refactor: reorganize pxl8 into client/src/ module structure

- core/: main entry, types, logging, I/O, RNG
- asset/: ase loader, cart, save, embed
- gfx/: graphics, animation, atlas, fonts, tilemap, transitions
- sfx/: audio
- script/: lua/fennel runtime, REPL
- hal/: platform abstraction (SDL3)
- world/: BSP, world, procedural gen
- math/: math utilities
- game/: GUI, replay
- lua/: Lua API modules

client/src/world/pxl8_bsp.h

@@ -0,0 +1,164 @@
+#pragma once
+
+#include "pxl8_gfx.h"
+#include "pxl8_math.h"
+#include "pxl8_mesh.h"
+#include "pxl8_types.h"
+
+typedef struct pxl8_bsp_edge {
+    u16 vertex[2];
+} pxl8_bsp_edge;
+
+typedef struct pxl8_bsp_face {
+    u32 first_edge;
+    u32 lightmap_offset;
+    u16 num_edges;
+    u16 plane_id;
+    u16 side;
+
+    u8 styles[4];
+    u16 texinfo_id;
+
+    pxl8_vec3 aabb_min;
+    pxl8_vec3 aabb_max;
+} pxl8_bsp_face;
+
+typedef struct pxl8_bsp_leaf {
+    u8 ambient_level[4];
+    i32 contents;
+
+    u16 first_marksurface;
+    i16 maxs[3];
+    i16 mins[3];
+    u16 num_marksurfaces;
+
+    i32 visofs;
+} pxl8_bsp_leaf;
+
+typedef struct pxl8_bsp_model {
+    i32 first_face;
+    i32 headnode[4];
+    f32 maxs[3];
+    f32 mins[3];
+    i32 num_faces;
+
+    pxl8_vec3 origin;
+    i32 visleafs;
+} pxl8_bsp_model;
+
+typedef struct pxl8_bsp_node {
+    i32 children[2];
+
+    u16 first_face;
+    i16 maxs[3];
+    i16 mins[3];
+    u16 num_faces;
+
+    u32 plane_id;
+} pxl8_bsp_node;
+
+typedef struct pxl8_bsp_plane {
+    f32 dist;
+    pxl8_vec3 normal;
+    i32 type;
+} pxl8_bsp_plane;
+
+typedef struct pxl8_bsp_texinfo {
+    u32 miptex;
+    char name[16];
+
+    f32 u_offset;
+    pxl8_vec3 u_axis;
+
+    f32 v_offset;
+    pxl8_vec3 v_axis;
+} pxl8_bsp_texinfo;
+
+typedef struct pxl8_bsp_vertex {
+    pxl8_vec3 position;
+} pxl8_bsp_vertex;
+
+typedef struct pxl8_bsp_lightmap {
+    u8 color[3];
+    u8 height;
+    u32 offset;
+    u8 width;
+} pxl8_bsp_lightmap;
+
+typedef struct pxl8_bsp_lightmap_sample {
+    u8 b;
+    u8 g;
+    u8 r;
+} pxl8_bsp_lightmap_sample;
+
+typedef struct pxl8_bsp_material_batch {
+    u16* face_indices;
+    u32 face_count;
+    u8 material_id;
+    pxl8_mesh* mesh;
+} pxl8_bsp_material_batch;
+
+typedef struct pxl8_bsp_pvs {
+    u8* data;
+    u32 size;
+} pxl8_bsp_pvs;
+
+typedef struct pxl8_bsp {
+    pxl8_bsp_edge* edges;
+    pxl8_bsp_face* faces;
+    pxl8_bsp_leaf* leafs;
+    u8* lightdata;
+    pxl8_bsp_lightmap* lightmaps;
+    u16* marksurfaces;
+    pxl8_bsp_material_batch* material_batches;
+    pxl8_bsp_model* models;
+    pxl8_bsp_node* nodes;
+    pxl8_bsp_plane* planes;
+    i32* surfedges;
+    pxl8_bsp_texinfo* texinfo;
+    u32* vertex_lights;
+    pxl8_bsp_vertex* vertices;
+    u8* visdata;
+
+    u32 lightdata_size;
+    u32 num_edges;
+    u32 num_faces;
+    u32 num_leafs;
+    u32 num_lightmaps;
+    u32 num_marksurfaces;
+    u32 num_material_batches;
+    u32 num_models;
+    u32 num_nodes;
+    u32 num_planes;
+    u32 num_surfedges;
+    u32 num_texinfo;
+    u32 num_vertex_lights;
+    u32 num_vertices;
+    u32 visdata_size;
+} pxl8_bsp;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+pxl8_result pxl8_bsp_load(const char* path, pxl8_bsp* bsp);
+void pxl8_bsp_destroy(pxl8_bsp* bsp);
+
+i32 pxl8_bsp_find_leaf(const pxl8_bsp* bsp, pxl8_vec3 pos);
+bool pxl8_bsp_is_leaf_visible(const pxl8_bsp* bsp, i32 leaf_from, i32 leaf_to);
+
+pxl8_bsp_pvs pxl8_bsp_decompress_pvs(const pxl8_bsp* bsp, i32 leaf);
+void pxl8_bsp_pvs_destroy(pxl8_bsp_pvs* pvs);
+bool pxl8_bsp_pvs_is_visible(const pxl8_bsp_pvs* pvs, i32 leaf);
+
+pxl8_bsp_lightmap pxl8_bsp_lightmap_uniform(u8 r, u8 g, u8 b);
+pxl8_bsp_lightmap pxl8_bsp_lightmap_mapped(u8 width, u8 height, u32 offset);
+pxl8_bsp_lightmap_sample pxl8_bsp_sample_lightmap(const pxl8_bsp* bsp, u32 face_idx, f32 u, f32 v);
+
+void pxl8_bsp_render_face(pxl8_gfx* gfx, const pxl8_bsp* bsp, u32 face_id, u32 texture_id);
+void pxl8_bsp_render_textured(pxl8_gfx* gfx, const pxl8_bsp* bsp, pxl8_vec3 camera_pos);
+void pxl8_bsp_render_wireframe(pxl8_gfx* gfx, const pxl8_bsp* bsp, pxl8_vec3 camera_pos, u32 color);
+
+#ifdef __cplusplus
+}
+#endif