new_data = (MapNode*)new char[new_size * sizeof (*new_data)];
 	assert(new_data);
 	u8 *new_flags = new u8[new_size];
 	assert(new_flags);
@@ -213,10 +209,8 @@ void VoxelManipulator::addArea(VoxelArea area)
 	m_data = new_data;
 	m_flags = new_flags;
 
-	if(old_data)
-		delete[] old_data;
-	if(old_flags)
-		delete[] old_flags;
+	delete[] old_data;
+	delete[] old_flags;
 
 	//dstream<<"addArea done"<<std::endl;
 }
@@ -224,13 +218,48 @@ void VoxelManipulator::addArea(VoxelArea area)
 void VoxelManipulator::copyFrom(MapNode *src, const VoxelArea& src_area,
 		v3s16 from_pos, v3s16 to_pos, v3s16 size)
 {
-	for(s16 z=0; z<size.Z; z++)
-	for(s16 y=0; y<size.Y; y++)
-	{
-		s32 i_src = src_area.index(from_pos.X, from_pos.Y+y, from_pos.Z+z);
-		s32 i_local = m_area.index(to_pos.X, to_pos.Y+y, to_pos.Z+z);
-		memcpy(&m_data[i_local], &src[i_src], size.X*sizeof(MapNode));
-		memset(&m_flags[i_local], 0, size.X);
+	/* The reason for this optimised code is that we're a member function
+	 * and the data type/layout of m_data is know to us: it's stored as
+	 * [z*h*w + y*h + x]. Therefore we can take the calls to m_area index
+	 * (which performs the preceding mapping/indexing of m_data) out of the
+	 * inner loop and calculate the next index as we're iterating to gain
+	 * performance.
+	 *
+	 * src_step and dest_step is the amount required to be added to our index
+	 * every time y increments. Because the destination area may be larger
+	 * than the source area we need one additional variable (otherwise we could
+	 * just continue adding dest_step as is done for the source data): dest_mod.
+	 * dest_mod is the difference in size between a "row" in the source data
+	 * and a "row" in the destination data (I am using the term row loosely
+	 * and for illustrative purposes). E.g.
+	 *
+	 * src       <-------------------->|'''''' dest mod ''''''''
+	 * dest      <--------------------------------------------->
+	 *
+	 * dest_mod (it's essentially a modulus) is added to the destination index
+	 * after every full iteration of the y span.
+	 *
+	 * This method falls under the category "linear array and incrementing
+	 * index".
+	 */
+
+	s32 src_step = src_area.getExtent().X;
+	s32 dest_step = m_area.getExtent().X;
+	s32 dest_mod = m_area.index(to_pos.X, to_pos.Y, to_pos.Z + 1)
+			- m_area.index(to_pos.X, to_pos.Y, to_pos.Z)
+			- dest_step * size.Y;
+
+	s32 i_src = src_area.index(from_pos.X, from_pos.Y, from_pos.Z);
+	s32 i_local = m_area.index(to_pos.X, to_pos.Y, to_pos.Z);
+
+	for (s16 z = 0; z < size.Z; z++) {
+		for (s16 y = 0; y < size.Y; y++) {
+			memcpy(&m_data[i_local], &src[i_src], size.X * sizeof(*m_data));
+			memset(&m_flags[i_local], 0, size.X);
+			i_src += src_step;
+			i_local += dest_step;
+		}
+		i_local += dest_mod;
 	}
 }
 
@@ -310,7 +339,8 @@ void VoxelManipulator::unspreadLight(enum LightBank bank, v3s16 p, u8 oldlight,
 		v3s16(-1,0,0), // left
 	};
 
-	addArea(VoxelArea(p - v3s16(1,1,1), p + v3s16(1,1,1)));
+	VoxelArea voxel_area(p - v3s16(1,1,1), p + v3s16(1,1,1));
+	addArea(voxel_area);
 
 	// Loop through 6 neighbors
 	for(u16 i=0; i<6; i++)
@@ -384,7 +414,7 @@ void VoxelManipulator::unspreadLight(enum LightBank bank,
 		std::map<v3s16, u8> & from_nodes,
 		std::set<v3s16> & light_sources, INodeDefManager *nodemgr)
 {
-	if(from_nodes.size() == 0)
+	if(from_nodes.empty())
 		return;
 
 	for(std::map<v3s16, u8>::iterator j = from_nodes.begin();
@@ -515,7 +545,8 @@ void VoxelManipulator::spreadLight(enum LightBank bank, v3s16 p,
 		v3s16(-1,0,0), // left
 	};
 
-	addArea(VoxelArea(p - v3s16(1,1,1), p + v3s16(1,1,1)));
+	VoxelArea voxel_area(p - v3s16(1,1,1), p + v3s16(1,1,1));
+	addArea(voxel_area);
 
 	u32 i = m_area.index(p);
 
@@ -609,7 +640,7 @@ void VoxelManipulator::spreadLight(enum LightBank bank,
 		v3s16(-1,0,0), // left
 	};
 
-	if(from_nodes.size() == 0)
+	if(from_nodes.empty())
 		return;
 
 	std::set<v3s16> lighted_nodes;
@@ -619,7 +650,8 @@ void VoxelManipulator::spreadLight(enum LightBank bank,
 	{
 		v3s16 pos = *j;
 
-		addArea(VoxelArea(pos - v3s16(1,1,1), pos + v3s16(1,1,1)));
+		VoxelArea voxel_area(pos - v3s16(1,1,1), pos + v3s16(1,1,1));
+		addArea(voxel_area);
 
 		u32 i = m_area.index(pos);
 
@@ -681,7 +713,7 @@ void VoxelManipulator::spreadLight(enum LightBank bank,
 			<<" for "<<from_nodes.size()<<" nodes"
 			<<std::endl;*/
 
-	if(lighted_nodes.size() > 0)
+	if(!lighted_nodes.empty())
 		spreadLight(bank, lighted_nodes, nodemgr);
 }
 #endif