generator: add comments + a bit of refactor
EmaMaker
parent
baa8d14bb3
commit
b0cf413baf
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@ -1,7 +1,6 @@
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#include <array>
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#include <iostream>
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#include <random> // for std::mt19937
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#include <experimental/random>
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#include "block.hpp"
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#include "chunkgenerator.hpp"
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@ -23,14 +22,16 @@
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#define LEAVES_RADIUS 3
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#define WOOD_CELL_SIZE 13
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#define WOOD_CELL_CENTER 7
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#define WOOD_CELL_BORDER (LEAVES_RADIUS-1)
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#define WOOD_MAX_OFFSET (WOOD_CELL_SIZE-WOOD_CELL_CENTER-WOOD_CELL_BORDER)
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#define TREE_STANDARD_HEIGHT 7
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#define TREE_HEIGHT_VARIATION 2
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#define WOOD_CELL_BORDER (LEAVES_RADIUS-1)
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#define WOOD_MAX_OFFSET (WOOD_CELL_SIZE-WOOD_CELL_CENTER-WOOD_CELL_BORDER)
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void generatePyramid(Chunk::Chunk *chunk);
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void generateNoise(Chunk::Chunk *chunk);
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void generateNoise3D(Chunk::Chunk *chunk);
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double evaluateNoise(OpenSimplexNoise::Noise noiseGen, double x, double y, double amplitude, double
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frequency, double persistence, double lacunarity, int octaves);
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struct TreeCellInfo evaluateTreeCell(int wcx, int wcz);
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std::random_device dev;
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std::mt19937 mt(dev());
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@ -38,6 +39,9 @@ OpenSimplexNoise::Noise noiseGen1(mt());
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OpenSimplexNoise::Noise noiseGen2(mt());
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OpenSimplexNoise::Noise noiseGenWood(mt());
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// Trees are generated by virtually dividing the world into cells. Each cell can contain exactly one
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// tree, with some offset in the position. Having a border in the cell ensures that no trees are generated in
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// adjacent blocks
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// cover CHUNK_SIZE with WOOD_CELLS + 2 cells before and after the chunk
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constexpr int TREE_LUT_SIZE = std::ceil(static_cast<float>(CHUNK_SIZE)/static_cast<float>(WOOD_CELL_SIZE)) + 2;
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// Info on the tree cell to generate
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@ -45,73 +49,31 @@ struct TreeCellInfo{
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// Cell coordinates (in "tree cell space")
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int wcx, wcz;
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// trunk offset from 0,0 in the cell
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int wcx_offset, wcz_offset;
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int trunk_x_offset, trunk_z_offset;
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// Global x,z position of the trunk
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int wx, wz;
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int trunk_x, trunk_z;
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// Y of the center of the leaves sphere
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int leaves_y_pos;
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};
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// Lookup tables for generation
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std::array<int, CHUNK_SIZE * CHUNK_SIZE> grassNoiseLUT;
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std::array<int, CHUNK_SIZE * CHUNK_SIZE> dirtNoiseLUT;
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std::array<TreeCellInfo, TREE_LUT_SIZE*TREE_LUT_SIZE> treeLUT;
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void generateChunk(Chunk::Chunk *chunk)
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{
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generateNoise(chunk);
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}
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double evaluateNoise(OpenSimplexNoise::Noise noiseGen, double x, double y, double amplitude, double
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frequency, double persistence, double lacunarity, int octaves){
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double sum = 0;
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for(int i = 0; i < octaves; i++){
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sum += amplitude * noiseGen.eval(x*frequency, y*frequency);
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amplitude *= persistence;
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frequency *= lacunarity;
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}
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return sum;
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}
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const int TREE_MASTER_SEED_X = mt();
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const int TREE_MASTER_SEED_Z = mt();
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struct TreeCellInfo evaluateTreeCell(int wcx, int wcz){
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int anglex = TREE_MASTER_SEED_X*wcx+TREE_MASTER_SEED_Z*wcz;
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int anglez = TREE_MASTER_SEED_Z*wcz+TREE_MASTER_SEED_X*wcx;
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// Start at the center of the cell, with a bit of random offset
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int wcx_off = WOOD_CELL_CENTER + WOOD_MAX_OFFSET * sines[anglex % 360];
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int wcz_off = WOOD_CELL_CENTER + WOOD_MAX_OFFSET * cosines[anglez % 360];
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struct TreeCellInfo result{};
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// Cell to world coordinates
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result.wx = wcx * WOOD_CELL_SIZE + wcx_off;
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result.wz = wcz * WOOD_CELL_SIZE + wcz_off;
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result.wcx_offset = wcx_off;
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result.wcz_offset = wcz_off;
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result.leaves_y_pos = 1 + TREE_STANDARD_HEIGHT + GRASS_OFFSET + evaluateNoise(noiseGen1,
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result.wx, result.wz, NOISE_GRASS_MULT, 0.01, 0.35, 2.1, 5);
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return result;
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}
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void generateNoise(Chunk::Chunk *chunk)
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{
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Block block;
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int cx = chunk->getPosition().x * CHUNK_SIZE;
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int cy = chunk->getPosition().y * CHUNK_SIZE;
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int cz = chunk->getPosition().z * CHUNK_SIZE;
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// Precalculate LUTs
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// Terrain LUTs
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// Noise value at a given (x,z), position represents:
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// Grass Noise LUT: Height of the terrain: when the grass is placed and the player will stand
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// Dirt Noise LUT: How many blocks of dirt to place before there is stone
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// Anything below (grass-level - dirt_height) will be stone
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for (int i = 0; i < grassNoiseLUT.size(); i++)
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{
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int bx = i / CHUNK_SIZE;
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@ -135,10 +97,11 @@ void generateNoise(Chunk::Chunk *chunk)
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// Generation of terrain
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Block block_prev{Block::AIR};
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// March along the space-filling curve, calculate information about the block at every position
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// A space-filling curve is continuous, so there is no particular order
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// Take advantage of the interval-map structure by only inserting contigous runs of blocks
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Block block_prev{Block::AIR}, block;
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int block_prev_start{0};
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// A space filling curve is continuous, so there is no particular order
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for (int s = 0; s < CHUNK_VOLUME; s++)
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{
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int bx = HILBERT_XYZ_DECODE[s][0];
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@ -147,10 +110,10 @@ void generateNoise(Chunk::Chunk *chunk)
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int x = bx + cx;
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int y = by + cy;
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int z = bz + cz;
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int d2 = bx * CHUNK_SIZE + bz;
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int lut_index = bx * CHUNK_SIZE + bz;
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int grassNoise = grassNoiseLUT[d2];
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int dirtNoise = dirtNoiseLUT[d2];
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int grassNoise = grassNoiseLUT[lut_index];
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int dirtNoise = dirtNoiseLUT[lut_index];
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int stoneLevel = grassNoise - dirtNoise;
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if (y < stoneLevel)
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@ -165,47 +128,49 @@ void generateNoise(Chunk::Chunk *chunk)
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// Divide the world into cells, each with exactly one tree, so that no two trees will be adjacent of each other
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struct TreeCellInfo info;
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int wcx = (int)(x / WOOD_CELL_SIZE) - tree_lut_x_offset;
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int wcz = (int)(z / WOOD_CELL_SIZE) - tree_lut_z_offset;
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int wcx = (int)(x / WOOD_CELL_SIZE) - tree_lut_x_offset; // wood cell x
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int wcz = (int)(z / WOOD_CELL_SIZE) - tree_lut_z_offset; // wood cell z
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// Retrieve info on the cell from LUT
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info = treeLUT[wcx * TREE_LUT_SIZE + wcz];
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// A tree is to be placed in this position if the coordinates are those of the tree of the current cell
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int wood_height = TREE_STANDARD_HEIGHT;
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bool wood = x == info.wx && z == info.wz && y > grassNoiseLUT[d2] && y <= info.leaves_y_pos;
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bool wood = x == info.trunk_x && z == info.trunk_z && y > grassNoiseLUT[lut_index] && y <= info.leaves_y_pos;
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bool leaf{false};
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// Check placing of leaves
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if(wood) leaf = y > info.leaves_y_pos && y < info.leaves_y_pos+LEAVES_RADIUS;
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else{
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if(!leaf) leaf = utils::withinDistance(x,y,z, info.wx, info.leaves_y_pos, info.wz, LEAVES_RADIUS);
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if(!leaf) leaf = utils::withinDistance(x,y,z, info.trunk_x, info.leaves_y_pos, info.trunk_z, LEAVES_RADIUS);
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// Eventually search neighboring cells
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if(!leaf && wcx+1 < TREE_LUT_SIZE){
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info = treeLUT[(wcx+1) * TREE_LUT_SIZE + wcz];
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leaf = utils::withinDistance(x,y,z, info.wx, info.leaves_y_pos, info.wz, LEAVES_RADIUS);
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leaf = utils::withinDistance(x,y,z, info.trunk_x, info.leaves_y_pos, info.trunk_z, LEAVES_RADIUS);
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}
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if(!leaf && wcx-1 >= 0){
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info = treeLUT[(wcx-1) * TREE_LUT_SIZE + wcz];
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leaf = utils::withinDistance(x,y,z, info.wx, info.leaves_y_pos, info.wz, LEAVES_RADIUS);
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leaf = utils::withinDistance(x,y,z, info.trunk_x, info.leaves_y_pos, info.trunk_z, LEAVES_RADIUS);
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}
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if(!leaf && wcz-1 >= 0){
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info = treeLUT[wcx * TREE_LUT_SIZE + (wcz-1)];
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leaf = utils::withinDistance(x,y,z, info.wx, info.leaves_y_pos, info.wz, LEAVES_RADIUS);
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leaf = utils::withinDistance(x,y,z, info.trunk_x, info.leaves_y_pos, info.trunk_z, LEAVES_RADIUS);
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}
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if(!leaf && wcz+1 < TREE_LUT_SIZE){
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info = treeLUT[wcx * TREE_LUT_SIZE + (wcz+1)];
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leaf = utils::withinDistance(x,y,z, info.wx, info.leaves_y_pos, info.wz, LEAVES_RADIUS);
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leaf = utils::withinDistance(x,y,z, info.trunk_x, info.leaves_y_pos, info.trunk_z, LEAVES_RADIUS);
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}
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}
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if(wood) block = Block::WOOD;
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if(leaf) block = Block::LEAVES;
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// Use the interval-map structure of the chunk to compress the world: insert "runs" of
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// equal blocks using indices in the hilbert curve
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if (block != block_prev)
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{
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chunk->setBlocks(block_prev_start, s, block_prev);
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@ -213,12 +178,60 @@ void generateNoise(Chunk::Chunk *chunk)
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}
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block_prev = block;
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}
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// Insert the last run of blocks
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chunk->setBlocks(block_prev_start, CHUNK_VOLUME, block_prev);
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// Mark the chunk as generated, is needed to trigger the next steps
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chunk->setState(Chunk::CHUNK_STATE_GENERATED, true);
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}
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// Noise evaluation with Fractal Brownian Motion
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double evaluateNoise(OpenSimplexNoise::Noise noiseGen, double x, double y, double amplitude, double
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frequency, double persistence, double lacunarity, int octaves){
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double sum = 0;
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for(int i = 0; i < octaves; i++){
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sum += amplitude * noiseGen.eval(x*frequency, y*frequency);
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amplitude *= persistence;
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frequency *= lacunarity;
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}
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return sum;
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}
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// Tree cell Info
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const int TREE_MASTER_SEED_X = mt();
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const int TREE_MASTER_SEED_Z = mt();
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struct TreeCellInfo evaluateTreeCell(int wcx, int wcz){
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int anglex = TREE_MASTER_SEED_X*wcx+TREE_MASTER_SEED_Z*wcz;
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int anglez = TREE_MASTER_SEED_Z*wcz+TREE_MASTER_SEED_X*wcx;
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// Start at the center of the cell, with a bit of random offset
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int wcx_off = WOOD_CELL_CENTER + WOOD_MAX_OFFSET * sines[anglex % 360];
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int wcz_off = WOOD_CELL_CENTER + WOOD_MAX_OFFSET * cosines[anglez % 360];
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struct TreeCellInfo result{};
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// Cell to world coordinates
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result.trunk_x = wcx * WOOD_CELL_SIZE + wcx_off;
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result.trunk_z = wcz * WOOD_CELL_SIZE + wcz_off;
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result.trunk_x_offset = wcx_off;
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result.trunk_z_offset = wcz_off;
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result.leaves_y_pos = 1 + TREE_STANDARD_HEIGHT + GRASS_OFFSET + evaluateNoise(noiseGen1,
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result.trunk_x, result.trunk_z, NOISE_GRASS_MULT, 0.01, 0.35, 2.1, 5);
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return result;
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}
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void generateChunk(Chunk::Chunk *chunk)
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{
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generateNoise(chunk);
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}
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/* EXPERIMENTAL STUFF */
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void generateNoise3D(Chunk::Chunk *chunk) {
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Block block_prev{Block::AIR};
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Block block_prev{Block::AIR}, block;
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int block_prev_start{0};
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// A space filling curve is continuous, so there is no particular order
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@ -252,11 +265,3 @@ void generateNoise3D(Chunk::Chunk *chunk) {
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chunk->setBlocks(block_prev_start, CHUNK_VOLUME, block_prev);
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}
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void generatePyramid(Chunk::Chunk *chunk)
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{
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for (int i = 0; i < CHUNK_SIZE; i++)
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for (int j = 0; j < CHUNK_SIZE; j++)
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for (int k = 0; k < CHUNK_SIZE; k++)
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chunk->setBlock(i >= j && i < CHUNK_SIZE - j && k >= j && k < CHUNK_SIZE - j ? (j & 1) == 0 ? Block::GRASS : Block::STONE : Block::AIR, i, j, k);
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}
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