pxl8/demo3d/client/bsp/demo3d_bsp.h

#pragma once

#include "pxl8_math.h"
#include "pxl8_types.h"

typedef struct demo3d_bsp_edge {
    u16 vertex[2];
} demo3d_bsp_edge;

typedef struct demo3d_bsp_face {
    u32 first_edge;
    u32 lightmap_offset;
    u16 num_edges;
    u16 plane_id;
    u16 side;

    u8 styles[4];
    u16 material_id;

    pxl8_vec3 aabb_min;
    pxl8_vec3 aabb_max;
} demo3d_bsp_face;

typedef struct demo3d_bsp_leaf {
    u8 ambient_level[4];
    i32 contents;

    u16 first_marksurface;
    i16 maxs[3];
    i16 mins[3];
    u16 num_marksurfaces;

    i32 visofs;
} demo3d_bsp_leaf;

typedef struct demo3d_bsp_model {
    i32 first_face;
    i32 headnode[4];
    f32 maxs[3];
    f32 mins[3];
    i32 num_faces;

    pxl8_vec3 origin;
    i32 visleafs;
} demo3d_bsp_model;

typedef struct demo3d_bsp_node {
    i32 children[2];

    u16 first_face;
    i16 maxs[3];
    i16 mins[3];
    u16 num_faces;

    u32 plane_id;
} demo3d_bsp_node;

typedef struct demo3d_bsp_plane {
    f32 dist;
    pxl8_vec3 normal;
    i32 type;
} demo3d_bsp_plane;


typedef struct demo3d_bsp_vertex {
    pxl8_vec3 position;
} demo3d_bsp_vertex;

typedef struct demo3d_bsp_lightmap {
    u8 color[3];
    u8 height;
    u32 offset;
    u8 width;
} demo3d_bsp_lightmap;

typedef struct demo3d_bsp_lightmap_sample {
    u8 b;
    u8 g;
    u8 r;
} demo3d_bsp_lightmap_sample;

typedef struct demo3d_bsp_pvs {
    u8* data;
    u32 size;
} demo3d_bsp_pvs;

typedef struct demo3d_bsp_portal {
    f32 x0, z0;
    f32 x1, z1;
    u32 target_leaf;
} demo3d_bsp_portal;

typedef struct demo3d_bsp_cell_portals {
    demo3d_bsp_portal portals[4];
    u8 num_portals;
} demo3d_bsp_cell_portals;

typedef struct demo3d_bsp {
    demo3d_bsp_cell_portals* cell_portals;
    demo3d_bsp_edge* edges;
    demo3d_bsp_face* faces;
    demo3d_bsp_leaf* leafs;
    u8* lightdata;
    demo3d_bsp_lightmap* lightmaps;
    u16* marksurfaces;
    demo3d_bsp_model* models;
    demo3d_bsp_node* nodes;
    demo3d_bsp_plane* planes;
    i32* surfedges;
    u32* vertex_lights;
    demo3d_bsp_vertex* vertices;
    u8* visdata;
    f32* heightfield;

    u32 lightdata_size;
    u32 num_cell_portals;
    u32 num_edges;
    u32 num_faces;
    u32 num_leafs;
    u32 num_lightmaps;
    u32 num_marksurfaces;
    u32 num_models;
    u32 num_nodes;
    u32 num_planes;
    u32 num_surfedges;
    u32 num_vertex_lights;
    u32 num_vertices;
    u32 num_heightfield;
    f32 heightfield_ox;
    f32 heightfield_oz;
    f32 heightfield_cell_size;
    u16 heightfield_w;
    u16 heightfield_h;
    u32 visdata_size;
    f32 bounds_min_x;
    f32 bounds_min_z;
    f32 bounds_max_x;
    f32 bounds_max_z;
} demo3d_bsp;

static inline bool demo3d_bsp_get_edge_vertex(const demo3d_bsp* bsp, i32 surfedge_idx, u32* out_vert_idx) {
    if (surfedge_idx >= (i32)bsp->num_surfedges) return false;

    i32 edge_idx = bsp->surfedges[surfedge_idx];
    u32 vertex_index;

    if (edge_idx >= 0) {
        if ((u32)edge_idx >= bsp->num_edges) return false;
        vertex_index = 0;
    } else {
        edge_idx = -edge_idx;
        if ((u32)edge_idx >= bsp->num_edges) return false;
        vertex_index = 1;
    }

    *out_vert_idx = bsp->edges[edge_idx].vertex[vertex_index];
    return *out_vert_idx < bsp->num_vertices;
}

static inline u8 demo3d_bsp_vertex_light(const demo3d_bsp* bsp, u32 vert_idx, u8 ambient) {
    if (!bsp->vertex_lights || vert_idx >= bsp->num_vertex_lights) return 255;
    u32 packed = bsp->vertex_lights[vert_idx];
    u8 direct = (packed >> 24) & 0xFF;
    u8 ao = (packed >> 16) & 0xFF;
    f32 combined = (f32)direct + ((f32)ambient / 255.0f) * (f32)ao;
    return (u8)(combined > 255.0f ? 255.0f : combined);
}

static inline i32 demo3d_bsp_find_leaf(const demo3d_bsp* bsp, pxl8_vec3 pos) {
    if (!bsp || bsp->num_nodes == 0) return -1;
    i32 node_id = 0;
    while (node_id >= 0) {
        const demo3d_bsp_node* node = &bsp->nodes[node_id];
        const demo3d_bsp_plane* plane = &bsp->planes[node->plane_id];
        f32 dist = pxl8_vec3_dot(pos, plane->normal) - plane->dist;
        node_id = node->children[dist < 0 ? 1 : 0];
    }
    return -(node_id + 1);
}

#ifdef __cplusplus
extern "C" {
#endif

demo3d_bsp_pvs demo3d_bsp_decompress_pvs(const demo3d_bsp* bsp, i32 leaf);
void demo3d_bsp_destroy(demo3d_bsp* bsp);
u32 demo3d_bsp_face_count(const demo3d_bsp* bsp);
pxl8_vec3 demo3d_bsp_face_normal(const demo3d_bsp* bsp, u32 face_id);
void demo3d_bsp_face_set_material(demo3d_bsp* bsp, u32 face_id, u16 material_id);
bool demo3d_bsp_is_leaf_visible(const demo3d_bsp* bsp, i32 leaf_from, i32 leaf_to);
demo3d_bsp_lightmap demo3d_bsp_lightmap_mapped(u8 width, u8 height, u32 offset);
demo3d_bsp_lightmap demo3d_bsp_lightmap_uniform(u8 r, u8 g, u8 b);
pxl8_result demo3d_bsp_load(const char* path, demo3d_bsp* bsp);
void demo3d_bsp_pvs_destroy(demo3d_bsp_pvs* pvs);
bool demo3d_bsp_pvs_is_visible(const demo3d_bsp_pvs* pvs, i32 leaf);
u8 demo3d_bsp_light_at(const demo3d_bsp* bsp, f32 x, f32 y, f32 z, u8 ambient);
demo3d_bsp_lightmap_sample demo3d_bsp_sample_lightmap(const demo3d_bsp* bsp, u32 face_idx, f32 u, f32 v);

#ifdef __cplusplus
}
#endif