#ifndef EZ3D_TRIMESH_H
#define EZ3D_TRIMESH_H

#include <stddef.h>
#include <stdint.h>

#include "triangle.h"

/* An indexed triangle mesh in memory. Vertices are deduplicated by exact
 * float32 equality -- legitimate because the mesher generates every copy
 * of a shared corner from the same vertex grid, so coordinates that should
 * match match bit-for-bit. Vertex ids are stable for the mesh's lifetime
 * (append-only array), which the decimator relies on. */
typedef struct {
    vertex_t *v;       /* nv structs, which is nv * 3 floats */
    triangle_t *tri;   /* ntri structs, which is ntri * 3 vertex ids */
    size_t nv, ntri;
    size_t capv, captri;

    /* dedup hash: bucket chains over stable vertex ids */
    uint32_t *buckets;
    uint32_t *next;
    size_t nbuckets;
} trimesh_t;

void tm_init(trimesh_t *m);
void tm_free(trimesh_t *m);

/*
 * Return the id of the vertex at (v->x, v->y, v->z), appending it if new.
 */
uint32_t tm_vertex(trimesh_t *m, const vertex_t *v);

/* Append a vertex unconditionally, no dedup, and return its id. Used by
 * the decimator's compaction: survivors must keep distinct ids even when
 * two of them happened to land on identical coordinates, otherwise two
 * triangle fans get glued into a non-manifold point. */
uint32_t tm_append(trimesh_t *m, const vertex_t *v);

/* Append a triangle by vertex ids (no dedup -- ids must be valid). */
void tm_tri(trimesh_t *m, const triangle_t *t);

#endif /* EZ3D_TRIMESH_H */