1 files changed, 138 insertions, 0 deletions
diff --git a/src/chunk.c b/src/chunk.c
new file mode 100644
index 0000000..50fe5c3
--- /dev/null
+++ b/src/chunk.c
@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "voxel.h"
+#include "list.h"
+#include "cube.h"
+#include "mesh.h"
+
+Chunk *chunk_init(int x, int y, int z)
+{
+	Chunk *chunk = malloc(sizeof(Chunk));
+	chunk->x = x;
+	chunk->y = y;
+	chunk->z = z;
+	memset(chunk->blocks, AIR, sizeof(chunk->blocks));
+	return chunk;
+}
+
+void chunk_free(Chunk *chunk)
+{
+	free(chunk);
+}
+
+void chunk_generate(Chunk *chunk)
+{
+	int size = sizeof(chunk->blocks);
+	for (int i = 0; i < size; i++) {
+		int x = i % CHUNK_SIZE;
+		int z = (i / CHUNK_SIZE) % CHUNK_SIZE;
+		int y = i / (CHUNK_SIZE * CHUNK_SIZE);
+
+		char block = AIR;
+		int temp = x + z - y;
+		if (temp > 16)
+			block = DIRT;
+
+		chunk->blocks[i] = block;
+	}
+}
+
+typedef struct {
+	Chunk *chunk;
+	List pos;
+	List data;
+	int vertex_count;
+} MeshState;
+
+static void add_vertex(MeshState *state, const vec3 pos, const vec3 xyz, unsigned int data)
+{
+	list_pushf(&state->pos, pos[0] + xyz[0]);
+	list_pushf(&state->pos, pos[1] + xyz[1]);
+	list_pushf(&state->pos, pos[2] + xyz[2]);
+	list_pushu(&state->data, data);
+	state->vertex_count++;
+}
+
+static void add_quad(MeshState *state, const vec3 xyz, Face face, Block block)
+{
+	unsigned int data = (face << 2) | block;
+	const vec3 *verts = CUBE[face];
+
+	add_vertex(state, verts[0], xyz, data);
+	add_vertex(state, verts[1], xyz, data);
+	add_vertex(state, verts[2], xyz, data);
+	add_vertex(state, verts[3], xyz, data);
+	add_vertex(state, verts[4], xyz, data);
+	add_vertex(state, verts[5], xyz, data);
+}
+
+Mesh chunk_mesh(Chunk *chunk)
+{
+	MeshState state;
+	state.chunk = chunk;
+	state.vertex_count = 0;
+	list_initf(&state.pos);
+	list_initu(&state.data);
+
+	int size = sizeof(chunk->blocks);
+	for (int i = 0; i < size; i++) {
+		int x = i % CHUNK_SIZE;
+		int z = (i / CHUNK_SIZE) % CHUNK_SIZE;
+		int y = i / (CHUNK_SIZE * CHUNK_SIZE);
+		vec3 xyz = { x, y, z };
+
+		Block block = chunk->blocks[i];
+		if (block == AIR)
+			continue;
+
+		Block px = chunk_at(chunk, x + 1, y, z);
+		Block nx = chunk_at(chunk, x - 1, y, z);
+		Block py = chunk_at(chunk, x, y + 1, z);
+		Block ny = chunk_at(chunk, x, y - 1, z);
+		Block pz = chunk_at(chunk, x, y, z + 1);
+		Block nz = chunk_at(chunk, x, y, z - 1);
+
+		if (px == AIR)
+			add_quad(&state, xyz, POS_X, block);
+		if (nx == AIR)
+			add_quad(&state, xyz, NEG_X, block);
+		if (py == AIR)
+			add_quad(&state, xyz, POS_Y, block);
+		if (ny == AIR)
+			add_quad(&state, xyz, NEG_Y, block);
+		if (pz == AIR)
+			add_quad(&state, xyz, POS_Z, block);
+		if (nz == AIR)
+			add_quad(&state, xyz, NEG_Z, block);
+	}
+
+	Mesh mesh;
+	mesh_init(&mesh, state.vertex_count);
+	mesh_storef(&mesh, state.pos.fdata, state.pos.len, 3);
+	mesh_storeu(&mesh, state.data.udata, state.data.len, 1);
+	mesh_finish();
+
+	list_free(&state.pos);
+	list_free(&state.data);
+
+	return mesh;
+}
+
+Block chunk_at(Chunk *chunk, int x, int y, int z)
+{
+	if (x < 0 || x >= CHUNK_SIZE)
+		return AIR;
+	if (y < 0 || y >= CHUNK_SIZE)
+		return AIR;
+	if (z < 0 || z >= CHUNK_SIZE)
+		return AIR;
+
+	int i = 0;
+	i += x;
+	i += z * CHUNK_SIZE;
+	i += y * CHUNK_SIZE * CHUNK_SIZE;
+
+	return chunk->blocks[i];
+}