refactor: move terrain generation and drawing to own file

1 files changed, 181 insertions, 0 deletions

diff --git a/world.c b/world.c
new file mode 100644
index 0000000..3b7c6ba
--- /dev/null
+++ b/world.c
@@ -0,0 +1,181 @@
+/*
+ * Tux-Town is a chill life-simulation game. 
+ * Copyright (C) 2025  orangerot <me@orangerot.dev>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <raylib.h>
+#include <stddef.h>
+
+#include "assets.h"
+#include "world.h"
+
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#define MAX(a,b) (((a)>(b))?(a):(b))
+#define CLAMP2(val, min, max) MIN(max, MAX(min, val))
+#define CLAMP(val, min, max) ((val) < (min) ? (min) : ((val) > (max) ? (max) : (val)))
+#define LROT(v,n) ((v << n) | (v >> (sizeof(v)*8 - n)))
+#define RROT(v,n) ((v >> n) | (v << (sizeof(v)*8 - n)))
+
+#define MAP_SIZE 64
+
+struct ModelDirection {
+  enum Asset asset;
+  unsigned char pattern;
+};
+
+struct ModelDirection rivers[] = {
+  /* 0b12345678
+   * 1 | 2 | 3
+   * 8 |   | 4
+   * 7 | 6 | 5
+   */
+  { .pattern = 0b11111111, .asset = ground_riverOpen },
+  // edge
+  { .pattern = 0b11011111, .asset = ground_riverCornerSmall },
+  { .pattern = 0b01011111, .asset = ground_riverSideOpen },
+  { .pattern = 0b11110001, .asset = ground_riverSide },
+  { .pattern = 0b01010101, .asset = ground_riverCross },
+  { .pattern = 0b01010001, .asset = ground_riverSplit },
+  // STRAIGHT
+  { .pattern = 0b01000100, .asset = ground_riverStraight },
+  // corner
+  { .pattern = 0b11000001, .asset = ground_riverCorner },
+  // L SHAPE
+  { .pattern = 0b01000001, .asset = ground_riverBend },
+  // closed
+  { .pattern = 0b01000000, .asset = ground_riverEndClosed },
+  { .pattern = 0b00000000, .asset = ground_riverTile },
+};
+
+void generate_river(struct World *world, int previous) {
+  Color *map_data = world->map_data;
+  int map_size = world->size;
+
+  int x = previous % map_size, y = previous / map_size;
+  if (x == 0 || x == map_size -1 || y == 0 || y == map_size -1) return;
+
+  int local_minimum_map_i = previous;
+  int local_minimum_val = 255;
+  int gradients[4][2] = {{0,-1},{-1,0},{0,1},{1,0}};
+  for (int gradient_i = 0; gradient_i < 4; gradient_i++) {
+    int dx = CLAMP(x + gradients[gradient_i][0], 0, map_size - 1);
+    int dy = CLAMP(y + gradients[gradient_i][1], 0, map_size - 1);
+    int i = dy * map_size + dx;
+    if (i == previous || map_data[i].r == 1) continue;
+    if (map_data[i].b < local_minimum_val) {
+      local_minimum_map_i = i; 
+      local_minimum_val = map_data[i].b;
+    }
+  }
+  if (local_minimum_val == 255) return;
+  map_data[local_minimum_map_i].r = 1;
+  generate_river(world, local_minimum_map_i);
+}
+
+void select_river_tile(struct World *world, int x, int y, size_t *river_i, size_t *direction) {
+  Color *map_data = world->map_data;
+  int map_size = world->size;
+
+  int surrounding[8][2] = {{-1,-1},{0,-1},{1,-1},{1,0},{1,1},{0,1},{-1,1},{-1,0}};
+  unsigned char river_tile = 0;
+  for (int surrounding_i = 0; surrounding_i < 8; surrounding_i++) {
+    int dx = CLAMP(x + surrounding[surrounding_i][0], 0, map_size - 1);
+    int dy = CLAMP(y + surrounding[surrounding_i][1], 0, map_size - 1);
+    if (map_data[dy * map_size + dx].r) 
+      river_tile |= 1 << (7 - surrounding_i);
+  } 
+  for (*river_i = 0; *river_i < 11; (*river_i)++) {
+    for (*direction = 0; *direction < 4; (*direction)++) {
+      if ((rivers[*river_i].pattern & RROT(river_tile, 2 * *direction)) == rivers[*river_i].pattern) {
+        return;
+      }
+    }
+  }
+}
+
+
+void gen_terrain(struct World *world) {
+  int map_size = world->size;
+  size_t global_minimum_map_i;
+  size_t global_minimum_val = 255;
+
+  world->map = GenImagePerlinNoise(map_size, map_size, 0, 0, 1.f);
+  world->map_texture = LoadTextureFromImage(world->map);
+  world->map_data = LoadImageColors(world->map);
+
+  for (size_t i = 0; i < map_size * map_size; i++) {
+    int x = i % map_size, y = i / map_size;
+    Color c = world->map_data[i];
+    if (c.r < global_minimum_val) {
+      global_minimum_map_i = i;
+      global_minimum_val = world->map_data[i].b;
+    }
+    world->map_data[i] = (Color) {
+      .r = 0,
+      .g = MAX(0, c.g - 64) / 32,
+      .b = c.b,
+      .a = 255
+    };
+  }
+
+  world->map_data[global_minimum_map_i].r = 1;
+  generate_river(world, global_minimum_map_i);
+  generate_river(world, global_minimum_map_i);
+}
+
+// void gen_room() {
+// 
+// }
+// 
+// void unload_world() {}
+
+void draw_world(struct World *world) {
+  int map_size = world->size;
+  Color *map_data = world->map_data;
+  Model wall = world->wall;
+  Model ground = world->floor;
+
+  for (int i = 0; i < map_size * map_size; i++) {
+    int x = i % map_size, y = i / map_size;
+    int gradients[4][2] = {{0,-1},{-1,0},{0,1},{1,0}};
+    for (int gradient_i = 0; gradient_i < 4; gradient_i++) {
+      int dx = CLAMP(x + gradients[gradient_i][0], 0, map_size - 1);
+      int dy = CLAMP(y + gradients[gradient_i][1], 0, map_size - 1);
+      for (int height = map_data[i].g; height < map_data[dy * map_size + dx].g; height++) {
+        DrawModelEx(wall,
+            (Vector3){
+            .x = map_size * (x / (float) map_size - 0.5f), 
+            .y = height,
+            .z = map_size * (y / (float) map_size - 0.5f)
+            },
+            (Vector3) {0, 1, 0}, gradient_i * 90.f, (Vector3) {1,1,1}, WHITE);
+      }
+    }
+    size_t river_i, direction;
+    if (map_data[i].r) {
+      select_river_tile(world, x, y, &river_i, &direction);
+    }
+    DrawModelEx(map_data[i].r ? assets[rivers[river_i].asset] : ground, 
+        (Vector3){
+        .x = map_size * (x / (float) map_size - 0.5f), 
+        .y = map_data[i].g, //- (map_gradient_magnitude_data[i].g < 2),
+        .z = map_size * (y / (float) map_size - 0.5f)
+        } , (Vector3) {0,1,0}, map_data[i].r ? direction * 90.f: 0, 
+        (Vector3) {1,1,1},
+        WHITE);
+  }
+}
+