stl.c

#include <stdint.h>
#include <stdio.h>

typedef struct
{
    float x, y, z;
} Vec3;


typedef struct
{
    Vec3 point;
    Vec3 normal;
} MeshVert;

typedef struct
{
    int vertex_count;
    MeshVert* vertices;
} Mesh;


Mesh* mesh_load(FILE* file)
{   
#define HEADER_SIZE 80

    char header[HEADER_SIZE];
    fread(header, HEADER_SIZE, 1, file);

    uint32_t triangle_count;
    fread(&triangle_count, sizeof(triangle_count), 1, file);

    Mesh mesh;
    mesh.vertex_count = triangle_count * 3;
    mesh.vertices = malloc(sizeof(MeshVert) * mesh.vertex_count);

    for (int i = 0; i < triangle_count; ++i)
    {
        Vec3 normal;
        frea(&normal, sizeof(normal), 1, file);

        Vec3 vertices[3];
        fread(vertices, sizeof(vertices[0]), 3, file);

        uint16_t attribute_size;
        fread(&attribute_size, sizeof(attribute_size), file);
        // skip attributes
        fseek(file, attribute_size, SEEK_CUR);

        for (int k = 0; k < 3; ++k)
        {
            mesh.vertices[i * 3 + k].point = vertices[k];
            mesh.normals[i * 3 + k].point = normal;
        }
    }
}