use hilbert curve instead of flatten array

Using valgrind heap memory tracker, this does not seem to bring any advantage on heap memory usage. To be tested more in depth

include/globals.hpp

@@ -2,6 +2,7 @@
 #define GLOBALS_H
 
 #include "camera.hpp"
+#include "chunk.hpp"
 
 #ifdef GLOBALS_DEFINER
 #define extr
@@ -9,13 +10,13 @@
 #define extr extern
 #endif
 
-#define RENDER_DISTANCE 4
+#define RENDER_DISTANCE 8
 
 extr Camera theCamera;
 
 extr uint32_t MORTON_XYZ_ENCODE[CHUNK_SIZE][CHUNK_SIZE][CHUNK_SIZE];
-extr uint32_t MORTON_XYZ_DECODE[CHUNK_SIZE][3];
+extr uint32_t MORTON_XYZ_DECODE[CHUNK_VOLUME][3];
 extr uint32_t HILBERT_XYZ_ENCODE[CHUNK_SIZE][CHUNK_SIZE][CHUNK_SIZE];
-extr uint32_t HILBERT_XYZ_DECODE[CHUNK_SIZE][3];
+extr uint32_t HILBERT_XYZ_DECODE[CHUNK_VOLUME][3];
 
 #endif

src/chunk.cpp

@@ -27,14 +27,12 @@ namespace Chunk
 
     Block Chunk::getBlock(int x, int y, int z)
     {
-        return blocks.at(coord3DTo1D(x, y, z));
+        return blocks.at(HILBERT_XYZ_ENCODE[x][y][z]);
-        // return blocks.at(HILBERT_XYZ_ENCODE[x][y][z]);
     }
 
     void Chunk::setBlock(Block b, int x, int y, int z)
     {
-        // return blocks.insert(HILBERT_XYZ_ENCODE[x][y][z], HILBERT_XYZ_ENCODE[x][y][z]+1, b);
+        int coord = HILBERT_XYZ_ENCODE[x][y][z];
-        int coord = coord3DTo1D(x, y, z);
         blocks.insert(coord <= 0 ? 0 : coord, coord+1 >= CHUNK_VOLUME ? CHUNK_VOLUME : coord+1, b);
     }
     

src/chunkgenerator.cpp

@@ -4,6 +4,7 @@
 
 #include "block.hpp"
 #include "chunkgenerator.hpp"
+#include "globals.hpp"
 #include "OpenSimplexNoise.h"
 #include "utils.hpp"
 
@@ -43,47 +44,40 @@ void generateNoise(Chunk::Chunk *chunk)
     Block block_prev{Block::AIR};
     int block_prev_start{0};
 
-    // The order of iteration MUST RESPECT the order in which the array is transformed from 3d to 1d
+    // A space filling curve is continuous, so there is no particular order
-    for (int k = 0; k < CHUNK_SIZE; k++)
+    for (int s = 0; s < CHUNK_VOLUME; s++)
     {
-        for (int j = 0; j < CHUNK_SIZE; j++)
+
+        int x = HILBERT_XYZ_DECODE[s][0] + CHUNK_SIZE * chunk->getPosition().x;
+        int y = HILBERT_XYZ_DECODE[s][1] + CHUNK_SIZE * chunk->getPosition().y;
+        int z = HILBERT_XYZ_DECODE[s][2] + CHUNK_SIZE * chunk->getPosition().z;
+        int d2 = HILBERT_XYZ_DECODE[s][0] * CHUNK_SIZE + HILBERT_XYZ_DECODE[s][2];
+
+        if (grassNoiseLUT[d2] == -1)
+            grassNoiseLUT[d2] = GRASS_OFFSET + (int)((0.5 + noiseGen1.eval(x * NOISE_GRASS_X_MULT, z * NOISE_GRASS_Z_MULT) * NOISE_GRASS_MULT));
+        if (dirtNoiseLUT[d2] == -1)
+            dirtNoiseLUT[d2] = NOISE_DIRT_MIN + (int)((0.5 + noiseGen2.eval(x * NOISE_DIRT_X_MULT, z * NOISE_DIRT_Z_MULT) * NOISE_DIRT_MULT));
+
+        int grassNoise = grassNoiseLUT[d2];
+        int dirtNoise = dirtNoiseLUT[d2];
+        int stoneLevel = grassNoise - dirtNoise;
+
+        if (y < stoneLevel)
+            block = Block::STONE;
+        else if (y >= stoneLevel && y < grassNoise)
+            block = Block::DIRT;
+        else if (y == grassNoise)
+            block = Block::GRASS;
+        else
+            block = Block::AIR;
+
+        if (block != block_prev)
         {
-            for (int i = 0; i < CHUNK_SIZE; i++)
+            chunk->setBlocks(block_prev_start, s, block_prev);
-            {
+            block_prev_start = s;
-                int x = i + CHUNK_SIZE * chunk->getPosition().x;
-                int y = j + CHUNK_SIZE * chunk->getPosition().y;
-                int z = k + CHUNK_SIZE * chunk->getPosition().z;
-                int d2 = k * CHUNK_SIZE + i;
-
-                if (grassNoiseLUT[d2] == -1)
-                    grassNoiseLUT[d2] = GRASS_OFFSET + (int)((0.5 + noiseGen1.eval(x * NOISE_GRASS_X_MULT, z * NOISE_GRASS_Z_MULT) * NOISE_GRASS_MULT));
-                if (dirtNoiseLUT[d2] == -1)
-                    dirtNoiseLUT[d2] = NOISE_DIRT_MIN + (int)((0.5 + noiseGen2.eval(x * NOISE_DIRT_X_MULT, z * NOISE_DIRT_Z_MULT) * NOISE_DIRT_MULT));
-
-                int grassNoise = grassNoiseLUT[d2];
-                int dirtNoise = dirtNoiseLUT[d2];
-                int stoneLevel = grassNoise - dirtNoise;
-
-                if (y < stoneLevel)
-                    block = Block::STONE;
-                else if (y >= stoneLevel && y < grassNoise)
-                    block = Block::DIRT;
-                else if (y == grassNoise)
-                    block = Block::GRASS;
-                else
-                    block = Block::AIR;
-
-                int index = Chunk::coord3DTo1D(i, j, k);
-                int min = index > block_prev_start ? block_prev_start : index, max = index > block_prev_start ? index : block_prev_start;
-                if (block != block_prev)
-                {
-                    chunk->setBlocks(block_prev_start, index, block_prev);
-                    block_prev_start = index;
-                }
-
-                block_prev = block;
-            }
         }
+
+        block_prev = block;
     }
 
     chunk->setBlocks(block_prev_start, CHUNK_VOLUME, block_prev);

src/chunkmesh.cpp

@@ -99,10 +99,10 @@ void ChunkMesh::mesh()
                 {
                     for (x[u] = 0; x[u] < CHUNK_SIZE; x[u]++)
                     {
-                        Block b1 = (x[dim] >= 0) ? blocks[Chunk::coord3DTo1D(x[0], x[1], x[2])] : Block::NULLBLK; /*blocks[SpaceFilling::HILBERT_XYZ_ENCODE[x[0]][x[1]][x[2]]]*/
+                        Block b1 = (x[dim] >= 0) ? blocks[HILBERT_XYZ_ENCODE[x[0]][x[1]][x[2]]]: Block::NULLBLK;
                         Block b2 = (x[dim] < CHUNK_SIZE - 1)
-                                       ? blocks[Chunk::coord3DTo1D(x[0] + q[0], x[1] + q[1], x[2] + q[2])]
+                                       ? blocks[HILBERT_XYZ_ENCODE[x[0] + q[0]][x[1] + q[1]][x[2] + q[2]]]
-                                       : Block::NULLBLK; /*blocks[SpaceFilling::HILBERT_XYZ_ENCODE[x[0] + q[0]][x[1] + q[1]][x[2] + q[2]]]*/
+                                       : Block::NULLBLK; 
 
                         // This is the original line taken from rob's code, readapted (replace voxelFace
                         // with b1 and b2).

src/main.cpp

@@ -51,7 +51,7 @@ int main()
     glfwSetCursorPosCallback(window, mouse_callback);
     glEnable(GL_DEPTH_TEST);
 
-    // SpaceFilling::initLUT();
+    SpaceFilling::initLUT();
     chunkmanager::init();
 
     while (!glfwWindowShouldClose(window))

src/spacefilling.cpp

@@ -188,15 +188,16 @@ namespace SpaceFilling
 
     void initLUT()
     {
-        uint32_t morton, hilbert;
+        uint32_t morton, hilbert,j;
         for (uint32_t i = 0; i < CHUNK_SIZE; i++)
         {
-            for (uint32_t j = 0; j < CHUNK_SIZE; j++)
+            for (uint32_t y = 0; y < CHUNK_SIZE; y++)
             {
                 for (uint32_t k = 0; k < CHUNK_SIZE; k++)
                 {
+                    j = CHUNK_SIZE - 1 - y;
                     morton = Morton_3D_Encode_10bit(i, j, k);
-                    hilbert = MortonToHilbert3D(morton, 4); // 4 hilbert bits
+                    hilbert = MortonToHilbert3D(morton, 2); // 4 hilbert bits
 
                     MORTON_XYZ_ENCODE[i][j][k] = morton;
                     MORTON_XYZ_DECODE[morton][0] = i;