skeleton.h

#pragma once

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

#include "linear_math/matrix.h"

//#define BONE_NAME_LENGTH 80
//#define SKELETON_MAX_BONE_COUNT 200
#define BONE_NAME_LENGTH 40
#define SKELETON_MAX_BONE_COUNT 70

namespace Anim
{
  struct bone
  {
    char Name[BONE_NAME_LENGTH];
    mat4 BindPose;
    mat4 InverseBindPose;

    int32_t ParentIndex;
  };

  struct skeleton // root is always the 0'th bone
  {
    int32_t BoneCount;
    bone    Bones[SKELETON_MAX_BONE_COUNT];
  };

  void PrintSkeleton(const skeleton* Skeleton);
  void AddBone(Anim::skeleton* Skeleton, Anim::bone Bone);
  int32_t GetBoneIndexFromName(const skeleton* Skeleton, const char* Name);

  inline void
  AddBone(Anim::skeleton* Skeleton, Anim::bone Bone)
  {
    assert(Skeleton->BoneCount < SKELETON_MAX_BONE_COUNT);
    assert(Skeleton->BoneCount >= 0);

    Skeleton->Bones[Skeleton->BoneCount++] = Bone;
  }

  inline int
  r_GetBoneDepth(const Anim::skeleton* Skeleton, int BoneIndex)
  {
    assert(BoneIndex >= 0 && BoneIndex < Skeleton->BoneCount);

    int ParentIndex = Skeleton->Bones[BoneIndex].ParentIndex;
    if(ParentIndex < 0)
    {
      return 0;
    }
    return 1 + r_GetBoneDepth(Skeleton, ParentIndex);
  }

  inline void
  PrintSkeleton(const skeleton* Skeleton)
  {
    for(int i = 0; i < Skeleton->BoneCount; i++)
    {
      const bone* Bone = &Skeleton->Bones[i];

      int BoneDepth = r_GetBoneDepth(Skeleton, i);
      for(int d = 0; d < BoneDepth; d++)
      {
        printf("  ");
      }
      printf("%d: %s\n", i, Bone->Name);
    }
  }

  inline int32_t
  GetBoneIndexFromName(const Anim::skeleton* Skeleton, const char* Name)
  {
    for(int i = 0; i < Skeleton->BoneCount; i++)
    {
      if(strcmp(Skeleton->Bones[i].Name, Name) == 0)
      {
        return i;
      }
    }
    return -1;
  }
}