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overhaul worldgen

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This commit is contained in:
p2r3
2025-08-16 16:15:33 +03:00
parent d36416cd2b
commit 7a3e2b5fa2
5 changed files with 126 additions and 51 deletions
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17
src/packets.c
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@@ -284,7 +284,7 @@ int sc_setCenterChunk (int client_fd, int x, int y) {
// S->C Chunk Data and Update Light
int sc_chunkDataAndUpdateLight (int client_fd, int _x, int _z) {
const int chunk_data_size = (4101 + sizeVarInt(256) + sizeof(network_block_palette)) * 20 + 6 * 4;
const int chunk_data_size = (4101 + sizeVarInt(256) + sizeof(network_block_palette)) * 20 + 6 * 12;
writeVarInt(client_fd, 17 + sizeVarInt(chunk_data_size) + chunk_data_size);
writeByte(client_fd, 0x27);
@@ -310,8 +310,8 @@ int sc_chunkDataAndUpdateLight (int client_fd, int _x, int _z) {
wdt_reset();
// send chunk sections
for (int i = 4; i < 24; i ++) {
y = i * 16 - 64;
for (int i = 0; i < 20; i ++) {
y = i * 16;
writeUint16(client_fd, 4096); // block count
writeByte(client_fd, 8); // bits per entry
writeVarInt(client_fd, 256); // block palette length
@@ -327,6 +327,17 @@ int sc_chunkDataAndUpdateLight (int client_fd, int _x, int _z) {
wdt_reset();
}
// send 8 chunk sections (up to Y=192) with no blocks
for (int i = 0; i < 8; i ++) {
writeUint16(client_fd, 4096); // block count
writeByte(client_fd, 0); // block bits
writeVarInt(client_fd, 0); // block palette (air)
writeByte(client_fd, 0); // biome bits
writeByte(client_fd, 0); // biome palette
}
// reset watchdog and yield
wdt_reset();
writeVarInt(client_fd, 0); // omit block entities
// light data

7
src/tools.c
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@@ -116,6 +116,13 @@ uint32_t fast_rand () {
return rng_seed;
}
uint64_t splitmix64 (uint64_t state) {
uint64_t z = state + 0x9e3779b97f4a7c15;
z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
return z ^ (z >> 31);
}
int client_states[MAX_PLAYERS * 2];
void setClientState (int client_fd, int new_state) {

1
src/tools.h
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@@ -26,6 +26,7 @@ double readDouble (int client_fd);
void readString (int client_fd);
uint32_t fast_rand ();
uint64_t splitmix64 (uint64_t state);
extern int client_states[MAX_PLAYERS * 2];

147
src/worldgen.c
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@@ -9,29 +9,6 @@
#include "registries.h"
#include "worldgen.h"
uint32_t getHash (const void *data, size_t len) {
const uint8_t *bytes = data;
uint32_t hash = 2166136261u;
for (size_t i = 0; i < len; i ++) {
hash ^= bytes[i];
hash *= 16777619u;
}
return hash;
}
int sapling (short x, short y, short z) {
uint8_t buf[10];
memcpy(buf, &x, 2);
memcpy(buf + 2, &y, 2);
memcpy(buf + 4, &z, 2);
memcpy(buf + 6, &world_seed, 4);
if (getHash(buf, sizeof(buf)) % 20 == 0) return B_oak_sapling;
return B_air;
}
uint32_t getChunkHash (short x, short z) {
uint8_t buf[8];
@@ -39,14 +16,26 @@ uint32_t getChunkHash (short x, short z) {
memcpy(buf + 2, &z, 2);
memcpy(buf + 4, &world_seed, 4);
return getHash(buf, sizeof(buf));
return splitmix64(*((uint64_t *)buf));
}
int getCornerHeight (uint32_t hash) {
int height = 60 + hash % 8 + (hash >> 8) % 5;
if (height < 64) height -= (hash >> 16) % 5;
// Use parts of the hash as random values for the height variation.
// We stack multiple different numbers to stabilize the distribution
// while allowing for occasional variances.
int height = terrain_base_height + (
(hash & 3) +
(hash >> 4 & 3) +
(hash >> 8 & 3) +
(hash >> 12 & 3)
);
// If height dips below sea level, push it down further
// This selectively makes bodies of water larger and deeper
if (height < 64) height -= (hash >> 24) & 7;
return height;
}
@@ -73,54 +62,58 @@ int getHeightAt (int rx, int rz, int _x, int _z, uint32_t chunk_hash) {
}
uint8_t getTerrainAt (int x, int y, int z) {
typedef struct {
short x;
short z;
uint32_t hash;
} ChunkAnchor;
uint8_t getTerrainAt (int x, int y, int z, ChunkAnchor anchor) {
if (y > 80) return B_air;
int _x = x / chunk_size;
int _z = z / chunk_size;
int rx = x % chunk_size;
int rz = z % chunk_size;
if (rx < 0) rx += chunk_size;
if (rz < 0) rz += chunk_size;
if (rx < 0) { rx += chunk_size; _x -= 1; }
if (rz < 0) { rz += chunk_size; _z -= 1; }
uint32_t chunk_hash = getChunkHash(_x, _z);
int height = getHeightAt(rx, rz, _x, _z, chunk_hash);
int height = getHeightAt(rx, rz, anchor.x, anchor.z, anchor.hash);
if (y >= 64 && y >= height) {
uint8_t tree_position = chunk_hash % (chunk_size * chunk_size);
uint8_t tree_position = anchor.hash % (chunk_size * chunk_size);
short tree_x = tree_position % chunk_size;
if (tree_x < 3 || tree_x > chunk_size - 3) goto skip_tree;
tree_x += _x * chunk_size;
short tree_z = tree_position / chunk_size;
if (tree_z < 3 || tree_z > chunk_size - 3) goto skip_tree;
tree_z += _z * chunk_size;
uint8_t tree_short = (anchor.hash >> (tree_x + tree_z)) & 1;
tree_x += anchor.x * chunk_size;
tree_z += anchor.z * chunk_size;
uint8_t tree_y = getHeightAt(
tree_x < 0 ? tree_x % chunk_size + chunk_size : tree_x % chunk_size,
tree_z < 0 ? tree_z % chunk_size + chunk_size : tree_z % chunk_size,
_x, _z, chunk_hash
anchor.x, anchor.z, anchor.hash
) + 1;
if (tree_y < 64) goto skip_tree;
if (x == tree_x && z == tree_z) {
if (y == tree_y - 1) return B_dirt;
if (y >= tree_y && y < tree_y + 6) return B_oak_log;
if (y >= tree_y && y < tree_y - tree_short + 6) return B_oak_log;
}
uint8_t dx = x > tree_x ? x - tree_x : tree_x - x;
uint8_t dz = z > tree_z ? z - tree_z : tree_z - z;
if (dx < 3 && dz < 3 && y > tree_y + 2 && y < tree_y + 5) {
if (y == tree_y + 4 && dx == 2 && dz == 2 && (chunk_hash >> (x + z + y)) & 1) return B_air;
if (dx < 3 && dz < 3 && y > tree_y - tree_short + 2 && y < tree_y - tree_short + 5) {
if (y == tree_y - tree_short + 4 && dx == 2 && dz == 2) return B_air;
return B_oak_leaves;
}
if (dx < 2 && dz < 2 && y >= tree_y + 5 && y <= tree_y + 6) {
if (y == tree_y + 6 && dx == 1 && dz == 1 && (chunk_hash >> (x + z + y)) & 1) return B_air;
if (dx < 2 && dz < 2 && y >= tree_y - tree_short + 5 && y <= tree_y - tree_short + 6) {
if (y == tree_y - tree_short + 6 && dx == 1 && dz == 1) return B_air;
return B_oak_leaves;
}
@@ -130,11 +123,44 @@ uint8_t getTerrainAt (int x, int y, int z) {
}
skip_tree:
if (y >= 63 && y == height) return B_grass_block;
if (y < height - 3) return B_stone;
// For surface-level terrain, generate grass blocks
if (y == height && height >= 63) return B_grass_block;
// Starting at 4 blocks below terrain level, generate minerals and caves
if (y <= height - 4) {
// Caves use the same shape as surface terrain, just mirrored
int8_t gap = height - terrain_base_height;
if (y < cave_base_depth + gap && y > cave_base_depth - gap) return B_air;
// The chunk-relative X and Z coordinates are used in a bit shift on the hash
// The sum of these is then used to get the Y coordinate of the ore in this column
// This way, each column is guaranteed to have exactly one ore candidate
uint8_t ore_x_component = (anchor.hash >> rx) & 31;
uint8_t ore_z_component = (anchor.hash >> (rz + 16)) & 31;
uint8_t ore_y = ore_x_component + ore_z_component;
if (y == ore_y) {
// Since the ore Y coordinate is effectely a random number in range [0;64],
// we use it in another bit shift to get a pseudo-random number for the column
uint8_t ore_probability = (anchor.hash >> ore_y) & 127;
// Ore placement is determined by Y level and "probability"
if (y < 15 && ore_probability < 15) return B_diamond_ore;
if (y < 30) {
if (ore_probability < 5) return B_gold_ore;
if (ore_probability < 20) return B_redstone_ore;
}
if (y < 54 && ore_probability < 50) return B_iron_ore;
if (ore_probability < 60) return B_coal_ore;
}
// For everything else, fall back to stone
return B_stone;
}
// Under water and in the space between stone and grass, generate dirt
if (y <= height) return B_dirt;
// If all else failed, but we're below sea level, generate water
if (y < 64) return B_water;
// For everything else, fall back to air
return B_air;
}
@@ -144,14 +170,38 @@ uint8_t getBlockAt (int x, int y, int z) {
uint8_t block_change = getBlockChange(x, y, z);
if (block_change != 0xFF) return block_change;
return getTerrainAt(x, y, z);
ChunkAnchor anchor = {
x / chunk_size,
z / chunk_size
};
if (x % chunk_size < 0) anchor.x --;
if (z % chunk_size < 0) anchor.z --;
anchor.hash = getChunkHash(anchor.x, anchor.z);
return getTerrainAt(x, y, z, anchor);
}
uint8_t chunk_section[4096];
ChunkAnchor chunk_anchors[256 / (chunk_size * chunk_size)];
void buildChunkSection (int cx, int cy, int cz) {
// Precompute the hashes and anchors for each minichunk
int anchor_index = 0;
for (int i = cz; i < cz + 16; i += chunk_size) {
for (int j = cx; j < cx + 16; j += chunk_size) {
ChunkAnchor *anchor = chunk_anchors + anchor_index;
anchor->x = j / chunk_size;
anchor->z = i / chunk_size;
anchor->hash = getChunkHash(anchor->x, anchor->z);
anchor_index ++;
}
}
// Generate 4096 blocks in one buffer to reduce overhead
for (int j = 0; j < 4096; j += 8) {
// These values don't change in the lower array,
@@ -161,10 +211,11 @@ void buildChunkSection (int cx, int cy, int cz) {
// The client expects "big-endian longs", which in our
// case means reversing the order in which we store/send
// each 8 block sequence.
anchor_index = (j % 16) / chunk_size + (j / 16 % 16) / chunk_size * 2;
for (int offset = 7; offset >= 0; offset--) {
int k = j + offset;
int x = k % 16 + cx;
chunk_section[j + 7 - offset] = getTerrainAt(x, y, z);
chunk_section[j + 7 - offset] = getTerrainAt(x, y, z, chunk_anchors[anchor_index]);
}
}

5
src/worldgen.h
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@@ -3,7 +3,12 @@
#include <stdint.h>
// For best performance, chunk_size should be a power of 2
#define chunk_size 8
// Terrain low point - should start a bit below sea level for rivers/lakes
#define terrain_base_height 60
// Center point of cave generation
#define cave_base_depth 24
uint32_t getChunkHash (short x, short z);
int getHeightAt (int rx, int rz, int _x, int _z, uint32_t chunk_hash);